sql_select.cc 257 KB
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/* Copyright (C) 2000-2003 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


/* mysql_select and join optimization */

#ifdef __GNUC__
#pragma implementation				// gcc: Class implementation
#endif

#include "mysql_priv.h"
#include "sql_select.h"
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#include "opt_ft.h"
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#include <m_ctype.h>
#include <hash.h>
#include <ft_global.h>

const char *join_type_str[]={ "UNKNOWN","system","const","eq_ref","ref",
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			      "MAYBE_REF","ALL","range","index","fulltext",
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			      "ref_or_null","unique_subquery","index_subquery"
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};
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const key_map key_map_empty(0);
const key_map key_map_full(~0);

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static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array);
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static bool make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
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				 DYNAMIC_ARRAY *keyuse);
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static bool update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,
				JOIN_TAB *join_tab,
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                                uint tables, COND *conds,
				table_map table_map, SELECT_LEX *select_lex);
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static int sort_keyuse(KEYUSE *a,KEYUSE *b);
static void set_position(JOIN *join,uint index,JOIN_TAB *table,KEYUSE *key);
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static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
			       table_map used_tables);
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static void find_best_combination(JOIN *join,table_map rest_tables);
static void find_best(JOIN *join,table_map rest_tables,uint index,
		      double record_count,double read_time);
static uint cache_record_length(JOIN *join,uint index);
static double prev_record_reads(JOIN *join,table_map found_ref);
static bool get_best_combination(JOIN *join);
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static store_key *get_store_key(THD *thd,
				KEYUSE *keyuse, table_map used_tables,
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				KEY_PART_INFO *key_part, char *key_buff,
				uint maybe_null);
static bool make_simple_join(JOIN *join,TABLE *tmp_table);
static bool make_join_select(JOIN *join,SQL_SELECT *select,COND *item);
static void make_join_readinfo(JOIN *join,uint options);
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static bool only_eq_ref_tables(JOIN *join, ORDER *order, table_map tables);
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static void update_depend_map(JOIN *join);
static void update_depend_map(JOIN *join, ORDER *order);
static ORDER *remove_const(JOIN *join,ORDER *first_order,COND *cond,
			   bool *simple_order);
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static int return_zero_rows(JOIN *join, select_result *res,TABLE_LIST *tables,
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			    List<Item> &fields, bool send_row,
			    uint select_options, const char *info,
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			    Item *having, Procedure *proc,
			    SELECT_LEX_UNIT *unit);
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static COND *optimize_cond(COND *conds,Item::cond_result *cond_value);
static COND *remove_eq_conds(COND *cond,Item::cond_result *cond_value);
static bool const_expression_in_where(COND *conds,Item *item, Item **comp_item);
static bool open_tmp_table(TABLE *table);
static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
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				    ulong options);
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static int do_select(JOIN *join,List<Item> *fields,TABLE *tmp_table,
		     Procedure *proc);
static int sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records);
static int sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records);
static int flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skipp_last);
static int end_send(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_send_group(JOIN *join, JOIN_TAB *join_tab,bool end_of_records);
static int end_write(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_update(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
static int end_unique_update(JOIN *join,JOIN_TAB *join_tab,
			     bool end_of_records);
static int end_write_group(JOIN *join, JOIN_TAB *join_tab,
			   bool end_of_records);
static int test_if_group_changed(List<Item_buff> &list);
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static int join_read_const_table(JOIN_TAB *tab, POSITION *pos);
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static int join_read_system(JOIN_TAB *tab);
static int join_read_const(JOIN_TAB *tab);
static int join_read_key(JOIN_TAB *tab);
static int join_read_always_key(JOIN_TAB *tab);
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static int join_read_last_key(JOIN_TAB *tab);
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static int join_no_more_records(READ_RECORD *info);
static int join_read_next(READ_RECORD *info);
static int join_init_quick_read_record(JOIN_TAB *tab);
static int test_if_quick_select(JOIN_TAB *tab);
static int join_init_read_record(JOIN_TAB *tab);
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static int join_read_first(JOIN_TAB *tab);
static int join_read_next(READ_RECORD *info);
static int join_read_next_same(READ_RECORD *info);
static int join_read_last(JOIN_TAB *tab);
static int join_read_prev_same(READ_RECORD *info);
static int join_read_prev(READ_RECORD *info);
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static int join_ft_read_first(JOIN_TAB *tab);
static int join_ft_read_next(READ_RECORD *info);
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static int join_read_always_key_or_null(JOIN_TAB *tab);
static int join_read_next_same_or_null(READ_RECORD *info);
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static COND *make_cond_for_table(COND *cond,table_map table,
				 table_map used_table);
static Item* part_of_refkey(TABLE *form,Field *field);
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static uint find_shortest_key(TABLE *table, const key_map *usable_keys);
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static bool test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,
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				    ha_rows select_limit, bool no_changes);
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static int create_sort_index(THD *thd, JOIN *join, ORDER *order,
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			     ha_rows filesort_limit, ha_rows select_limit);
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static int remove_duplicates(JOIN *join,TABLE *entry,List<Item> &fields,
			     Item *having);
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static int remove_dup_with_compare(THD *thd, TABLE *entry, Field **field,
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				   ulong offset,Item *having);
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static int remove_dup_with_hash_index(THD *thd, TABLE *table,
				      uint field_count, Field **first_field,
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				      ulong key_length,Item *having);
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static int join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count);
static ulong used_blob_length(CACHE_FIELD **ptr);
static bool store_record_in_cache(JOIN_CACHE *cache);
static void reset_cache(JOIN_CACHE *cache);
static void read_cached_record(JOIN_TAB *tab);
static bool cmp_buffer_with_ref(JOIN_TAB *tab);
static bool setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
			     List<Item> &all_fields,ORDER *new_order);
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static ORDER *create_distinct_group(THD *thd, ORDER *order,
				    List<Item> &fields,
				    bool *all_order_by_fields_used);
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static bool test_if_subpart(ORDER *a,ORDER *b);
static TABLE *get_sort_by_table(ORDER *a,ORDER *b,TABLE_LIST *tables);
static void calc_group_buffer(JOIN *join,ORDER *group);
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static bool make_group_fields(JOIN *main_join, JOIN *curr_join);
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static bool alloc_group_fields(JOIN *join,ORDER *group);
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// Create list for using with tempory table
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static bool change_to_use_tmp_fields(THD *thd, Item **ref_pointer_array,
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				     List<Item> &new_list1,
				     List<Item> &new_list2,
				     uint elements, List<Item> &items);
// Create list for using with tempory table
static bool change_refs_to_tmp_fields(THD *thd, Item **ref_pointer_array,
				      List<Item> &new_list1,
				      List<Item> &new_list2,
				      uint elements, List<Item> &items);
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static void init_tmptable_sum_functions(Item_sum **func);
static void update_tmptable_sum_func(Item_sum **func,TABLE *tmp_table);
static void copy_sum_funcs(Item_sum **func_ptr);
static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab);
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static bool init_sum_functions(Item_sum **func, Item_sum **end);
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static bool update_sum_func(Item_sum **func);
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static void select_describe(JOIN *join, bool need_tmp_table,bool need_order,
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			    bool distinct, const char *message=NullS);
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static Item *remove_additional_cond(Item* conds);
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/*
  This handles SELECT with and without UNION
*/

int handle_select(THD *thd, LEX *lex, select_result *result)
{
  int res;
  register SELECT_LEX *select_lex = &lex->select_lex;
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  DBUG_ENTER("handle_select");

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  if (select_lex->next_select())
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    res=mysql_union(thd, lex, result, &lex->unit);
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  else
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    res= mysql_select(thd, &select_lex->ref_pointer_array,
		      (TABLE_LIST*) select_lex->table_list.first,
		      select_lex->with_wild, select_lex->item_list,
		      select_lex->where,
		      select_lex->order_list.elements +
		      select_lex->group_list.elements,
		      (ORDER*) select_lex->order_list.first,
		      (ORDER*) select_lex->group_list.first,
		      select_lex->having,
		      (ORDER*) lex->proc_list.first,
		      select_lex->options | thd->options,
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		      result, &(lex->unit), &(lex->select_lex));
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  /* Don't set res if it's -1 as we may want this later */
  DBUG_PRINT("info",("res: %d  report_error: %d", res,
		     thd->net.report_error));
  if (thd->net.report_error)
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    res= 1;
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  if (res)
  {
    if (result)
    {
      result->send_error(0, NullS);
      result->abort();
    }
    else
      send_error(thd, 0, NullS);
    res= 1;					// Error sent to client
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  }
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  delete result;
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  DBUG_RETURN(res);
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}

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void relink_tables(SELECT_LEX *select_lex)
{
  for (TABLE_LIST *cursor= (TABLE_LIST *) select_lex->table_list.first;
       cursor;
       cursor=cursor->next)
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    if (cursor->table_list)
      cursor->table= cursor->table_list->table;
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}


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void fix_tables_pointers(SELECT_LEX *select_lex)
{
  if (select_lex->next_select_in_list())
  {
    /* Fix tables 'to-be-unioned-from' list to point at opened tables */
    for (SELECT_LEX *sl= select_lex;
	 sl;
	 sl= sl->next_select_in_list())
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      relink_tables(sl);
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  }
}
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void fix_tables_pointers(SELECT_LEX_UNIT *unit)
{
  for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
  {
    relink_tables(sl);
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    for (SELECT_LEX_UNIT *un= sl->first_inner_unit(); un; un= un->next_unit())
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      fix_tables_pointers(un);
  }
}

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/*
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  Function to setup clauses without sum functions
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*/
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inline int setup_without_group(THD *thd, Item **ref_pointer_array,
			       TABLE_LIST *tables,
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			       List<Item> &fields,
			       List<Item> &all_fields,
			       COND **conds,
			       ORDER *order,
			       ORDER *group, bool *hidden_group_fields)
{
  bool save_allow_sum_func= thd->allow_sum_func;
  thd->allow_sum_func= 0;
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  int res= (setup_conds(thd, tables, conds) ||
	    setup_order(thd, ref_pointer_array, tables, fields, all_fields,
			order) ||
	    setup_group(thd, ref_pointer_array, tables, fields, all_fields,
			group, hidden_group_fields));
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  thd->allow_sum_func= save_allow_sum_func;
  return res;
}

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/*****************************************************************************
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  Check fields, find best join, do the select and output fields.
  mysql_select assumes that all tables are already opened
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*****************************************************************************/

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/*
  Prepare of whole select (including subselect in future).
  return -1 on error
          0 on success
*/
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int
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JOIN::prepare(Item ***rref_pointer_array,
	      TABLE_LIST *tables_init,
	      uint wild_num, COND *conds_init, uint og_num,
	      ORDER *order_init, ORDER *group_init,
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	      Item *having_init,
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	      ORDER *proc_param_init, SELECT_LEX *select_lex_arg,
	      SELECT_LEX_UNIT *unit_arg)
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{
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  DBUG_ENTER("JOIN::prepare");
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  conds= conds_init;
  order= order_init;
  group_list= group_init;
  having= having_init;
  proc_param= proc_param_init;
  tables_list= tables_init;
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  select_lex= select_lex_arg;
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  select_lex->join= this;
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  union_part= (unit_arg->first_select()->next_select() != 0);
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  /* Check that all tables, fields, conds and order are ok */

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  if (setup_tables(tables_list, 0) ||
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      setup_wild(thd, tables_list, fields_list, &all_fields, wild_num) ||
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      select_lex->setup_ref_array(thd, og_num) ||
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      setup_fields(thd, (*rref_pointer_array), tables_list, fields_list, 1,
		   &all_fields, 1) ||
      setup_without_group(thd, (*rref_pointer_array), tables_list, fields_list,
			  all_fields, &conds, order, group_list, 
			  &hidden_group_fields))
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    DBUG_RETURN(-1);				/* purecov: inspected */

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  ref_pointer_array= *rref_pointer_array;
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  if (having)
  {
    thd->where="having clause";
    thd->allow_sum_func=1;
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    select_lex->having_fix_field= 1;
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    bool having_fix_rc= (having->fix_fields(thd, tables_list, &having) ||
			 having->check_cols(1));
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    select_lex->having_fix_field= 0;
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    if (having_fix_rc || thd->net.report_error)
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      DBUG_RETURN(-1);				/* purecov: inspected */
    if (having->with_sum_func)
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      having->split_sum_func(ref_pointer_array, all_fields);
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  }
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  // Is it subselect
  {
    Item_subselect *subselect;
    if ((subselect= select_lex->master_unit()->item) &&
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	select_lex->linkage != GLOBAL_OPTIONS_TYPE)
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    {
      Item_subselect::trans_res res;
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      if ((res= subselect->select_transformer(this)) !=
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	  Item_subselect::RES_OK)
	DBUG_RETURN((res == Item_subselect::RES_ERROR));
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    }
  }

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  if (setup_ftfuncs(select_lex)) /* should be after having->fix_fields */
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    DBUG_RETURN(-1);
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  /*
    Check if one one uses a not constant column with group functions
    and no GROUP BY.
    TODO:  Add check of calculation of GROUP functions and fields:
	   SELECT COUNT(*)+table.col1 from table1;
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  */
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  {
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    if (!group_list)
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    {
      uint flag=0;
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      List_iterator_fast<Item> it(fields_list);
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      Item *item;
      while ((item= it++))
      {
	if (item->with_sum_func)
	  flag|=1;
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	else if (!(flag & 2) && !item->const_item())
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	  flag|=2;
      }
      if (flag == 3)
      {
	my_error(ER_MIX_OF_GROUP_FUNC_AND_FIELDS,MYF(0));
	DBUG_RETURN(-1);
      }
    }
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    TABLE_LIST *table_ptr;
    for (table_ptr= tables_list ; table_ptr ; table_ptr= table_ptr->next)
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      tables++;
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  }
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  {
    /* Caclulate the number of groups */
    send_group_parts= 0;
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    for (ORDER *group_tmp= group_list ; group_tmp ; group_tmp= group_tmp->next)
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      send_group_parts++;
  }
  
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  procedure= setup_procedure(thd, proc_param, result, fields_list, &error);
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  if (error)
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    goto err;					/* purecov: inspected */
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  if (procedure)
  {
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    if (setup_new_fields(thd, tables_list, fields_list, all_fields,
			 procedure->param_fields))
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	goto err;				/* purecov: inspected */
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    if (procedure->group)
    {
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      if (!test_if_subpart(procedure->group,group_list))
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      {						/* purecov: inspected */
	my_message(0,"Can't handle procedures with differents groups yet",
		   MYF(0));			/* purecov: inspected */
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	goto err;				/* purecov: inspected */
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      }
    }
#ifdef NOT_NEEDED
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    else if (!group_list && procedure->flags & PROC_GROUP)
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    {
      my_message(0,"Select must have a group with this procedure",MYF(0));
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      goto err;
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    }
#endif
    if (order && (procedure->flags & PROC_NO_SORT))
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    {						/* purecov: inspected */
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      my_message(0,"Can't use order with this procedure",MYF(0)); /* purecov: inspected */
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      goto err;					/* purecov: inspected */
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    }
  }

  /* Init join struct */
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  count_field_types(&tmp_table_param, all_fields, 0);
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  ref_pointer_array_size= all_fields.elements*sizeof(Item*);
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  this->group= group_list != 0;
  row_limit= ((select_distinct || order || group_list) ? HA_POS_ERROR :
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	      unit_arg->select_limit_cnt);
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  /* select_limit is used to decide if we are likely to scan the whole table */
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  select_limit= unit_arg->select_limit_cnt;
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  if (having || (select_options & OPTION_FOUND_ROWS))
    select_limit= HA_POS_ERROR;
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  do_send_rows = (unit_arg->select_limit_cnt) ? 1 : 0;
  unit= unit_arg;
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#ifdef RESTRICTED_GROUP
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  if (sum_func_count && !group_list && (func_count || field_count))
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  {
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    my_message(ER_WRONG_SUM_SELECT,ER(ER_WRONG_SUM_SELECT),MYF(0));
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    goto err;
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  }
#endif
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  if (!procedure && result->prepare(fields_list, unit_arg))
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    goto err;					/* purecov: inspected */

  if (select_lex->olap == ROLLUP_TYPE && rollup_init())
    goto err;
  if (alloc_func_list())
    goto err;

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  DBUG_RETURN(0); // All OK
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err:
  delete procedure;				/* purecov: inspected */
  procedure= 0;
  DBUG_RETURN(-1);				/* purecov: inspected */
447
}
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/*
  test if it is known for optimisation IN subquery

  SYNOPSYS
    JOIN::test_in_subselect
    where - pointer for variable in which conditions should be
            stored if subquery is known

  RETURN
    1 - known
    0 - unknown
*/

bool JOIN::test_in_subselect(Item **where)
{
  if (conds->type() == Item::FUNC_ITEM &&
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      ((Item_func *)this->conds)->functype() == Item_func::EQ_FUNC &&
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      ((Item_func *)conds)->arguments()[0]->type() == Item::REF_ITEM &&
      ((Item_func *)conds)->arguments()[1]->type() == Item::FIELD_ITEM)
  {
    join_tab->info= "Using index";
    *where= 0;
    return 1;
  }
  if (conds->type() == Item::COND_ITEM &&
      ((class Item_func *)this->conds)->functype() ==
      Item_func::COND_AND_FUNC)
  {
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    if ((*where= remove_additional_cond(conds)))
      join_tab->info= "Using index; Using where";
    else
      join_tab->info= "Using index";
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    return 1;
  }
  return 0;
}


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/*
  global select optimisation.
  return 0 - success
490
         1 - error
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  error code saved in field 'error'
*/
int
JOIN::optimize()
{
  DBUG_ENTER("JOIN::optimize");
497
  // to prevent double initialization on EXPLAIN
498 499 500
  if (optimized)
    DBUG_RETURN(0);
  optimized= 1;
501

502
  // Ignore errors of execution if option IGNORE present
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  if (thd->lex->duplicates == DUP_IGNORE)
    thd->lex->current_select->no_error= 1;
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#ifdef HAVE_REF_TO_FIELDS			// Not done yet
  /* Add HAVING to WHERE if possible */
507
  if (having && !group_list && !sum_func_count)
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  {
    if (!conds)
    {
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      conds= having;
      having= 0;
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    }
    else if ((conds=new Item_cond_and(conds,having)))
    {
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      conds->fix_fields(thd, tables_list, &conds);
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      conds->change_ref_to_fields(thd, tables_list);
518
      conds->top_level_item();
519
      having= 0;
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    }
  }
#endif

524
  conds= optimize_cond(conds,&cond_value);
525
  if (thd->net.report_error)
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  {
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    error= 1;
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    DBUG_PRINT("error",("Error from optimize_cond"));
529
    DBUG_RETURN(1);
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  }
531

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  if (cond_value == Item::COND_FALSE ||
      (!unit->select_limit_cnt && !(select_options & OPTION_FOUND_ROWS)))
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  {						/* Impossible cond */
535
    zero_result_cause= "Impossible WHERE";
536
    error= 0;
537
    DBUG_RETURN(0);
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  }

  /* Optimize count(*), min() and max() */
541
  if (tables_list && tmp_table_param.sum_func_count && ! group_list)
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  {
    int res;
544
    /*
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      opt_sum_query() returns -1 if no rows match to the WHERE conditions,
      or 1 if all items were resolved, or 0, or an error number HA_ERR_...
547
    */
548
    if ((res=opt_sum_query(tables_list, all_fields, conds)))
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    {
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      if (res > 1)
      {
552
	DBUG_RETURN(1);
553
      }
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      if (res < 0)
      {
556
	zero_result_cause= "No matching min/max row";
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	error=0;
558
	DBUG_RETURN(0);
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      }
560
      zero_result_cause= "Select tables optimized away";
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      tables_list= 0;				// All tables resolved
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    }
  }
564
  if (!tables_list)
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  {
    error= 0;
567
    DBUG_RETURN(0);
568
  }
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  error= -1;					// Error is sent to client
570
  sort_by_table= get_sort_by_table(order, group_list, tables_list);
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  /* Calculate how to do the join */
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  thd->proc_info= "statistics";
  if (make_join_statistics(this, tables_list, conds, &keyuse) ||
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      thd->is_fatal_error)
576 577
  {
    DBUG_PRINT("error",("Error: make_join_statistics() failed"));
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    DBUG_RETURN(1);
579
  }
580

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  /* Remove distinct if only const tables */
  select_distinct= select_distinct && (const_tables != tables);
583
  thd->proc_info= "preparing";
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584
  if (result->initialize_tables(this))
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  {
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    DBUG_PRINT("error",("Error: initialize_tables() failed"));
    DBUG_RETURN(1);				// error == -1
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  }
589
  if (const_table_map != found_const_table_map &&
590
      !(select_options & SELECT_DESCRIBE))
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  {
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    zero_result_cause= "no matching row in const table";
593
    DBUG_PRINT("error",("Error: %s", zero_result_cause));
594
    select_options= 0; //TODO why option in return_zero_rows was droped
595
    error= 0;
596
    DBUG_RETURN(0);
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  }
  if (!(thd->options & OPTION_BIG_SELECTS) &&
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      best_read > (double) thd->variables.max_join_size &&
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      !(select_options & SELECT_DESCRIBE))
  {						/* purecov: inspected */
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    my_message(ER_TOO_BIG_SELECT, ER(ER_TOO_BIG_SELECT), MYF(0));
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    error= 1;					/* purecov: inspected */
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    DBUG_RETURN(1);
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  }
606
  if (const_tables && !thd->locked_tables &&
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607
      !(select_options & SELECT_NO_UNLOCK))
608
  {
609
    TABLE **curr_table, **end;
610
    for (curr_table= table, end=curr_table + const_tables ;
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	 curr_table != end;
	 curr_table++)
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    {
      /* BDB tables require that we call index_end() before doing an unlock */
615
      if ((*curr_table)->key_read)
616
      {
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	(*curr_table)->key_read=0;
	(*curr_table)->file->extra(HA_EXTRA_NO_KEYREAD);
619
      }
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      (*curr_table)->file->index_end();
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    }
622
    mysql_unlock_some_tables(thd, table, const_tables);
623
  }
624
  if (!conds && outer_join)
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  {
    /* Handle the case where we have an OUTER JOIN without a WHERE */
    conds=new Item_int((longlong) 1,1);	// Always true
  }
629 630
  select=make_select(*table, const_table_map,
		     const_table_map, conds, &error);
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  if (error)
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  {						/* purecov: inspected */
    error= -1;					/* purecov: inspected */
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    DBUG_PRINT("error",("Error: make_select() failed"));
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    DBUG_RETURN(1);
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  }
637
  if (make_join_select(this, select, conds))
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  {
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    zero_result_cause=
      "Impossible WHERE noticed after reading const tables";
641
    DBUG_RETURN(0);				// error == 0
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  }

  error= -1;					/* if goto err */

  /* Optimize distinct away if possible */
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  {
    ORDER *org_order= order;
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    order=remove_const(this, order,conds,&simple_order);
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    /*
      If we are using ORDER BY NULL or ORDER BY const_expression,
      return result in any order (even if we are using a GROUP BY)
    */
    if (!order && org_order)
      skip_sort_order= 1;
  }
657 658
  order= remove_const(this, order, conds, &simple_order);
  if (group_list || tmp_table_param.sum_func_count)
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  {
    if (! hidden_group_fields)
      select_distinct=0;
  }
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  else if (select_distinct && tables - const_tables == 1)
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  {
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    /*
      We are only using one table. In this case we change DISTINCT to a
      GROUP BY query if:
      - The GROUP BY can be done through indexes (no sort) and the ORDER
        BY only uses selected fields.
	(In this case we can later optimize away GROUP BY and ORDER BY)
      - We are scanning the whole table without LIMIT
        This can happen if:
        - We are using CALC_FOUND_ROWS
        - We are using an ORDER BY that can't be optimized away.

      We don't want to use this optimization when we are using LIMIT
      because in this case we can just create a temporary table that
      holds LIMIT rows and stop when this table is full.
    */
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    JOIN_TAB *tab= &join_tab[const_tables];
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    bool all_order_fields_used;
    if (order)
      skip_sort_order= test_if_skip_sort_order(tab, order, select_limit, 1);
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    if ((group_list=create_distinct_group(thd, order, fields_list,
				          &all_order_fields_used)))
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    {
      bool skip_group= (skip_sort_order &&
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			test_if_skip_sort_order(tab, group_list, select_limit,
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						1) != 0);
      if ((skip_group && all_order_fields_used) ||
	  select_limit == HA_POS_ERROR ||
	  (order && !skip_sort_order))
      {
	/*  Change DISTINCT to GROUP BY */
	select_distinct= 0;
	no_order= !order;
	if (all_order_fields_used)
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	{
	  if (order && skip_sort_order)
	  {
	    /*
	      Force MySQL to read the table in sorted order to get result in
	      ORDER BY order.
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	    */
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	    tmp_table_param.quick_group=0;
706
	  }
707
	  order=0;
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        }
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	group=1;				// For end_write_group
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      }
      else
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	group_list= 0;
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    }
714
    else if (thd->is_fatal_error)			// End of memory
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      DBUG_RETURN(1);
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  }
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  simple_group= 0;
  if (rollup.state == ROLLUP::STATE_NONE)
    group_list= remove_const(this, group_list, conds, &simple_group);
720
  if (!group_list && group)
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  {
    order=0;					// The output has only one row
    simple_order=1;
  }

726 727
  calc_group_buffer(this, group_list);
  send_group_parts= tmp_table_param.group_parts; /* Save org parts */
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  if (procedure && procedure->group)
  {
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    group_list= procedure->group= remove_const(this, procedure->group, conds,
					       &simple_group);
    calc_group_buffer(this, group_list);
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  }

735 736
  if (test_if_subpart(group_list, order) ||
      (!group_list && tmp_table_param.sum_func_count))
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    order=0;

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  // Can't use sort on head table if using row cache
740
  if (full_join)
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  {
742
    if (group_list)
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      simple_group=0;
    if (order)
      simple_order=0;
  }

748 749 750 751 752 753 754 755 756
  /*
    Check if we need to create a temporary table.
    This has to be done if all tables are not already read (const tables)
    and one of the following conditions holds:
    - We are using DISTINCT (simple distinct's are already optimized away)
    - We are using an ORDER BY or GROUP BY on fields not in the first table
    - We are using different ORDER BY and GROUP BY orders
    - The user wants us to buffer the result.
  */
757
  need_tmp= (const_tables != tables &&
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	     ((select_distinct || !simple_order || !simple_group) ||
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	      (group_list && order) ||
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	      test(select_options & OPTION_BUFFER_RESULT)));
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762
  // No cache for MATCH
763
  make_join_readinfo(this,
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		     (select_options & (SELECT_DESCRIBE |
765
					SELECT_NO_JOIN_CACHE)) |
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		     (select_lex->ftfunc_list->elements ?
767
		      SELECT_NO_JOIN_CACHE : 0));
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  /*
    is this simple IN subquery?
  */
772
  if (!group_list && !order &&
773
      unit->item && unit->item->substype() == Item_subselect::IN_SUBS &&
774
      tables == 1 && conds &&
775 776
      !unit->first_select()->next_select())
  {
777
    if (!having)
778
    {
779
      Item *where= 0;
780 781
      if (join_tab[0].type == JT_EQ_REF &&
	  join_tab[0].ref.items[0]->name == in_left_expr_name)
782
      {
783 784
	if (test_in_subselect(&where))
	{
785
	  join_tab[0].type= JT_UNIQUE_SUBQUERY;
786 787
	  error= 0;
	  DBUG_RETURN(unit->item->
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		      change_engine(new
				    subselect_uniquesubquery_engine(thd,
								    join_tab,
								    unit->item,
								    where)));
793
	}
794
      }
795 796
      else if (join_tab[0].type == JT_REF &&
	       join_tab[0].ref.items[0]->name == in_left_expr_name)
797
      {
798 799
	if (test_in_subselect(&where))
	{
800
	  join_tab[0].type= JT_INDEX_SUBQUERY;
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	  error= 0;
	  DBUG_RETURN(unit->item->
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		      change_engine(new
				    subselect_indexsubquery_engine(thd,
								   join_tab,
								   unit->item,
								   where,
								   0)));
809
	}
810
      }
811
    } else if (join_tab[0].type == JT_REF_OR_NULL &&
812
	       join_tab[0].ref.items[0]->name == in_left_expr_name &&
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	       having->type() == Item::FUNC_ITEM &&
	       ((Item_func *) having)->functype() ==
	       Item_func::ISNOTNULLTEST_FUNC)
    {
817
      join_tab[0].type= JT_INDEX_SUBQUERY;
818
      error= 0;
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      if ((conds= remove_additional_cond(conds)))
	join_tab->info= "Using index; Using where";
      else
	join_tab->info= "Using index";
 
825
      DBUG_RETURN(unit->item->
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		  change_engine(new subselect_indexsubquery_engine(thd,
								   join_tab,
								   unit->item,
								   conds,
								   1)));
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    }
832

833
  }
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  /*
    Need to tell Innobase that to play it safe, it should fetch all
    columns of the tables: this is because MySQL may build row
    pointers for the rows, and for all columns of the primary key the
    field->query_id has not necessarily been set to thd->query_id by
    MySQL.
  */
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#ifdef HAVE_INNOBASE_DB
843
  if (need_tmp || select_distinct || group_list || order)
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  {
845
    for (uint i_h = const_tables; i_h < tables; i_h++)
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    {
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      TABLE* table_h = join_tab[i_h].table;
848
      if (table_h->db_type == DB_TYPE_INNODB)
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	table_h->file->extra(HA_EXTRA_RETRIEVE_ALL_COLS);
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    }
  }
#endif

854
  DBUG_EXECUTE("info",TEST_join(this););
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  /*
    Because filesort always does a full table scan or a quick range scan
    we must add the removed reference to the select for the table.
    We only need to do this when we have a simple_order or simple_group
    as in other cases the join is done before the sort.
860
  */
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  if (const_tables != tables &&
      (order || group_list) && join_tab[const_tables].type != JT_ALL &&
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      join_tab[const_tables].type != JT_FT &&
      (order && simple_order || group_list && simple_group))
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  {
866
    if (add_ref_to_table_cond(thd,&join_tab[const_tables]))
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      DBUG_RETURN(1);
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  }

  if (!(select_options & SELECT_BIG_RESULT) &&
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      ((group_list && const_tables != tables &&
872
	(!simple_group ||
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	 !test_if_skip_sort_order(&join_tab[const_tables], group_list,
				  unit->select_limit_cnt,
				  0))) ||
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       select_distinct) &&
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      tmp_table_param.quick_group && !procedure)
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  {
    need_tmp=1; simple_order=simple_group=0;	// Force tmp table without sort
  }
881

882
  tmp_having= having;
883
  if (select_options & SELECT_DESCRIBE)
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  {
    error= 0;
886
    DBUG_RETURN(0);
887
  }
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  having= 0;

  /* Perform FULLTEXT search before all regular searches */
  init_ftfuncs(thd, select_lex, test(order));
  /* Create a tmp table if distinct or if the sort is too complicated */
  if (need_tmp)
  {
    DBUG_PRINT("info",("Creating tmp table"));
    thd->proc_info="Creating tmp table";

    init_items_ref_array();
    
    tmp_table_param.hidden_field_count= (all_fields.elements -
					 fields_list.elements);
    if (!(exec_tmp_table1 =
	  create_tmp_table(thd, &tmp_table_param, all_fields,
			   ((!simple_group && !procedure &&
			     !(test_flags & TEST_NO_KEY_GROUP)) ?
			    group_list : (ORDER*) 0),
			   group_list ? 0 : select_distinct,
			   group_list && simple_group,
			   select_options,
			   (order == 0 || skip_sort_order) ? select_limit :
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			   HA_POS_ERROR,
			   (char *) "")))
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      DBUG_RETURN(1);
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    /*
      We don't have to store rows in temp table that doesn't match HAVING if:
      - we are sorting the table and writing complete group rows to the
        temp table.
      - We are using DISTINCT without resolving the distinct as a GROUP BY
        on all columns.
      
      If having is not handled here, it will be checked before the row
      is sent to the client.
    */    
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    if (having && 
	(sort_and_group || (exec_tmp_table1->distinct && !group_list)))
      having= tmp_having;

    /* if group or order on first table, sort first */
    if (group_list && simple_group)
    {
      DBUG_PRINT("info",("Sorting for group"));
      thd->proc_info="Sorting for group";
934
      if (create_sort_index(thd, this, group_list,
935
			    HA_POS_ERROR, HA_POS_ERROR) ||
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	  alloc_group_fields(this, group_list) ||
	  make_sum_func_list(all_fields, fields_list, 1))
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	DBUG_RETURN(1);
      group_list=0;
    }
    else
    {
943
      if (make_sum_func_list(all_fields, fields_list, 0))
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	DBUG_RETURN(1);
      if (!group_list && ! exec_tmp_table1->distinct && order && simple_order)
      {
	DBUG_PRINT("info",("Sorting for order"));
	thd->proc_info="Sorting for order";
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	if (create_sort_index(thd, this, order,
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                              HA_POS_ERROR, HA_POS_ERROR))
	  DBUG_RETURN(1);
	order=0;
      }
    }
    
    /*
      Optimize distinct when used on some of the tables
      SELECT DISTINCT t1.a FROM t1,t2 WHERE t1.b=t2.b
      In this case we can stop scanning t2 when we have found one t1.a
    */

    if (exec_tmp_table1->distinct)
    {
      table_map used_tables= thd->used_tables;
965
      JOIN_TAB *last_join_tab= join_tab+tables-1;
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      do
      {
968
	if (used_tables & last_join_tab->table->map)
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	  break;
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	last_join_tab->not_used_in_distinct=1;
      } while (last_join_tab-- != join_tab);
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      /* Optimize "select distinct b from t1 order by key_part_1 limit #" */
      if (order && skip_sort_order)
      {
 	/* Should always succeed */
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	if (test_if_skip_sort_order(&join_tab[const_tables],
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				    order, unit->select_limit_cnt, 0))
	  order=0;
      }
    }
    
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    if (select_lex->master_unit()->uncacheable)
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    {
      if (!(tmp_join= (JOIN*)thd->alloc(sizeof(JOIN))))
	DBUG_RETURN(-1);
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      error= 0;				// Ensure that tmp_join.error= 0
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      restore_tmp();
    }
  }

991
  error= 0;
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  DBUG_RETURN(0);
}

995

996
/*
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  Restore values in temporary join
998
*/
999
void JOIN::restore_tmp()
1000
{
1001
  memcpy(tmp_join, this, (size_t) sizeof(JOIN));
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}

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int
JOIN::reinit()
{
  DBUG_ENTER("JOIN::reinit");
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  /* TODO move to unit reinit */
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  unit->offset_limit_cnt =select_lex->offset_limit;
  unit->select_limit_cnt =select_lex->select_limit+select_lex->offset_limit;
  if (unit->select_limit_cnt < select_lex->select_limit)
    unit->select_limit_cnt= HA_POS_ERROR;		// no limit
  if (unit->select_limit_cnt == HA_POS_ERROR)
    select_lex->options&= ~OPTION_FOUND_ROWS;
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1016
  
1017
  if (setup_tables(tables_list, 1))
1018
    DBUG_RETURN(1);
1019
  
1020
  /* Reset of sum functions */
1021
  first_record= 0;
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  if (exec_tmp_table1)
  {
    exec_tmp_table1->file->extra(HA_EXTRA_RESET_STATE);
    exec_tmp_table1->file->delete_all_rows();
    free_io_cache(exec_tmp_table1);
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    filesort_free_buffers(exec_tmp_table1);
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  }
  if (exec_tmp_table2)
  {
    exec_tmp_table2->file->extra(HA_EXTRA_RESET_STATE);
    exec_tmp_table2->file->delete_all_rows();
    free_io_cache(exec_tmp_table2);
1035
    filesort_free_buffers(exec_tmp_table2);
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  }
  if (items0)
1038
    set_items_ref_array(items0);
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  if (join_tab_save)
    memcpy(join_tab, join_tab_save, sizeof(JOIN_TAB) * tables);

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  if (tmp_join)
    restore_tmp();

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  DBUG_RETURN(0);
}

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bool
JOIN::save_join_tab()
{
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  if (!join_tab_save && select_lex->master_unit()->uncacheable)
1054
  {
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    if (!(join_tab_save= (JOIN_TAB*)thd->memdup((gptr) join_tab,
						sizeof(JOIN_TAB) * tables)))
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      return 1;
  }
  return 0;
}


1063
/*
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  Exec select
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*/
void
JOIN::exec()
{
  int      tmp_error;
  DBUG_ENTER("JOIN::exec");
1071
  
1072
  error= 0;
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1073
  thd->limit_found_rows= thd->examined_row_count= 0;
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  if (procedure)
  {
    if (procedure->change_columns(fields_list) ||
	result->prepare(fields_list, unit))
      DBUG_VOID_RETURN;
  }
1080

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1081
  if (!tables_list)
1082 1083
  {                                           // Only test of functions
    if (select_options & SELECT_DESCRIBE)
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      select_describe(this, false, false, false,
		      (zero_result_cause?zero_result_cause:"No tables used"));
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    else
    {
      result->send_fields(fields_list,1);
      if (!having || having->val_int())
      {
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	if (do_send_rows && (procedure ? (procedure->send_row(fields_list) ||
                                          procedure->end_of_records())
                                       : result->send_data(fields_list)))
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	  error= 1;
1095
	else
1096
	{
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	  error= (int) result->send_eof();
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	  send_records=1;
	}
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      }
      else
1102
	error=(int) result->send_eof();
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    }
    DBUG_VOID_RETURN;
  }

  if (zero_result_cause)
  {
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    (void) return_zero_rows(this, result, tables_list, fields_list,
			    tmp_table_param.sum_func_count != 0 &&
			    !group_list,
			    select_options,
			    zero_result_cause,
1114
			    having, procedure,
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1115
			    unit);
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    DBUG_VOID_RETURN;
  }

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  if (select_options & SELECT_DESCRIBE)
  {
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    /*
      Check if we managed to optimize ORDER BY away and don't use temporary
      table to resolve ORDER BY: in that case, we only may need to do
      filesort for GROUP BY.
    */
    if (!order && !no_order && (!skip_sort_order || !need_tmp))
    {
      /*
	Reset 'order' to 'group_list' and reinit variables describing
	'order'
      */
      order= group_list;
      simple_order= simple_group;
      skip_sort_order= 0;
    }
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    if (order &&
1137
	(const_tables == tables ||
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1138
 	 ((simple_order || skip_sort_order) &&
1139
	  test_if_skip_sort_order(&join_tab[const_tables], order,
1140
				  select_limit, 0))))
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1141
      order=0;
1142
    having= tmp_having;
1143
    select_describe(this, need_tmp,
1144
		    order != 0 && !skip_sort_order,
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1145
		    select_distinct);
1146
    DBUG_VOID_RETURN;
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  }

1149 1150 1151 1152
  JOIN *curr_join= this;
  List<Item> *curr_all_fields= &all_fields;
  List<Item> *curr_fields_list= &fields_list;
  TABLE *curr_tmp_table= 0;
1153

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1154 1155 1156
  /* Create a tmp table if distinct or if the sort is too complicated */
  if (need_tmp)
  {
1157 1158 1159
    if (tmp_join)
      curr_join= tmp_join;
    curr_tmp_table= exec_tmp_table1;
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1160 1161

    /* Copy data to the temporary table */
1162
    thd->proc_info= "Copying to tmp table";
1163 1164
    
    if ((tmp_error= do_select(curr_join, (List<Item> *) 0, curr_tmp_table, 0)))
1165
    {
1166 1167
      error= tmp_error;
      DBUG_VOID_RETURN;
1168
    }
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    curr_tmp_table->file->info(HA_STATUS_VARIABLE);
    
    if (curr_join->having)
      curr_join->having= curr_join->tmp_having= 0; // Allready done
    
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    /* Change sum_fields reference to calculated fields in tmp_table */
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    curr_join->all_fields= *curr_all_fields;
    if (!items1)
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    {
1178 1179 1180
      items1= items0 + all_fields.elements;
      if (sort_and_group || curr_tmp_table->group)
      {
1181
	if (change_to_use_tmp_fields(thd, items1,
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				     tmp_fields_list1, tmp_all_fields1,
				     fields_list.elements, all_fields))
	  DBUG_VOID_RETURN;
      }
      else
      {
	if (change_refs_to_tmp_fields(thd, items1,
				      tmp_fields_list1, tmp_all_fields1,
				      fields_list.elements, all_fields))
	  DBUG_VOID_RETURN;
      }
      curr_join->tmp_all_fields1= tmp_all_fields1;
      curr_join->tmp_fields_list1= tmp_fields_list1;
      curr_join->items1= items1;
    }
    curr_all_fields= &tmp_all_fields1;
    curr_fields_list= &tmp_fields_list1;
1199
    set_items_ref_array(items1);
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    if (sort_and_group || curr_tmp_table->group)
    {
      curr_join->tmp_table_param.field_count+= 
	curr_join->tmp_table_param.sum_func_count+
	curr_join->tmp_table_param.func_count;
      curr_join->tmp_table_param.sum_func_count= 
	curr_join->tmp_table_param.func_count= 0;
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    }
    else
    {
1211 1212 1213
      curr_join->tmp_table_param.field_count+= 
	curr_join->tmp_table_param.func_count;
      curr_join->tmp_table_param.func_count= 0;
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    }
1215 1216
    
    // procedure can't be used inside subselect => we do nothing special for it
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    if (procedure)
      procedure->update_refs();
1219 1220
    
    if (curr_tmp_table->group)
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1221
    {						// Already grouped
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1222
      if (!curr_join->order && !curr_join->no_order && !skip_sort_order)
1223 1224
	curr_join->order= curr_join->group_list;  /* order by group */
      curr_join->group_list= 0;
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    }
1226
    
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1227
    /*
1228 1229 1230 1231 1232
      If we have different sort & group then we must sort the data by group
      and copy it to another tmp table
      This code is also used if we are using distinct something
      we haven't been able to store in the temporary table yet
      like SEC_TO_TIME(SUM(...)).
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    */

1235 1236 1237 1238 1239
    if (curr_join->group_list && (!test_if_subpart(curr_join->group_list,
						   curr_join->order) || 
				  curr_join->select_distinct) ||
	(curr_join->select_distinct &&
	 curr_join->tmp_table_param.using_indirect_summary_function))
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    {					/* Must copy to another table */
      DBUG_PRINT("info",("Creating group table"));
1242
      
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1243
      /* Free first data from old join */
1244
      curr_join->join_free(0);
1245
      if (make_simple_join(curr_join, curr_tmp_table))
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1246
	DBUG_VOID_RETURN;
1247
      calc_group_buffer(curr_join, group_list);
1248 1249
      count_field_types(&curr_join->tmp_table_param,
			curr_join->tmp_all_fields1,
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			curr_join->select_distinct && !curr_join->group_list);
      curr_join->tmp_table_param.hidden_field_count= 
	(curr_join->tmp_all_fields1.elements-
	 curr_join->tmp_fields_list1.elements);
      
      
      if (exec_tmp_table2)
	curr_tmp_table= exec_tmp_table2;
      else
      {
	/* group data to new table */
	if (!(curr_tmp_table=
	      exec_tmp_table2= create_tmp_table(thd,
						&curr_join->tmp_table_param,
						*curr_all_fields,
						(ORDER*) 0,
						curr_join->select_distinct && 
						!curr_join->group_list,
						1, curr_join->select_options,
1269 1270
						HA_POS_ERROR,
						(char *) "")))
1271 1272 1273
	  DBUG_VOID_RETURN;
	curr_join->exec_tmp_table2= exec_tmp_table2;
      }
1274
      if (curr_join->group_list)
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      {
1276
	thd->proc_info= "Creating sort index";
1277 1278 1279 1280
	if (curr_join->join_tab == join_tab && save_join_tab())
	{
	  DBUG_VOID_RETURN;
	}
1281
	if (create_sort_index(thd, curr_join, curr_join->group_list,
1282
			      HA_POS_ERROR, HA_POS_ERROR) ||
1283
	    make_group_fields(this, curr_join))
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	{
1285
	  DBUG_VOID_RETURN;
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	}
1287
	curr_join->group_list= 0;
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      }
1289
      
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      thd->proc_info="Copying to group table";
1291
      tmp_error= -1;
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      if (curr_join != this)
      {
	if (sum_funcs2)
	{
	  curr_join->sum_funcs= sum_funcs2;
	  curr_join->sum_funcs_end= sum_funcs_end2; 
	}
	else
	{
	  curr_join->alloc_func_list();
	  sum_funcs2= curr_join->sum_funcs;
	  sum_funcs_end2= curr_join->sum_funcs_end;
	}
      }
1306 1307
      if (curr_join->make_sum_func_list(*curr_all_fields, *curr_fields_list,
					1) ||
1308 1309
	  (tmp_error= do_select(curr_join, (List<Item> *) 0, curr_tmp_table,
				0)))
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      {
1311
	error= tmp_error;
1312
	DBUG_VOID_RETURN;
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      }
1314 1315 1316 1317 1318 1319 1320 1321
      end_read_record(&curr_join->join_tab->read_record);
      curr_join->const_tables= curr_join->tables; // Mark free for join_free()
      curr_join->join_tab[0].table= 0;           // Table is freed
      
      // No sum funcs anymore
      if (!items2)
      {
	items2= items1 + all_fields.elements;
1322
	if (change_to_use_tmp_fields(thd, items2,
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				     tmp_fields_list2, tmp_all_fields2, 
				     fields_list.elements, tmp_all_fields1))
	  DBUG_VOID_RETURN;
	curr_join->tmp_fields_list2= tmp_fields_list2;
	curr_join->tmp_all_fields2= tmp_all_fields2;
      }
      curr_fields_list= &curr_join->tmp_fields_list2;
      curr_all_fields= &curr_join->tmp_all_fields2;
1331
      set_items_ref_array(items2);
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      curr_join->tmp_table_param.field_count+= 
	curr_join->tmp_table_param.sum_func_count;
      curr_join->tmp_table_param.sum_func_count= 0;
    }
    if (curr_tmp_table->distinct)
      curr_join->select_distinct=0;		/* Each row is unique */
    
1339
    curr_join->join_free(0);			/* Free quick selects */
1340
    if (select_distinct && ! group_list)
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    {
      thd->proc_info="Removing duplicates";
1343 1344 1345 1346
      if (curr_join->tmp_having)
	curr_join->tmp_having->update_used_tables();
      if (remove_duplicates(curr_join, curr_tmp_table,
			    curr_join->fields_list, curr_join->tmp_having))
1347
	DBUG_VOID_RETURN;
1348 1349
      curr_join->tmp_having=0;
      curr_join->select_distinct=0;
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    }
1351 1352
    curr_tmp_table->reginfo.lock_type= TL_UNLOCK;
    if (make_simple_join(curr_join, curr_tmp_table))
1353
      DBUG_VOID_RETURN;
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    calc_group_buffer(curr_join, curr_join->group_list);
    count_field_types(&curr_join->tmp_table_param, *curr_all_fields, 0);
    
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1357 1358
  }
  if (procedure)
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    count_field_types(&curr_join->tmp_table_param, *curr_all_fields, 0);
  
  if (curr_join->group || curr_join->tmp_table_param.sum_func_count ||
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      (procedure && (procedure->flags & PROC_GROUP)))
  {
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    if (make_group_fields(this, curr_join))
    {
      DBUG_VOID_RETURN;
    }
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    if (!items3)
    {
      if (!items0)
	init_items_ref_array();
      items3= ref_pointer_array + (all_fields.elements*4);
      setup_copy_fields(thd, &curr_join->tmp_table_param,
			items3, tmp_fields_list3, tmp_all_fields3,
			curr_fields_list->elements, *curr_all_fields);
      tmp_table_param.save_copy_funcs= curr_join->tmp_table_param.copy_funcs;
      tmp_table_param.save_copy_field= curr_join->tmp_table_param.copy_field;
      tmp_table_param.save_copy_field_end=
	curr_join->tmp_table_param.copy_field_end;
      curr_join->tmp_all_fields3= tmp_all_fields3;
      curr_join->tmp_fields_list3= tmp_fields_list3;
    }
    else
    {
      curr_join->tmp_table_param.copy_funcs= tmp_table_param.save_copy_funcs;
      curr_join->tmp_table_param.copy_field= tmp_table_param.save_copy_field;
      curr_join->tmp_table_param.copy_field_end=
	tmp_table_param.save_copy_field_end;
    }
    curr_fields_list= &tmp_fields_list3;
    curr_all_fields= &tmp_all_fields3;
1392
    set_items_ref_array(items3);
1393

1394 1395
    if (curr_join->make_sum_func_list(*curr_all_fields, *curr_fields_list,
				      1) || thd->is_fatal_error)
1396
      DBUG_VOID_RETURN;
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  }
1398
  if (curr_join->group_list || curr_join->order)
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  {
    DBUG_PRINT("info",("Sorting for send_fields"));
    thd->proc_info="Sorting result";
    /* If we have already done the group, add HAVING to sorted table */
1403 1404
    if (curr_join->tmp_having && ! curr_join->group_list && 
	! curr_join->sort_and_group)
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1405
    {
1406 1407
      // Some tables may have been const
      curr_join->tmp_having->update_used_tables();
1408 1409 1410
      JOIN_TAB *curr_table= &curr_join->join_tab[curr_join->const_tables];
      table_map used_tables= (curr_join->const_table_map |
			      curr_table->table->map);
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1411

1412 1413
      Item* sort_table_cond= make_cond_for_table(curr_join->tmp_having,
						 used_tables,
1414
						 used_tables);
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1415 1416
      if (sort_table_cond)
      {
1417 1418
	if (!curr_table->select)
	  if (!(curr_table->select= new SQL_SELECT))
1419
	    DBUG_VOID_RETURN;
1420 1421
	if (!curr_table->select->cond)
	  curr_table->select->cond= sort_table_cond;
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1422
	else					// This should never happen
1423 1424
	  if (!(curr_table->select->cond=
		new Item_cond_and(curr_table->select->cond, sort_table_cond)))
1425
	    DBUG_VOID_RETURN;
1426
	curr_table->select_cond= curr_table->select->cond;
1427 1428
	curr_table->select_cond->top_level_item();
	DBUG_EXECUTE("where",print_where(curr_table->select->cond,
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1429
					 "select and having"););
1430 1431 1432
	curr_join->tmp_having= make_cond_for_table(curr_join->tmp_having,
						   ~ (table_map) 0,
						   ~used_tables);
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1433 1434 1435
	DBUG_EXECUTE("where",print_where(conds,"having after sort"););
      }
    }
1436
    {
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1437
      if (group)
1438
	curr_join->select_limit= HA_POS_ERROR;
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1439
      else
1440
      {
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1441 1442 1443 1444
	/*
	  We can abort sorting after thd->select_limit rows if we there is no
	  WHERE clause for any tables after the sorted one.
	*/
1445
	JOIN_TAB *curr_table= &curr_join->join_tab[curr_join->const_tables+1];
1446
	JOIN_TAB *end_table= &curr_join->join_tab[tables];
1447
	for (; curr_table < end_table ; curr_table++)
1448
	{
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1449 1450 1451 1452 1453 1454
	  /*
	    table->keyuse is set in the case there was an original WHERE clause
	    on the table that was optimized away.
	    table->on_expr tells us that it was a LEFT JOIN and there will be
	    at least one row generated from the table.
	  */
1455 1456
	  if (curr_table->select_cond ||
	      (curr_table->keyuse && !curr_table->on_expr))
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1457 1458
	  {
	    /* We have to sort all rows */
1459
	    curr_join->select_limit= HA_POS_ERROR;
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1460 1461
	    break;
	  }
1462 1463
	}
      }
1464 1465 1466 1467
      if (curr_join->join_tab == join_tab && save_join_tab())
      {
	DBUG_VOID_RETURN;
      }
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1468 1469 1470 1471 1472 1473 1474 1475 1476
      /*
	Here we sort rows for ORDER BY/GROUP BY clause, if the optimiser
	chose FILESORT to be faster than INDEX SCAN or there is no 
	suitable index present.
	Note, that create_sort_index calls test_if_skip_sort_order and may
	finally replace sorting with index scan if there is a LIMIT clause in
	the query. XXX: it's never shown in EXPLAIN!
	OPTION_FOUND_ROWS supersedes LIMIT and is taken into account.
      */
1477
      if (create_sort_index(thd, curr_join,
1478 1479
			    curr_join->group_list ? 
			    curr_join->group_list : curr_join->order,
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1480 1481 1482
			    curr_join->select_limit,
			    (select_options & OPTION_FOUND_ROWS ?
			     HA_POS_ERROR : unit->select_limit_cnt)))
1483
	DBUG_VOID_RETURN;
1484
    }
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1485
  }
1486
  curr_join->having= curr_join->tmp_having;
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  thd->proc_info="Sending data";
1488
  error= thd->net.report_error ||
1489
    do_select(curr_join, curr_fields_list, NULL, procedure);
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1490 1491
  thd->limit_found_rows= curr_join->send_records;
  thd->examined_row_count= curr_join->examined_rows;
1492 1493
  DBUG_VOID_RETURN;
}
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1494

1495

1496 1497 1498 1499 1500
/*
  Clean up join. Return error that hold JOIN.
*/

int
1501
JOIN::cleanup()
1502
{
1503
  DBUG_ENTER("JOIN::cleanup");
1504 1505 1506
  select_lex->join= 0;

  if (tmp_join)
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1507 1508 1509 1510 1511 1512
  {
    if (join_tab != tmp_join->join_tab)
    {
      JOIN_TAB *tab, *end;
      for (tab= join_tab, end= tab+tables ; tab != end ; tab++)
      {
1513 1514 1515 1516
	delete tab->select;
	delete tab->quick;
	tab->select=0;
	tab->quick=0;
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1517
	x_free(tab->cache.buff);
1518
	tab->cache.buff= 0;
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1519 1520 1521
      }
    }
    tmp_join->tmp_join= 0;
1522
    DBUG_RETURN(tmp_join->cleanup());
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1523
  }
1524

1525
  lock=0;                                     // It's faster to unlock later
1526
  join_free(1);
1527 1528 1529 1530
   if (exec_tmp_table1)
     free_tmp_table(thd, exec_tmp_table1);
   if (exec_tmp_table2)
     free_tmp_table(thd, exec_tmp_table2);
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1531 1532 1533
  delete select;
  delete_dynamic(&keyuse);
  delete procedure;
1534 1535 1536
  for (SELECT_LEX_UNIT *lex_unit= select_lex->first_inner_unit();
       lex_unit != 0;
       lex_unit= lex_unit->next_unit())
1537
  {
1538
    error|= lex_unit->cleanup();
1539 1540
  }
  DBUG_RETURN(error);
1541 1542
}

1543

1544
int
1545
mysql_select(THD *thd, Item ***rref_pointer_array,
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1546
	     TABLE_LIST *tables, uint wild_num, List<Item> &fields,
1547 1548 1549
	     COND *conds, uint og_num,  ORDER *order, ORDER *group,
	     Item *having, ORDER *proc_param, ulong select_options,
	     select_result *result, SELECT_LEX_UNIT *unit,
1550
	     SELECT_LEX *select_lex)
1551
{
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1552 1553
  int err;
  bool free_join= 1;
1554 1555
  DBUG_ENTER("mysql_select");

1556
  JOIN *join;
1557
  if (select_lex->join != 0)
1558
  {
1559
    join= select_lex->join;
1560 1561 1562
    // is it single SELECT in derived table, called in derived table creation
    if (select_lex->linkage != DERIVED_TABLE_TYPE ||
	(select_options & SELECT_DESCRIBE))
1563
    {
1564
      if (select_lex->linkage != GLOBAL_OPTIONS_TYPE)
1565
      {
1566 1567 1568 1569 1570 1571
	//here is EXPLAIN of subselect or derived table
	join->result= result;
	if (!join->procedure && result->prepare(join->fields_list, unit))
	{
	  DBUG_RETURN(-1);
	}
1572
      }
1573
      else
1574
      {
1575 1576 1577 1578 1579 1580
	if (join->prepare(rref_pointer_array, tables, wild_num,
			  conds, og_num, order, group, having, proc_param,
			  select_lex, unit))
	{
	  goto err;
	}
1581
      }
1582
    }
1583
    free_join= 0;
1584
    join->select_options= select_options;
1585
  }
1586 1587
  else
  {
1588 1589
    if (!(join= new JOIN(thd, fields, select_options, result)))
	DBUG_RETURN(-1);
1590 1591
    thd->proc_info="init";
    thd->used_tables=0;                         // Updated by setup_fields
1592 1593
    if (join->prepare(rref_pointer_array, tables, wild_num,
		      conds, og_num, order, group, having, proc_param,
1594
		      select_lex, unit))
1595
    {
1596
      goto err;
1597 1598 1599
    }
  }

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1600
  if ((err= join->optimize()))
1601
  {
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    goto err;					// 1
  }
1604

1605
  if (thd->lex->describe & DESCRIBE_EXTENDED)
1606 1607 1608 1609 1610
  {
    join->conds_history= join->conds;
    join->having_history= (join->having?join->having:join->tmp_having);
  }

1611
  if (thd->net.report_error)
1612 1613 1614 1615
    goto err;

  join->exec();

1616
  if (thd->lex->describe & DESCRIBE_EXTENDED)
1617 1618 1619 1620 1621
  {
    select_lex->where= join->conds_history;
    select_lex->having= join->having_history;
  }

1622
err:
1623 1624 1625
  if (free_join)
  {
    thd->proc_info="end";
1626
    err= join->cleanup();
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1627 1628
    if (thd->net.report_error)
      err= -1;
1629
    delete join;
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1630
    DBUG_RETURN(err);
1631
  }
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1632
  DBUG_RETURN(join->error);
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1633 1634 1635
}

/*****************************************************************************
1636 1637
  Create JOIN_TABS, make a guess about the table types,
  Approximate how many records will be used in each table
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1638 1639
*****************************************************************************/

1640 1641
static ha_rows get_quick_record_count(THD *thd, SQL_SELECT *select,
				      TABLE *table,
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1642
				      const key_map *keys,ha_rows limit)
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1643 1644 1645 1646 1647 1648 1649
{
  int error;
  DBUG_ENTER("get_quick_record_count");
  if (select)
  {
    select->head=table;
    table->reginfo.impossible_range=0;
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1650
    if ((error=select->test_quick_select(thd, *(key_map *)keys,(table_map) 0,limit))
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1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
	== 1)
      DBUG_RETURN(select->quick->records);
    if (error == -1)
    {
      table->reginfo.impossible_range=1;
      DBUG_RETURN(0);
    }
    DBUG_PRINT("warning",("Couldn't use record count on const keypart"));
  }
  DBUG_RETURN(HA_POS_ERROR);			/* This shouldn't happend */
}


1664 1665 1666 1667 1668 1669 1670
/*
  Calculate the best possible join and initialize the join structure

  RETURN VALUES
  0	ok
  1	Fatal error
*/
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1671

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1672 1673
static bool
make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
1674
		     DYNAMIC_ARRAY *keyuse_array)
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1675 1676
{
  int error;
1677 1678 1679
  uint i,table_count,const_count,key;
  table_map found_const_table_map, all_table_map, found_ref, refs;
  key_map const_ref, eq_part;
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  TABLE **table_vector;
  JOIN_TAB *stat,*stat_end,*s,**stat_ref;
  KEYUSE *keyuse,*start_keyuse;
  table_map outer_join=0;
  JOIN_TAB *stat_vector[MAX_TABLES+1];
  DBUG_ENTER("make_join_statistics");

  table_count=join->tables;
1688 1689
  stat=(JOIN_TAB*) join->thd->calloc(sizeof(JOIN_TAB)*table_count);
  stat_ref=(JOIN_TAB**) join->thd->alloc(sizeof(JOIN_TAB*)*MAX_TABLES);
1690
  table_vector=(TABLE**) join->thd->alloc(sizeof(TABLE*)*(table_count*2));
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1691 1692 1693 1694 1695 1696
  if (!stat || !stat_ref || !table_vector)
    DBUG_RETURN(1);				// Eom /* purecov: inspected */

  join->best_ref=stat_vector;

  stat_end=stat+table_count;
1697
  found_const_table_map= all_table_map=0;
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1698 1699 1700 1701 1702 1703
  const_count=0;

  for (s=stat,i=0 ; tables ; s++,tables=tables->next,i++)
  {
    TABLE *table;
    stat_vector[i]=s;
1704 1705 1706 1707
    s->keys.init();
    s->const_keys.init();
    s->checked_keys.init();
    s->needed_reg.init();
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1708 1709
    table_vector[i]=s->table=table=tables->table;
    table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);// record count
1710
    table->quick_keys.clear_all();
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    table->reginfo.join_tab=s;
    table->reginfo.not_exists_optimize=0;
    bzero((char*) table->const_key_parts, sizeof(key_part_map)*table->keys);
    all_table_map|= table->map;
1715
    s->join=join;
1716
    s->info=0;					// For describe
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1717 1718
    if ((s->on_expr=tables->on_expr))
    {
1719
      /* Left join */
1720 1721
      if (!table->file->records)
      {						// Empty table
1722
	s->key_dependent=s->dependent=0;	// Ignore LEFT JOIN depend.
1723 1724 1725
	set_position(join,const_count++,s,(KEYUSE*) 0);
	continue;
      }
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1726 1727
      s->key_dependent=s->dependent=
	s->on_expr->used_tables() & ~(table->map);
1728 1729 1730 1731
      if (table->outer_join & JOIN_TYPE_LEFT)
	s->dependent|=stat_vector[i-1]->dependent | table_vector[i-1]->map;
      if (tables->outer_join & JOIN_TYPE_RIGHT)
	s->dependent|=tables->next->table->map;
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1732 1733 1734 1735 1736 1737 1738 1739
      outer_join|=table->map;
      continue;
    }
    if (tables->straight)			// We don't have to move this
      s->dependent= table_vector[i-1]->map | stat_vector[i-1]->dependent;
    else
      s->dependent=(table_map) 0;
    s->key_dependent=(table_map) 0;
1740
    if ((table->system || table->file->records <= 1) && ! s->dependent &&
1741
	!(table->file->table_flags() & HA_NOT_EXACT_COUNT) &&
1742
        !table->fulltext_searched)
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1743 1744 1745 1746 1747
    {
      set_position(join,const_count++,s,(KEYUSE*) 0);
    }
  }
  stat_vector[i]=0;
1748
  join->outer_join=outer_join;
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1749 1750

  /*
1751 1752 1753 1754
    If outer join: Re-arrange tables in stat_vector so that outer join
    tables are after all tables it is dependent of.
    For example: SELECT * from A LEFT JOIN B ON B.c=C.c, C WHERE A.C=C.C
    Will shift table B after table C.
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  */
  if (outer_join)
  {
    table_map used_tables=0L;
    for (i=0 ; i < join->tables-1 ; i++)
    {
      if (stat_vector[i]->dependent & ~used_tables)
      {
	JOIN_TAB *save= stat_vector[i];
	uint j;
	for (j=i+1;
	     j < join->tables && stat_vector[j]->dependent & ~used_tables;
	     j++)
	{
	  JOIN_TAB *tmp=stat_vector[j];		// Move element up
	  stat_vector[j]=save;
	  save=tmp;
	}
	if (j == join->tables)
	{
	  join->tables=0;			// Don't use join->table
	  my_error(ER_WRONG_OUTER_JOIN,MYF(0));
	  DBUG_RETURN(1);
	}
	stat_vector[i]=stat_vector[j];
	stat_vector[j]=save;
      }
      used_tables|= stat_vector[i]->table->map;
    }
  }

  if (conds || outer_join)
1787 1788
    if (update_ref_and_keys(join->thd, keyuse_array, stat, join->tables,
                            conds, ~outer_join, join->select_lex))
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1789 1790
      DBUG_RETURN(1);

1791
  /* Read tables with 0 or 1 rows (system tables) */
1792
  join->const_table_map= 0;
1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810

  for (POSITION *p_pos=join->positions, *p_end=p_pos+const_count;
       p_pos < p_end ;
       p_pos++)
  {
    int tmp;
    s= p_pos->table;
    s->type=JT_SYSTEM;
    join->const_table_map|=s->table->map;
    if ((tmp=join_read_const_table(s, p_pos)))
    {
      if (tmp > 0)
	DBUG_RETURN(1);			// Fatal error
    }
    else
      found_const_table_map|= s->table->map;
  }

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1811
  /* loop until no more const tables are found */
1812
  int ref_changed;
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1813 1814
  do
  {
1815
    ref_changed = 0;
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1816
    found_ref=0;
1817 1818 1819 1820 1821 1822 1823

    /*
      We only have to loop from stat_vector + const_count as
      set_position() will move all const_tables first in stat_vector
    */

    for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++)
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1824
    {
1825
      TABLE *table=s->table;
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1826 1827
      if (s->dependent)				// If dependent on some table
      {
1828
	// All dep. must be constants
1829
	if (s->dependent & ~(found_const_table_map))
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1830
	  continue;
1831
	if (table->file->records <= 1L &&
1832
	    !(table->file->table_flags() & HA_NOT_EXACT_COUNT))
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1833
	{					// system table
1834
	  int tmp= 0;
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1835
	  s->type=JT_SYSTEM;
1836
	  join->const_table_map|=table->map;
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1837
	  set_position(join,const_count++,s,(KEYUSE*) 0);
1838
	  if ((tmp= join_read_const_table(s,join->positions+const_count-1)))
1839 1840 1841 1842 1843 1844
	  {
	    if (tmp > 0)
	      DBUG_RETURN(1);			// Fatal error
	  }
	  else
	    found_const_table_map|= table->map;
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	  continue;
	}
      }
      /* check if table can be read by key or table only uses const refs */
      if ((keyuse=s->keyuse))
      {
	s->type= JT_REF;
	while (keyuse->table == table)
	{
	  start_keyuse=keyuse;
	  key=keyuse->key;
1856
	  s->keys.set_bit(key);               // QQ: remove this ?
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1858 1859 1860
	  refs=0;
          const_ref.clear_all();
	  eq_part.clear_all();
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1861 1862
	  do
	  {
1863
	    if (keyuse->val->type() != Item::NULL_ITEM && !keyuse->optimize)
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1864
	    {
1865
	      if (!((~found_const_table_map) & keyuse->used_tables))
1866
		const_ref.set_bit(keyuse->keypart);
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1867 1868
	      else
		refs|=keyuse->used_tables;
1869
	      eq_part.set_bit(keyuse->keypart);
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	    }
	    keyuse++;
	  } while (keyuse->table == table && keyuse->key == key);

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	  if (eq_part.is_prefix(table->key_info[key].key_parts) &&
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	      ((table->key_info[key].flags & (HA_NOSAME | HA_END_SPACE_KEY)) ==
	       HA_NOSAME) &&
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              !table->fulltext_searched)
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	  {
	    if (const_ref == eq_part)
	    {					// Found everything for ref.
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	      int tmp;
	      ref_changed = 1;
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	      s->type= JT_CONST;
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	      join->const_table_map|=table->map;
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	      set_position(join,const_count++,s,start_keyuse);
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	      if (create_ref_for_key(join, s, start_keyuse,
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				     found_const_table_map))
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		DBUG_RETURN(1);
	      if ((tmp=join_read_const_table(s,
					     join->positions+const_count-1)))
	      {
		if (tmp > 0)
		  DBUG_RETURN(1);			// Fatal error
	      }
	      else
		found_const_table_map|= table->map;
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	      break;
	    }
	    else
	      found_ref|= refs;		// Table is const if all refs are const
	  }
	}
      }
    }
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  } while (join->const_table_map & found_ref && ref_changed);
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  /* Calc how many (possible) matched records in each table */

  for (s=stat ; s < stat_end ; s++)
  {
    if (s->type == JT_SYSTEM || s->type == JT_CONST)
    {
      /* Only one matching row */
      s->found_records=s->records=s->read_time=1; s->worst_seeks=1.0;
      continue;
    }
    /* Approximate found rows and time to read them */
    s->found_records=s->records=s->table->file->records;
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    s->read_time=(ha_rows) s->table->file->scan_time();
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    /*
      Set a max range of how many seeks we can expect when using keys
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      This is can't be to high as otherwise we are likely to use
      table scan.
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    */
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    s->worst_seeks= min((double) s->found_records / 10,
			(double) s->read_time*3);
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    if (s->worst_seeks < 2.0)			// Fix for small tables
      s->worst_seeks=2.0;

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    if (! s->const_keys.is_clear_all())
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    {
      ha_rows records;
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      SQL_SELECT *select;
      select= make_select(s->table, found_const_table_map,
			  found_const_table_map,
			  s->on_expr ? s->on_expr : conds,
			  &error);
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      records= get_quick_record_count(join->thd, select, s->table,
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				      &s->const_keys, join->row_limit);
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      s->quick=select->quick;
      s->needed_reg=select->needed_reg;
      select->quick=0;
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      if (records == 0 && s->table->reginfo.impossible_range)
      {
	/*
	  Impossible WHERE or ON expression
	  In case of ON, we mark that the we match one empty NULL row.
	  In case of WHERE, don't set found_const_table_map to get the
	  caller to abort with a zero row result.
	*/
	join->const_table_map|= s->table->map;
	set_position(join,const_count++,s,(KEYUSE*) 0);
	s->type= JT_CONST;
	if (s->on_expr)
	{
	  /* Generate empty row */
	  s->info= "Impossible ON condition";
	  found_const_table_map|= s->table->map;
	  s->type= JT_CONST;
	  mark_as_null_row(s->table);		// All fields are NULL
	}
      }
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      if (records != HA_POS_ERROR)
      {
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	s->found_records=records;
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	s->read_time= (ha_rows) (s->quick ? s->quick->read_time : 0.0);
      }
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      delete select;
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    }
  }

  /* Find best combination and return it */
  join->join_tab=stat;
  join->map2table=stat_ref;
  join->table= join->all_tables=table_vector;
  join->const_tables=const_count;
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  join->found_const_table_map=found_const_table_map;
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  if (join->const_tables != join->tables)
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  {
    optimize_keyuse(join, keyuse_array);
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    find_best_combination(join,all_table_map & ~join->const_table_map);
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  }
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  else
  {
    memcpy((gptr) join->best_positions,(gptr) join->positions,
	   sizeof(POSITION)*join->const_tables);
    join->best_read=1.0;
  }
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  DBUG_RETURN(join->thd->killed || get_best_combination(join));
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}


/*****************************************************************************
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  Check with keys are used and with tables references with tables
  Updates in stat:
	  keys	     Bitmap of all used keys
	  const_keys Bitmap of all keys with may be used with quick_select
	  keyuse     Pointer to possible keys
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*****************************************************************************/

typedef struct key_field_t {		// Used when finding key fields
  Field		*field;
  Item		*val;			// May be empty if diff constant
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  uint		level;
  uint		optimize;
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  bool		eq_func;
} KEY_FIELD;

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/* Values in optimize */
#define KEY_OPTIMIZE_EXISTS		1
#define KEY_OPTIMIZE_REF_OR_NULL	2

/*
  Merge new key definitions to old ones, remove those not used in both

  This is called for OR between different levels
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  To be able to do 'ref_or_null' we merge a comparison of a column
  and 'column IS NULL' to one test.  This is useful for sub select queries
  that are internally transformed to something like:

  SELECT * FROM t1 WHERE t1.key=outer_ref_field or t1.key IS NULL 
*/
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static KEY_FIELD *
merge_key_fields(KEY_FIELD *start,KEY_FIELD *new_fields,KEY_FIELD *end,
		 uint and_level)
{
  if (start == new_fields)
    return start;				// Impossible or
  if (new_fields == end)
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    return start;				// No new fields, skip all
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  KEY_FIELD *first_free=new_fields;

  /* Mark all found fields in old array */
  for (; new_fields != end ; new_fields++)
  {
    for (KEY_FIELD *old=start ; old != first_free ; old++)
    {
      if (old->field == new_fields->field)
      {
	if (new_fields->val->used_tables())
	{
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	  /*
	    If the value matches, we can use the key reference.
	    If not, we keep it until we have examined all new values
	  */
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	  if (old->val->eq(new_fields->val, old->field->binary()))
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	  {
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	    old->level= and_level;
	    old->optimize= ((old->optimize & new_fields->optimize &
			     KEY_OPTIMIZE_EXISTS) |
			    ((old->optimize | new_fields->optimize) &
			     KEY_OPTIMIZE_REF_OR_NULL));
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	  }
	}
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	else if (old->eq_func && new_fields->eq_func &&
		 old->val->eq(new_fields->val, old->field->binary()))
		 
	{
	  old->level= and_level;
	  old->optimize= ((old->optimize & new_fields->optimize &
			   KEY_OPTIMIZE_EXISTS) |
			  ((old->optimize | new_fields->optimize) &
			   KEY_OPTIMIZE_REF_OR_NULL));
	}
	else if (old->eq_func && new_fields->eq_func &&
		 (old->val->is_null() || new_fields->val->is_null()))
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	{
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	  /* field = expression OR field IS NULL */
	  old->level= and_level;
	  old->optimize= KEY_OPTIMIZE_REF_OR_NULL;
	  /* Remember the NOT NULL value */
	  if (old->val->is_null())
	    old->val= new_fields->val;
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	}
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	else
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	{
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	  /*
	    We are comparing two different const.  In this case we can't
	    use a key-lookup on this so it's better to remove the value
	    and let the range optimzier handle it
	  */
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	  if (old == --first_free)		// If last item
	    break;
	  *old= *first_free;			// Remove old value
	  old--;				// Retry this value
	}
      }
    }
  }
  /* Remove all not used items */
  for (KEY_FIELD *old=start ; old != first_free ;)
  {
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    if (old->level != and_level)
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    {						// Not used in all levels
      if (old == --first_free)
	break;
      *old= *first_free;			// Remove old value
      continue;
    }
    old++;
  }
  return first_free;
}


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/*
  Add a possible key to array of possible keys if it's usable as a key

  SYNPOSIS
    add_key_field()
    key_fields			Pointer to add key, if usable
    and_level			And level, to be stored in KEY_FIELD
    field			Field used in comparision
    eq_func			True if we used =, <=> or IS NULL
    value			Value used for comparison with field
				Is NULL for BETWEEN and IN    
    usable_tables		Tables which can be used for key optimization

  NOTES
    If we are doing a NOT NULL comparison on a NOT NULL field in a outer join
    table, we store this to be able to do not exists optimization later.

  RETURN
    *key_fields is incremented if we stored a key in the array
*/

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static void
add_key_field(KEY_FIELD **key_fields,uint and_level,
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	      Field *field,bool eq_func,Item **value, uint num_values,
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	      table_map usable_tables)
{
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  uint exists_optimize= 0;
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  if (!(field->flags & PART_KEY_FLAG))
  {
    // Don't remove column IS NULL on a LEFT JOIN table
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    if (!eq_func || (*value)->type() != Item::NULL_ITEM ||
        !field->table->maybe_null || field->null_ptr)
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      return;					// Not a key. Skip it
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    exists_optimize= KEY_OPTIMIZE_EXISTS;
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  }
  else
  {
    table_map used_tables=0;
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    bool optimizable=0;
    for (uint i=0; i<num_values; i++)
    {
      used_tables|=(*value)->used_tables();
      if (!((*value)->used_tables() & (field->table->map | RAND_TABLE_BIT)))
        optimizable=1;
    }
    if (!optimizable)
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      return;
    if (!(usable_tables & field->table->map))
    {
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      if (!eq_func || (*value)->type() != Item::NULL_ITEM ||
          !field->table->maybe_null || field->null_ptr)
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	return;					// Can't use left join optimize
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      exists_optimize= KEY_OPTIMIZE_EXISTS;
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    }
    else
    {
      JOIN_TAB *stat=field->table->reginfo.join_tab;
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      key_map possible_keys=field->key_start;
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      possible_keys.intersect(field->table->keys_in_use_for_query);
      stat[0].keys.merge(possible_keys);             // Add possible keys
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      /*
	Save the following cases:
	Field op constant
	Field LIKE constant where constant doesn't start with a wildcard
	Field = field2 where field2 is in a different table
	Field op formula
	Field IS NULL
	Field IS NOT NULL
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         Field BETWEEN ...
         Field IN ...
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      */
      stat[0].key_dependent|=used_tables;

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      bool is_const=1;
      for (uint i=0; i<num_values; i++)
        is_const&= (*value)->const_item();
      if (is_const)
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        stat[0].const_keys.merge(possible_keys);
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      /*
	We can't always use indexes when comparing a string index to a
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	number. cmp_type() is checked to allow compare of dates to numbers.
        eq_func is NEVER true when num_values > 1
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       */
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      if (!eq_func ||
	  field->result_type() == STRING_RESULT &&
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	  (*value)->result_type() != STRING_RESULT &&
	  field->cmp_type() != (*value)->result_type())
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	return;
    }
  }
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  DBUG_ASSERT(num_values == 1);
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  /*
    For the moment eq_func is always true. This slot is reserved for future
    extensions where we want to remembers other things than just eq comparisons
  */
  DBUG_ASSERT(eq_func);
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  /* Store possible eq field */
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  (*key_fields)->field=		field;
  (*key_fields)->eq_func=	eq_func;
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  (*key_fields)->val=		*value;
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  (*key_fields)->level=		and_level;
  (*key_fields)->optimize=	exists_optimize;
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  (*key_fields)++;
}


static void
add_key_fields(JOIN_TAB *stat,KEY_FIELD **key_fields,uint *and_level,
	       COND *cond, table_map usable_tables)
{
  if (cond->type() == Item_func::COND_ITEM)
  {
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    KEY_FIELD *org_key_fields= *key_fields;

    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
      Item *item;
      while ((item=li++))
	add_key_fields(stat,key_fields,and_level,item,usable_tables);
      for (; org_key_fields != *key_fields ; org_key_fields++)
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	org_key_fields->level= *and_level;
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    }
    else
    {
      (*and_level)++;
      add_key_fields(stat,key_fields,and_level,li++,usable_tables);
      Item *item;
      while ((item=li++))
      {
	KEY_FIELD *start_key_fields= *key_fields;
	(*and_level)++;
	add_key_fields(stat,key_fields,and_level,item,usable_tables);
	*key_fields=merge_key_fields(org_key_fields,start_key_fields,
				     *key_fields,++(*and_level));
      }
    }
    return;
  }
  /* If item is of type 'field op field/constant' add it to key_fields */

  if (cond->type() != Item::FUNC_ITEM)
    return;
  Item_func *cond_func= (Item_func*) cond;
  switch (cond_func->select_optimize()) {
  case Item_func::OPTIMIZE_NONE:
    break;
  case Item_func::OPTIMIZE_KEY:
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    // BETWEEN or IN
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    if (cond_func->key_item()->real_item()->type() == Item::FIELD_ITEM &&
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	!(cond_func->used_tables() & OUTER_REF_TABLE_BIT))
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      add_key_field(key_fields,*and_level,
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		    ((Item_field*) (cond_func->key_item()->real_item()))->
		    field, 0,
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                    cond_func->arguments()+1, cond_func->argument_count()-1,
                    usable_tables);
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    break;
  case Item_func::OPTIMIZE_OP:
  {
    bool equal_func=(cond_func->functype() == Item_func::EQ_FUNC ||
		     cond_func->functype() == Item_func::EQUAL_FUNC);

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    if (cond_func->arguments()[0]->real_item()->type() == Item::FIELD_ITEM &&
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	!(cond_func->arguments()[0]->used_tables() & OUTER_REF_TABLE_BIT))
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    {
      add_key_field(key_fields,*and_level,
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		    ((Item_field*) (cond_func->arguments()[0])->real_item())
		    ->field,
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		    equal_func,
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                    cond_func->arguments()+1, 1, usable_tables);
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    }
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    if (cond_func->arguments()[1]->real_item()->type() == Item::FIELD_ITEM &&
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	cond_func->functype() != Item_func::LIKE_FUNC &&
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	!(cond_func->arguments()[1]->used_tables() & OUTER_REF_TABLE_BIT))
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    {
      add_key_field(key_fields,*and_level,
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		    ((Item_field*) (cond_func->arguments()[1])->real_item())
		    ->field,
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		    equal_func,
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		    cond_func->arguments(),1,usable_tables);
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    }
    break;
  }
  case Item_func::OPTIMIZE_NULL:
    /* column_name IS [NOT] NULL */
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    if (cond_func->arguments()[0]->real_item()->type() == Item::FIELD_ITEM &&
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	!(cond_func->used_tables() & OUTER_REF_TABLE_BIT))
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    {
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      Item *tmp=new Item_null;
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      if (!tmp)					// Should never be true
	return;
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      add_key_field(key_fields,*and_level,
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		    ((Item_field*) (cond_func->arguments()[0])->real_item())
		    ->field,
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		    cond_func->functype() == Item_func::ISNULL_FUNC,
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		    &tmp, 1, usable_tables);
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    }
    break;
  }
  return;
}

/*
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  Add all keys with uses 'field' for some keypart
  If field->and_level != and_level then only mark key_part as const_part
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*/

static uint
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max_part_bit(key_part_map bits)
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{
  uint found;
  for (found=0; bits & 1 ; found++,bits>>=1) ;
  return found;
}

static void
add_key_part(DYNAMIC_ARRAY *keyuse_array,KEY_FIELD *key_field)
{
  Field *field=key_field->field;
  TABLE *form= field->table;
  KEYUSE keyuse;

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  if (key_field->eq_func && !(key_field->optimize & KEY_OPTIMIZE_EXISTS))
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  {
    for (uint key=0 ; key < form->keys ; key++)
    {
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      if (!(form->keys_in_use_for_query.is_set(key)))
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	continue;
      if (form->key_info[key].flags & HA_FULLTEXT)
	continue;    // ToDo: ft-keys in non-ft queries.   SerG

      uint key_parts= (uint) form->key_info[key].key_parts;
      for (uint part=0 ; part <  key_parts ; part++)
      {
	if (field->eq(form->key_info[key].key_part[part].field))
	{
	  keyuse.table= field->table;
	  keyuse.val =  key_field->val;
	  keyuse.key =  key;
	  keyuse.keypart=part;
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	  keyuse.keypart_map= (key_part_map) 1 << part;
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	  keyuse.used_tables=key_field->val->used_tables();
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	  keyuse.optimize= key_field->optimize & KEY_OPTIMIZE_REF_OR_NULL;
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	  VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
	}
      }
    }
  }
}

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#define FT_KEYPART   (MAX_REF_PARTS+10)

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static void
add_ft_keys(DYNAMIC_ARRAY *keyuse_array,
            JOIN_TAB *stat,COND *cond,table_map usable_tables)
{
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  Item_func_match *cond_func=NULL;
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  if (!cond)
    return;

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  if (cond->type() == Item::FUNC_ITEM)
  {
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    Item_func *func=(Item_func *)cond;
    Item_func::Functype functype=  func->functype();
    if (functype == Item_func::FT_FUNC)
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      cond_func=(Item_func_match *)cond;
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    else if (func->arg_count == 2)
    {
      Item_func *arg0=(Item_func *)(func->arguments()[0]),
                *arg1=(Item_func *)(func->arguments()[1]);
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      if (arg1->const_item()  &&
          ((functype == Item_func::GE_FUNC && arg1->val()> 0) ||
           (functype == Item_func::GT_FUNC && arg1->val()>=0))  &&
           arg0->type() == Item::FUNC_ITEM            &&
           arg0->functype() == Item_func::FT_FUNC)
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        cond_func=(Item_func_match *) arg0;
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      else if (arg0->const_item() &&
               ((functype == Item_func::LE_FUNC && arg0->val()> 0) ||
                (functype == Item_func::LT_FUNC && arg0->val()>=0)) &&
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                arg1->type() == Item::FUNC_ITEM          &&
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                arg1->functype() == Item_func::FT_FUNC)
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        cond_func=(Item_func_match *) arg1;
    }
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  }
  else if (cond->type() == Item::COND_ITEM)
  {
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
      Item *item;
      while ((item=li++))
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        add_ft_keys(keyuse_array,stat,item,usable_tables);
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    }
  }

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  if (!cond_func || cond_func->key == NO_SUCH_KEY ||
      !(usable_tables & cond_func->table->map))
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    return;
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  KEYUSE keyuse;
  keyuse.table= cond_func->table;
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  keyuse.val =  cond_func;
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  keyuse.key =  cond_func->key;
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  keyuse.keypart= FT_KEYPART;
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  keyuse.used_tables=cond_func->key_item()->used_tables();
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  keyuse.optimize= 0;
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  keyuse.keypart_map= 0;
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  VOID(insert_dynamic(keyuse_array,(gptr) &keyuse));
}

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static int
sort_keyuse(KEYUSE *a,KEYUSE *b)
{
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  int res;
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  if (a->table->tablenr != b->table->tablenr)
    return (int) (a->table->tablenr - b->table->tablenr);
  if (a->key != b->key)
    return (int) (a->key - b->key);
  if (a->keypart != b->keypart)
    return (int) (a->keypart - b->keypart);
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  // Place const values before other ones
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  if ((res= test((a->used_tables & ~OUTER_REF_TABLE_BIT)) -
       test((b->used_tables & ~OUTER_REF_TABLE_BIT))))
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    return res;
  /* Place rows that are not 'OPTIMIZE_REF_OR_NULL' first */
  return (int) ((a->optimize & KEY_OPTIMIZE_REF_OR_NULL) -
		(b->optimize & KEY_OPTIMIZE_REF_OR_NULL));
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}


/*
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  Update keyuse array with all possible keys we can use to fetch rows
  join_tab is a array in tablenr_order
  stat is a reference array in 'prefered' order.
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*/

static bool
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update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
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		    uint tables, COND *cond, table_map normal_tables,
		    SELECT_LEX *select_lex)
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{
  uint	and_level,i,found_eq_constant;
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  KEY_FIELD *key_fields, *end, *field;
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  if (!(key_fields=(KEY_FIELD*)
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	thd->alloc(sizeof(key_fields[0])*
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		   (thd->lex->current_select->cond_count+1)*2)))
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    return TRUE; /* purecov: inspected */
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  and_level= 0;
  field= end= key_fields;
  if (my_init_dynamic_array(keyuse,sizeof(KEYUSE),20,64))
    return TRUE;
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  if (cond)
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  {
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    add_key_fields(join_tab,&end,&and_level,cond,normal_tables);
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    for (; field != end ; field++)
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    {
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      add_key_part(keyuse,field);
      /* Mark that we can optimize LEFT JOIN */
      if (field->val->type() == Item::NULL_ITEM &&
	  !field->field->real_maybe_null())
	field->field->table->reginfo.not_exists_optimize=1;
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    }
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  }
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  for (i=0 ; i < tables ; i++)
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  {
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    if (join_tab[i].on_expr)
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    {
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      add_key_fields(join_tab,&end,&and_level,join_tab[i].on_expr,
		     join_tab[i].table->map);
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    }
  }
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  /* fill keyuse with found key parts */
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  for ( ; field != end ; field++)
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    add_key_part(keyuse,field);
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  if (select_lex->ftfunc_list->elements)
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  {
    add_ft_keys(keyuse,join_tab,cond,normal_tables);
  }

  /*
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    Special treatment for ft-keys.
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    Remove the following things from KEYUSE:
    - ref if there is a keypart which is a ref and a const.
    - keyparts without previous keyparts.
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  */
  if (keyuse->elements)
  {
    KEYUSE end,*prev,*save_pos,*use;

    qsort(keyuse->buffer,keyuse->elements,sizeof(KEYUSE),
	  (qsort_cmp) sort_keyuse);

    bzero((char*) &end,sizeof(end));		/* Add for easy testing */
    VOID(insert_dynamic(keyuse,(gptr) &end));

    use=save_pos=dynamic_element(keyuse,0,KEYUSE*);
    prev=&end;
    found_eq_constant=0;
    for (i=0 ; i < keyuse->elements-1 ; i++,use++)
    {
      if (!use->used_tables)
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	use->table->const_key_parts[use->key]|= use->keypart_map;
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      if (use->keypart != FT_KEYPART)
      {
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	if (use->key == prev->key && use->table == prev->table)
	{
	  if (prev->keypart+1 < use->keypart ||
	      prev->keypart == use->keypart && found_eq_constant)
	    continue;				/* remove */
	}
	else if (use->keypart != 0)		// First found must be 0
	  continue;
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      }

      *save_pos= *use;
      prev=use;
      found_eq_constant= !use->used_tables;
      /* Save ptr to first use */
      if (!use->table->reginfo.join_tab->keyuse)
	use->table->reginfo.join_tab->keyuse=save_pos;
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      use->table->reginfo.join_tab->checked_keys.set_bit(use->key);
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      save_pos++;
    }
    i=(uint) (save_pos-(KEYUSE*) keyuse->buffer);
    VOID(set_dynamic(keyuse,(gptr) &end,i));
    keyuse->elements=i;
  }
  return FALSE;
}

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/*
  Update some values in keyuse for faster find_best_combination() loop
*/

static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array)
{
  KEYUSE *end,*keyuse= dynamic_element(keyuse_array, 0, KEYUSE*);

  for (end= keyuse+ keyuse_array->elements ; keyuse < end ; keyuse++)
  {
    table_map map;
    /*
      If we find a ref, assume this table matches a proportional
      part of this table.
      For example 100 records matching a table with 5000 records
      gives 5000/100 = 50 records per key
      Constant tables are ignored.
      To avoid bad matches, we don't make ref_table_rows less than 100.
    */
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    keyuse->ref_table_rows= ~(ha_rows) 0;	// If no ref
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    if (keyuse->used_tables &
	(map= (keyuse->used_tables & ~join->const_table_map &
	       ~OUTER_REF_TABLE_BIT)))
    {
      uint tablenr;
      for (tablenr=0 ; ! (map & 1) ; map>>=1, tablenr++) ;
      if (map == 1)			// Only one table
      {
	TABLE *tmp_table=join->all_tables[tablenr];
	keyuse->ref_table_rows= max(tmp_table->file->records, 100);
      }
    }
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    /*
      Outer reference (external field) is constant for single executing
      of subquery
    */
    if (keyuse->used_tables == OUTER_REF_TABLE_BIT)
      keyuse->ref_table_rows= 1;
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  }
}

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/*****************************************************************************
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  Go through all combinations of not marked tables and find the one
  which uses least records
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*****************************************************************************/

/* Save const tables first as used tables */

static void
set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key)
{
  join->positions[idx].table= table;
  join->positions[idx].key=key;
  join->positions[idx].records_read=1.0;	/* This is a const table */

  /* Move the const table as down as possible in best_ref */
  JOIN_TAB **pos=join->best_ref+idx+1;
  JOIN_TAB *next=join->best_ref[idx];
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  for (;next != table ; pos++)
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  {
    JOIN_TAB *tmp=pos[0];
    pos[0]=next;
    next=tmp;
  }
  join->best_ref[idx]=table;
}


static void
find_best_combination(JOIN *join, table_map rest_tables)
{
  DBUG_ENTER("find_best_combination");
  join->best_read=DBL_MAX;
  find_best(join,rest_tables, join->const_tables,1.0,0.0);
  DBUG_VOID_RETURN;
}


static void
find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
	  double read_time)
{
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  ha_rows rec;
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  double tmp;
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  THD *thd= join->thd;
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  if (!rest_tables)
  {
    DBUG_PRINT("best",("read_time: %g  record_count: %g",read_time,
		       record_count));

    read_time+=record_count/(double) TIME_FOR_COMPARE;
    if (join->sort_by_table &&
	join->sort_by_table != join->positions[join->const_tables].table->table)
      read_time+=record_count;			// We have to make a temp table
    if (read_time < join->best_read)
    {
      memcpy((gptr) join->best_positions,(gptr) join->positions,
	     sizeof(POSITION)*idx);
      join->best_read=read_time;
    }
    return;
  }
  if (read_time+record_count/(double) TIME_FOR_COMPARE >= join->best_read)
    return;					/* Found better before */

  JOIN_TAB *s;
  double best_record_count=DBL_MAX,best_read_time=DBL_MAX;
  for (JOIN_TAB **pos=join->best_ref+idx ; (s=*pos) ; pos++)
  {
    table_map real_table_bit=s->table->map;
    if ((rest_tables & real_table_bit) && !(rest_tables & s->dependent))
    {
      double best,best_time,records;
      best=best_time=records=DBL_MAX;
      KEYUSE *best_key=0;
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      uint best_max_key_part=0;
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      my_bool found_constraint= 0;
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      if (s->keyuse)
      {						/* Use key if possible */
	TABLE *table=s->table;
	KEYUSE *keyuse,*start_key=0;
	double best_records=DBL_MAX;
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	uint max_key_part=0;
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	/* Test how we can use keys */
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	rec= s->records/MATCHING_ROWS_IN_OTHER_TABLE;  // Assumed records/key
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	for (keyuse=s->keyuse ; keyuse->table == table ;)
	{
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	  key_part_map found_part=0;
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	  table_map found_ref=0;
	  uint key=keyuse->key;
	  KEY *keyinfo=table->key_info+key;
          bool ft_key=(keyuse->keypart == FT_KEYPART);
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	  uint found_ref_or_null= 0;
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	  /* Calculate how many key segments of the current key we can use */
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	  start_key=keyuse;
	  do
	  {
            uint keypart=keyuse->keypart;
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	    uint found_part_ref_or_null= KEY_OPTIMIZE_REF_OR_NULL;
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	    do
	    {
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	      if (!(rest_tables & keyuse->used_tables) &&
		  !(found_ref_or_null & keyuse->optimize))
	      {
		found_part|=keyuse->keypart_map;
		found_ref|= keyuse->used_tables;
		if (rec > keyuse->ref_table_rows)
		  rec= keyuse->ref_table_rows;
		found_part_ref_or_null&= keyuse->optimize;
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              }
	      keyuse++;
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	      found_ref_or_null|= found_part_ref_or_null;
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	    } while (keyuse->table == table && keyuse->key == key &&
		     keyuse->keypart == keypart);
	  } while (keyuse->table == table && keyuse->key == key);

	  /*
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	    Assume that that each key matches a proportional part of table.
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	  */
          if (!found_part && !ft_key)
	    continue;				// Nothing usable found
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	  if (rec < MATCHING_ROWS_IN_OTHER_TABLE)
	    rec= MATCHING_ROWS_IN_OTHER_TABLE;	// Fix for small tables
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          /*
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	    ft-keys require special treatment
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          */
          if (ft_key)
          {
            /*
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	      Really, there should be records=0.0 (yes!)
	      but 1.0 would be probably safer
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            */
            tmp=prev_record_reads(join,found_ref);
            records=1.0;
          }
          else
          {
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	  found_constraint= 1;
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	  /*
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	    Check if we found full key
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	  */
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	  if (found_part == PREV_BITS(uint,keyinfo->key_parts) &&
	      !found_ref_or_null)
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	  {				/* use eq key */
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	    max_key_part= (uint) ~0;
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	    if ((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY |
				   HA_END_SPACE_KEY)) == HA_NOSAME)
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	    {
	      tmp=prev_record_reads(join,found_ref);
	      records=1.0;
	    }
	    else
	    {
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	      if (!found_ref)
	      {					// We found a const key
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		if (table->quick_keys.is_set(key))
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		  records= (double) table->quick_rows[key];
		else
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		{
		  /* quick_range couldn't use key! */
		  records= (double) s->records/rec;
		}
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	      }
	      else
	      {
		if (!(records=keyinfo->rec_per_key[keyinfo->key_parts-1]))
		{				// Prefere longer keys
		  records=
		    ((double) s->records / (double) rec *
		     (1.0 +
		      ((double) (table->max_key_length-keyinfo->key_length) /
		       (double) table->max_key_length)));
		  if (records < 2.0)
		    records=2.0;		// Can't be as good as a unique
		}
	      }
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	      /* Limit the number of matched rows */
	      tmp= records;
	      set_if_smaller(tmp, (double) thd->variables.max_seeks_for_key);
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	      if (table->used_keys.is_set(key))
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	      {
		/* we can use only index tree */
		uint keys_per_block= table->file->block_size/2/
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		  (keyinfo->key_length+table->file->ref_length)+1;
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		tmp=record_count*(tmp+keys_per_block-1)/keys_per_block;
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	      }
	      else
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		tmp=record_count*min(tmp,s->worst_seeks);
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	    }
	  }
	  else
	  {
	    /*
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	      Use as much key-parts as possible and a uniq key is better
	      than a not unique key
	      Set tmp to (previous record count) * (records / combination)
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	    */
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	    if ((found_part & 1) &&
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		(!(table->file->index_flags(key) & HA_ONLY_WHOLE_INDEX) ||
		 found_part == PREV_BITS(uint,keyinfo->key_parts)))
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	    {
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	      max_key_part=max_part_bit(found_part);
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	      /*
		Check if quick_range could determinate how many rows we
		will match
	      */
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	      if (table->quick_keys.is_set(key) &&
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		  table->quick_key_parts[key] <= max_key_part)
		tmp=records= (double) table->quick_rows[key];
	      else
	      {
		/* Check if we have statistic about the distribution */
		if ((records=keyinfo->rec_per_key[max_key_part-1]))
		  tmp=records;
		else
		{
		  /*
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		    Assume that the first key part matches 1% of the file
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		    and that the hole key matches 10 (duplicates) or 1
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		    (unique) records.
		    Assume also that more key matches proportionally more
		    records
		    This gives the formula:
		    records= (x * (b-a) + a*c-b)/(c-1)
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		    b = records matched by whole key
		    a = records matched by first key part (10% of all records?)
		    c = number of key parts in key
		    x = used key parts (1 <= x <= c)
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		  */
		  double rec_per_key;
		  if (!(rec_per_key=(double)
			keyinfo->rec_per_key[keyinfo->key_parts-1]))
		    rec_per_key=(double) s->records/rec+1;

		  if (!s->records)
		    tmp=0;
		  else if (rec_per_key/(double) s->records >= 0.01)
		    tmp=rec_per_key;
		  else
		  {
		    double a=s->records*0.01;
		    tmp=(max_key_part * (rec_per_key - a) +
			 a*keyinfo->key_parts - rec_per_key)/
		      (keyinfo->key_parts-1);
		    set_if_bigger(tmp,1.0);
		  }
		  records=(ulong) tmp;
		}
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		if (found_ref_or_null)
		{
		  /* We need to do two key searches to find key */
		  tmp*= 2.0;
		  records*= 2.0;
		}
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	      }
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	      /* Limit the number of matched rows */
	      set_if_smaller(tmp, (double) thd->variables.max_seeks_for_key);
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	      if (table->used_keys.is_set(key))
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	      {
		/* we can use only index tree */
		uint keys_per_block= table->file->block_size/2/
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		  (keyinfo->key_length+table->file->ref_length)+1;
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		tmp=record_count*(tmp+keys_per_block-1)/keys_per_block;
	      }
	      else
		tmp=record_count*min(tmp,s->worst_seeks);
	    }
	    else
	      tmp=best_time;			// Do nothing
	  }
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          } /* not ft_key */
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	  if (tmp < best_time - records/(double) TIME_FOR_COMPARE)
	  {
	    best_time=tmp + records/(double) TIME_FOR_COMPARE;
	    best=tmp;
	    best_records=records;
	    best_key=start_key;
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	    best_max_key_part=max_key_part;
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	  }
	}
	records=best_records;
      }
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      /*
	Don't test table scan if it can't be better.
	Prefer key lookup if we would use the same key for scanning.
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	Don't do a table scan on InnoDB tables, if we can read the used
	parts of the row from any of the used index.
	This is because table scans uses index and we would not win
	anything by using a table scan.
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      */
      if ((records >= s->found_records || best > s->read_time) &&
	  !(s->quick && best_key && s->quick->index == best_key->key &&
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	    best_max_key_part >= s->table->quick_key_parts[best_key->key]) &&
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	  !((s->table->file->table_flags() & HA_TABLE_SCAN_ON_INDEX) &&
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	    ! s->table->used_keys.is_clear_all() && best_key) &&
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	  !(s->table->force_index && best_key))
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      {						// Check full join
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        ha_rows rnd_records= s->found_records;
        /*
          If there is a restriction on the table, assume that 25% of the
          rows can be skipped on next part.
          This is to force tables that this table depends on before this
          table
        */
        if (found_constraint)
          rnd_records-= rnd_records/4;

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        /*
          Range optimizer never proposes a RANGE if it isn't better
          than FULL: so if RANGE is present, it's always preferred to FULL.
          Here we estimate its cost.
        */
        if (s->quick)
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        {
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          /*
            For each record we:
             - read record range through 'quick'
             - skip rows which does not satisfy WHERE constraints
           */
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          tmp= record_count *
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               (s->quick->read_time +
               (s->found_records - rnd_records)/(double) TIME_FOR_COMPARE);
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        }
        else
        {
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          /* Estimate cost of reading table. */
          tmp= s->table->file->scan_time();
          if (s->on_expr)                         // Can't use join cache
          {
            /*
              For each record we have to:
              - read the whole table record 
              - skip rows which does not satisfy join condition
            */
            tmp= record_count *
                 (tmp +     
                 (s->records - rnd_records)/(double) TIME_FOR_COMPARE);
          }
          else
          {
            /* We read the table as many times as join buffer becomes full. */
            tmp*= (1.0 + floor((double) cache_record_length(join,idx) *
                               record_count /
                               (double) thd->variables.join_buff_size));
            /* 
              We don't make full cartesian product between rows in the scanned
              table and existing records because we skip all rows from the
              scanned table, which does not satisfy join condition when 
              we read the table (see flush_cached_records for details). Here we
              take into account cost to read and skip these records.
            */
            tmp+= (s->records - rnd_records)/(double) TIME_FOR_COMPARE;
          }
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        }
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        /*
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          We estimate the cost of evaluating WHERE clause for found records
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          as record_count * rnd_records / TIME_FOR_COMPARE. This cost plus
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          tmp give us total cost of using TABLE SCAN
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        */
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	if (best == DBL_MAX ||
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	    (tmp  + record_count/(double) TIME_FOR_COMPARE*rnd_records <
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	     best + record_count/(double) TIME_FOR_COMPARE*records))
	{
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	  /*
	    If the table has a range (s->quick is set) make_join_select()
	    will ensure that this will be used
	  */
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	  best=tmp;
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	  records= rows2double(rnd_records);
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	  best_key=0;
	}
      }
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      join->positions[idx].records_read= records;
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      join->positions[idx].key=best_key;
      join->positions[idx].table= s;
      if (!best_key && idx == join->const_tables &&
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	  s->table == join->sort_by_table &&
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	  join->unit->select_limit_cnt >= records)
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	join->sort_by_table= (TABLE*) 1;	// Must use temporary table

     /*
	Go to the next level only if there hasn't been a better key on
	this level! This will cut down the search for a lot simple cases!
       */
      double current_record_count=record_count*records;
      double current_read_time=read_time+best;
      if (best_record_count > current_record_count ||
	  best_read_time > current_read_time ||
	  idx == join->const_tables && s->table == join->sort_by_table)
      {
	if (best_record_count >= current_record_count &&
	    best_read_time >= current_read_time &&
	    (!(s->key_dependent & rest_tables) || records < 2.0))
	{
	  best_record_count=current_record_count;
	  best_read_time=current_read_time;
	}
	swap(JOIN_TAB*,join->best_ref[idx],*pos);
	find_best(join,rest_tables & ~real_table_bit,idx+1,
		  current_record_count,current_read_time);
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        if (thd->killed)
          return;
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	swap(JOIN_TAB*,join->best_ref[idx],*pos);
      }
      if (join->select_options & SELECT_STRAIGHT_JOIN)
	break;				// Don't test all combinations
    }
  }
}


/*
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  Find how much space the prevous read not const tables takes in cache
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*/

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static void calc_used_field_length(THD *thd, JOIN_TAB *join_tab)
{
  uint null_fields,blobs,fields,rec_length;
  null_fields=blobs=fields=rec_length=0;

  Field **f_ptr,*field;
  for (f_ptr=join_tab->table->field ; (field= *f_ptr) ; f_ptr++)
  {
    if (field->query_id == thd->query_id)
    {
      uint flags=field->flags;
      fields++;
      rec_length+=field->pack_length();
      if (flags & BLOB_FLAG)
	blobs++;
      if (!(flags & NOT_NULL_FLAG))
	null_fields++;
    }
  }
  if (null_fields)
    rec_length+=(join_tab->table->null_fields+7)/8;
  if (join_tab->table->maybe_null)
    rec_length+=sizeof(my_bool);
  if (blobs)
  {
    uint blob_length=(uint) (join_tab->table->file->mean_rec_length-
			     (join_tab->table->reclength- rec_length));
    rec_length+=(uint) max(4,blob_length);
  }
  join_tab->used_fields=fields;
  join_tab->used_fieldlength=rec_length;
  join_tab->used_blobs=blobs;
}


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static uint
cache_record_length(JOIN *join,uint idx)
{
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  uint length=0;
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  JOIN_TAB **pos,**end;
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  THD *thd=join->thd;
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  for (pos=join->best_ref+join->const_tables,end=join->best_ref+idx ;
       pos != end ;
       pos++)
  {
    JOIN_TAB *join_tab= *pos;
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    if (!join_tab->used_fieldlength)		/* Not calced yet */
      calc_used_field_length(thd, join_tab);
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    length+=join_tab->used_fieldlength;
  }
  return length;
}


static double
prev_record_reads(JOIN *join,table_map found_ref)
{
  double found=1.0;
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  found_ref&= ~OUTER_REF_TABLE_BIT;
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  for (POSITION *pos=join->positions ; found_ref ; pos++)
  {
    if (pos->table->table->map & found_ref)
    {
      found_ref&= ~pos->table->table->map;
      found*=pos->records_read;
    }
  }
  return found;
}


/*****************************************************************************
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  Set up join struct according to best position.
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*****************************************************************************/

static bool
get_best_combination(JOIN *join)
{
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  uint i,tablenr;
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  table_map used_tables;
  JOIN_TAB *join_tab,*j;
  KEYUSE *keyuse;
  uint table_count;
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  THD *thd=join->thd;
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  table_count=join->tables;
  if (!(join->join_tab=join_tab=
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	(JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB)*table_count)))
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    return TRUE;

  join->full_join=0;

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  used_tables= OUTER_REF_TABLE_BIT;		// Outer row is already read
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  for (j=join_tab, tablenr=0 ; tablenr < table_count ; tablenr++,j++)
  {
    TABLE *form;
    *j= *join->best_positions[tablenr].table;
    form=join->table[tablenr]=j->table;
    used_tables|= form->map;
    form->reginfo.join_tab=j;
    if (!j->on_expr)
      form->reginfo.not_exists_optimize=0;	// Only with LEFT JOIN
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    if (j->type == JT_CONST)
      continue;					// Handled in make_join_stat..

    j->ref.key = -1;
    j->ref.key_parts=0;
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    if (j->type == JT_SYSTEM)
      continue;
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    if (j->keys.is_clear_all() || !(keyuse= join->best_positions[tablenr].key))
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    {
      j->type=JT_ALL;
      if (tablenr != join->const_tables)
	join->full_join=1;
    }
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    else if (create_ref_for_key(join, j, keyuse, used_tables))
      return TRUE;				// Something went wrong
  }
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  for (i=0 ; i < table_count ; i++)
    join->map2table[join->join_tab[i].table->tablenr]=join->join_tab+i;
  update_depend_map(join);
  return 0;
}
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static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
			       table_map used_tables)
{
  KEYUSE *keyuse=org_keyuse;
  bool ftkey=(keyuse->keypart == FT_KEYPART);
  THD  *thd= join->thd;
  uint keyparts,length,key;
  TABLE *table;
  KEY *keyinfo;
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  /*  Use best key from find_best */
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  table=j->table;
  key=keyuse->key;
  keyinfo=table->key_info+key;

  if (ftkey)
  {
    Item_func_match *ifm=(Item_func_match *)keyuse->val;

    length=0;
    keyparts=1;
    ifm->join_key=1;
  }
  else
  {
    keyparts=length=0;
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    uint found_part_ref_or_null= 0;
    /*
      Calculate length for the used key
      Stop if there is a missing key part or when we find second key_part
      with KEY_OPTIMIZE_REF_OR_NULL
    */
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    do
    {
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      if (!(~used_tables & keyuse->used_tables))
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      {
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	if (keyparts == keyuse->keypart &&
	    !(found_part_ref_or_null & keyuse->optimize))
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	{
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	  keyparts++;
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	  length+= keyinfo->key_part[keyuse->keypart].store_length;
	  found_part_ref_or_null|= keyuse->optimize;
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	}
      }
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      keyuse++;
    } while (keyuse->table == table && keyuse->key == key);
  } /* not ftkey */

  /* set up fieldref */
  keyinfo=table->key_info+key;
  j->ref.key_parts=keyparts;
  j->ref.key_length=length;
  j->ref.key=(int) key;
  if (!(j->ref.key_buff= (byte*) thd->calloc(ALIGN_SIZE(length)*2)) ||
      !(j->ref.key_copy= (store_key**) thd->alloc((sizeof(store_key*) *
						   (keyparts+1)))) ||
      !(j->ref.items=    (Item**) thd->alloc(sizeof(Item*)*keyparts)))
  {
    return TRUE;
  }
  j->ref.key_buff2=j->ref.key_buff+ALIGN_SIZE(length);
  j->ref.key_err=1;
  keyuse=org_keyuse;

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  store_key **ref_key= j->ref.key_copy;
  byte *key_buff=j->ref.key_buff, *null_ref_key= 0;
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  if (ftkey)
  {
    j->ref.items[0]=((Item_func*)(keyuse->val))->key_item();
    if (keyuse->used_tables)
      return TRUE; // not supported yet. SerG

    j->type=JT_FT;
  }
  else
  {
    uint i;
    for (i=0 ; i < keyparts ; keyuse++,i++)
    {
      while (keyuse->keypart != i ||
	     ((~used_tables) & keyuse->used_tables))
	keyuse++;				/* Skip other parts */

      uint maybe_null= test(keyinfo->key_part[i].null_bit);
      j->ref.items[i]=keyuse->val;		// Save for cond removal
      if (!keyuse->used_tables &&
	  !(join->select_options & SELECT_DESCRIBE))
      {					// Compare against constant
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	store_key_item tmp(thd, keyinfo->key_part[i].field,
                           (char*)key_buff + maybe_null,
                           maybe_null ?  (char*) key_buff : 0,
                           keyinfo->key_part[i].length, keyuse->val);
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	if (thd->is_fatal_error)
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	  return TRUE;
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	tmp.copy();
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      }
      else
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	*ref_key++= get_store_key(thd,
				  keyuse,join->const_table_map,
				  &keyinfo->key_part[i],
				  (char*) key_buff,maybe_null);
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      /* Remmeber if we are going to use REF_OR_NULL */
      if (keyuse->optimize & KEY_OPTIMIZE_REF_OR_NULL)
	null_ref_key= key_buff;
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      key_buff+=keyinfo->key_part[i].store_length;
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    }
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  } /* not ftkey */
  *ref_key=0;				// end_marker
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  if (j->type == JT_FT)
    return 0;
  if (j->type == JT_CONST)
    j->table->const_table= 1;
3253
  else if (((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY |
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			       HA_END_SPACE_KEY)) != HA_NOSAME) ||
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	   keyparts != keyinfo->key_parts || null_ref_key)
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  {
    /* Must read with repeat */
    j->type= null_ref_key ? JT_REF_OR_NULL : JT_REF;
    j->null_ref_key= null_ref_key;
  }
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  else if (ref_key == j->ref.key_copy)
3262
  {
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    /*
      This happen if we are using a constant expression in the ON part
      of an LEFT JOIN.
      SELECT * FROM a LEFT JOIN b ON b.key=30
      Here we should not mark the table as a 'const' as a field may
      have a 'normal' value or a NULL value.
    */
    j->type=JT_CONST;
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  }
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  else
    j->type=JT_EQ_REF;
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  return 0;
}


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static store_key *
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get_store_key(THD *thd, KEYUSE *keyuse, table_map used_tables,
	      KEY_PART_INFO *key_part, char *key_buff, uint maybe_null)
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{
  if (!((~used_tables) & keyuse->used_tables))		// if const item
  {
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    return new store_key_const_item(thd,
				    key_part->field,
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				    key_buff + maybe_null,
				    maybe_null ? key_buff : 0,
				    key_part->length,
				    keyuse->val);
  }
  else if (keyuse->val->type() == Item::FIELD_ITEM)
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    return new store_key_field(thd,
			       key_part->field,
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			       key_buff + maybe_null,
			       maybe_null ? key_buff : 0,
			       key_part->length,
			       ((Item_field*) keyuse->val)->field,
			       keyuse->val->full_name());
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  return new store_key_item(thd,
			    key_part->field,
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			    key_buff + maybe_null,
			    maybe_null ? key_buff : 0,
			    key_part->length,
			    keyuse->val);
}

/*
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  This function is only called for const items on fields which are keys
  returns 1 if there was some conversion made when the field was stored.
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*/

bool
store_val_in_field(Field *field,Item *item)
{
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  bool error;
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  THD *thd=current_thd;
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  ha_rows cuted_fields=thd->cuted_fields;
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  thd->count_cuted_fields= CHECK_FIELD_WARN;
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  error= item->save_in_field(field, 1);
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  thd->count_cuted_fields= CHECK_FIELD_IGNORE;
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  return error || cuted_fields != thd->cuted_fields;
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}


static bool
make_simple_join(JOIN *join,TABLE *tmp_table)
{
  TABLE **tableptr;
  JOIN_TAB *join_tab;

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  if (!(tableptr=(TABLE**) join->thd->alloc(sizeof(TABLE*))) ||
      !(join_tab=(JOIN_TAB*) join->thd->alloc(sizeof(JOIN_TAB))))
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    return TRUE;
  join->join_tab=join_tab;
  join->table=tableptr; tableptr[0]=tmp_table;
  join->tables=1;
  join->const_tables=0;
  join->const_table_map=0;
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  join->tmp_table_param.field_count= join->tmp_table_param.sum_func_count=
    join->tmp_table_param.func_count=0;
  join->tmp_table_param.copy_field=join->tmp_table_param.copy_field_end=0;
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  join->first_record=join->sort_and_group=0;
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  join->send_records=(ha_rows) 0;
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  join->group=0;
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  join->row_limit=join->unit->select_limit_cnt;
3347
  join->do_send_rows = (join->row_limit) ? 1 : 0;
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  join_tab->cache.buff=0;			/* No caching */
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  join_tab->table=tmp_table;
  join_tab->select=0;
  join_tab->select_cond=0;
  join_tab->quick=0;
  join_tab->type= JT_ALL;			/* Map through all records */
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  join_tab->keys.init(~0);                      /* test everything in quick */
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  join_tab->info=0;
  join_tab->on_expr=0;
  join_tab->ref.key = -1;
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  join_tab->not_used_in_distinct=0;
  join_tab->read_first_record= join_init_read_record;
3361
  join_tab->join=join;
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  bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record));
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  tmp_table->status=0;
  tmp_table->null_row=0;
  return FALSE;
}


static bool
make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
{
  DBUG_ENTER("make_join_select");
  if (select)
  {
    table_map used_tables;
    if (join->tables > 1)
      cond->update_used_tables();		// Tablenr may have changed
3378 3379
    if (join->const_tables == join->tables)
      join->const_table_map|=RAND_TABLE_BIT;
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    {						// Check const tables
      COND *const_cond=
	make_cond_for_table(cond,join->const_table_map,(table_map) 0);
      DBUG_EXECUTE("where",print_where(const_cond,"constants"););
      if (const_cond && !const_cond->val_int())
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      {
	DBUG_PRINT("info",("Found impossible WHERE condition"));
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	DBUG_RETURN(1);				// Impossible const condition
3388
      }
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    }
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    used_tables=((select->const_tables=join->const_table_map) |
		 OUTER_REF_TABLE_BIT | RAND_TABLE_BIT);
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    for (uint i=join->const_tables ; i < join->tables ; i++)
    {
      JOIN_TAB *tab=join->join_tab+i;
      table_map current_map= tab->table->map;
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      /*
	Following force including random expression in last table condition.
	It solve problem with select like SELECT * FROM t1 WHERE rand() > 0.5
      */
3400
      if (i == join->tables-1)
3401
	current_map|= OUTER_REF_TABLE_BIT | RAND_TABLE_BIT;
3402
      bool use_quick_range=0;
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      used_tables|=current_map;
3404 3405

      if (tab->type == JT_REF && tab->quick &&
3406
	  (uint) tab->ref.key == tab->quick->index &&
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	  tab->ref.key_length < tab->quick->max_used_key_length)
      {
	/* Range uses longer key;  Use this instead of ref on key */
	tab->type=JT_ALL;
	use_quick_range=1;
	tab->use_quick=1;
	tab->ref.key_parts=0;		// Don't use ref key.
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	join->best_positions[i].records_read= rows2double(tab->quick->records);
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      }

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      COND *tmp=make_cond_for_table(cond,used_tables,current_map);
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      if (!tmp && tab->quick)
      {						// Outer join
	/*
	  Hack to handle the case where we only refer to a table
	  in the ON part of an OUTER JOIN.
	*/
	tmp=new Item_int((longlong) 1,1);	// Always true
      }
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      if (tmp)
      {
	DBUG_EXECUTE("where",print_where(tmp,tab->table->table_name););
	SQL_SELECT *sel=tab->select=(SQL_SELECT*)
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	  join->thd->memdup((gptr) select, sizeof(SQL_SELECT));
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	if (!sel)
	  DBUG_RETURN(1);			// End of memory
	tab->select_cond=sel->cond=tmp;
	sel->head=tab->table;
	if (tab->quick)
	{
3437 3438
	  /* Use quick key read if it's a constant and it's not used
	     with key reading */
3439
	  if (tab->needed_reg.is_clear_all() && tab->type != JT_EQ_REF
3440
	      && tab->type != JT_FT && (tab->type != JT_REF ||
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	       (uint) tab->ref.key == tab->quick->index))
	  {
	    sel->quick=tab->quick;		// Use value from get_quick_...
3444 3445
	    sel->quick_keys.clear_all();
	    sel->needed_reg.clear_all();
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	  }
	  else
	  {
	    delete tab->quick;
	  }
	  tab->quick=0;
	}
	uint ref_key=(uint) sel->head->reginfo.join_tab->ref.key+1;
	if (i == join->const_tables && ref_key)
	{
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	  if (!tab->const_keys.is_clear_all() &&
              tab->table->reginfo.impossible_range)
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	    DBUG_RETURN(1);
	}
3460
	else if (tab->type == JT_ALL && ! use_quick_range)
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	{
3462
	  if (!tab->const_keys.is_clear_all() &&
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	      tab->table->reginfo.impossible_range)
	    DBUG_RETURN(1);				// Impossible range
	  /*
	    We plan to scan all rows.
3467 3468 3469
	    Check again if we should use an index.
	    We could have used an column from a previous table in
	    the index if we are using limit and this is the first table
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	  */

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	  if ((!tab->keys.is_subset(tab->const_keys) && i > 0) ||
	      (!tab->const_keys.is_clear_all() && i == join->const_tables &&
	       join->unit->select_limit_cnt <
3475
	       join->best_positions[i].records_read &&
3476
	       !(join->select_options & OPTION_FOUND_ROWS)))
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	  {
3478 3479 3480
	    /* Join with outer join condition */
	    COND *orig_cond=sel->cond;
	    sel->cond=and_conds(sel->cond,tab->on_expr);
3481
	    if (sel->test_quick_select(join->thd, tab->keys,
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				       used_tables & ~ current_map,
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				       (join->select_options &
					OPTION_FOUND_ROWS ?
					HA_POS_ERROR :
3486
					join->unit->select_limit_cnt)) < 0)
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            {
	      /*
		Before reporting "Impossible WHERE" for the whole query
		we have to check isn't it only "impossible ON" instead
	      */
3492 3493
              sel->cond=orig_cond;
              if (!tab->on_expr ||
3494
                  sel->test_quick_select(join->thd, tab->keys,
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                                         used_tables & ~ current_map,
                                         (join->select_options &
                                          OPTION_FOUND_ROWS ?
                                          HA_POS_ERROR :
3499 3500
                                          join->unit->select_limit_cnt)) < 0)
		DBUG_RETURN(1);			// Impossible WHERE
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            }
            else
	      sel->cond=orig_cond;

3505 3506 3507
	    /* Fix for EXPLAIN */
	    if (sel->quick)
	      join->best_positions[i].records_read= sel->quick->records;
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	  }
	  else
	  {
	    sel->needed_reg=tab->needed_reg;
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	    sel->quick_keys.clear_all();
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	  }
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	  if (!sel->quick_keys.is_subset(tab->checked_keys) ||
              !sel->needed_reg.is_subset(tab->checked_keys))
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	  {
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	    tab->keys=sel->quick_keys;
            tab->keys.merge(sel->needed_reg);
	    tab->use_quick= (!sel->needed_reg.is_clear_all() &&
			     (select->quick_keys.is_clear_all() ||
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			      (select->quick &&
			       (select->quick->records >= 100L)))) ?
	      2 : 1;
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	    sel->read_tables= used_tables & ~current_map;
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	  }
	  if (i != join->const_tables && tab->use_quick != 2)
	  {					/* Read with cache */
	    if ((tmp=make_cond_for_table(cond,
					 join->const_table_map |
					 current_map,
					 current_map)))
	    {
	      DBUG_EXECUTE("where",print_where(tmp,"cache"););
3534 3535
	      tab->cache.select=(SQL_SELECT*)
		join->thd->memdup((gptr) sel, sizeof(SQL_SELECT));
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	      tab->cache.select->cond=tmp;
	      tab->cache.select->read_tables=join->const_table_map;
	    }
	  }
	}
      }
    }
  }
  DBUG_RETURN(0);
}


static void
3549
make_join_readinfo(JOIN *join, uint options)
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{
  uint i;
3552
  SELECT_LEX *select_lex= &join->thd->lex->select_lex;
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  DBUG_ENTER("make_join_readinfo");

  for (i=join->const_tables ; i < join->tables ; i++)
  {
    JOIN_TAB *tab=join->join_tab+i;
    TABLE *table=tab->table;
    tab->read_record.table= table;
    tab->read_record.file=table->file;
    tab->next_select=sub_select;		/* normal select */
    switch (tab->type) {
    case JT_SYSTEM:				// Only happens with left join
      table->status=STATUS_NO_RECORD;
      tab->read_first_record= join_read_system;
      tab->read_record.read_record= join_no_more_records;
      break;
    case JT_CONST:				// Only happens with left join
      table->status=STATUS_NO_RECORD;
      tab->read_first_record= join_read_const;
      tab->read_record.read_record= join_no_more_records;
      break;
    case JT_EQ_REF:
      table->status=STATUS_NO_RECORD;
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      if (tab->select)
      {
	delete tab->select->quick;
	tab->select->quick=0;
      }
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      delete tab->quick;
      tab->quick=0;
      table->file->index_init(tab->ref.key);
      tab->read_first_record= join_read_key;
      tab->read_record.read_record= join_no_more_records;
3585
      if (table->used_keys.is_set(tab->ref.key) &&
3586
	  !table->no_keyread)
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      {
	table->key_read=1;
	table->file->extra(HA_EXTRA_KEYREAD);
      }
      break;
3592
    case JT_REF_OR_NULL:
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    case JT_REF:
      table->status=STATUS_NO_RECORD;
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      if (tab->select)
      {
	delete tab->select->quick;
	tab->select->quick=0;
      }
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      delete tab->quick;
      tab->quick=0;
      table->file->index_init(tab->ref.key);
3603
      if (table->used_keys.is_set(tab->ref.key) &&
3604
	  !table->no_keyread)
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      {
	table->key_read=1;
	table->file->extra(HA_EXTRA_KEYREAD);
      }
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      if (tab->type == JT_REF)
      {
	tab->read_first_record= join_read_always_key;
	tab->read_record.read_record= join_read_next_same;
      }
      else
      {
	tab->read_first_record= join_read_always_key_or_null;
	tab->read_record.read_record= join_read_next_same_or_null;
      }
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      break;
    case JT_FT:
      table->status=STATUS_NO_RECORD;
      table->file->index_init(tab->ref.key);
      tab->read_first_record= join_ft_read_first;
      tab->read_record.read_record= join_ft_read_next;
      break;
    case JT_ALL:
      /*
3628
	If previous table use cache
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      */
      table->status=STATUS_NO_RECORD;
3631
      if (i != join->const_tables && !(options & SELECT_NO_JOIN_CACHE) &&
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	  tab->use_quick != 2 && !tab->on_expr)
      {
	if ((options & SELECT_DESCRIBE) ||
	    !join_init_cache(join->thd,join->join_tab+join->const_tables,
			     i-join->const_tables))
	{
	  tab[-1].next_select=sub_select_cache; /* Patch previous */
	}
      }
      /* These init changes read_record */
      if (tab->use_quick == 2)
3643
      {
3644
	join->thd->server_status|=SERVER_QUERY_NO_GOOD_INDEX_USED;
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	tab->read_first_record= join_init_quick_read_record;
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	statistic_increment(select_range_check_count, &LOCK_status);
      }
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      else
      {
	tab->read_first_record= join_init_read_record;
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	if (i == join->const_tables)
	{
	  if (tab->select && tab->select->quick)
	  {
	    statistic_increment(select_range_count, &LOCK_status);
	  }
	  else
	  {
3659
	    join->thd->server_status|=SERVER_QUERY_NO_INDEX_USED;
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	    statistic_increment(select_scan_count, &LOCK_status);
	  }
	}
	else
	{
	  if (tab->select && tab->select->quick)
	  {
	    statistic_increment(select_full_range_join_count, &LOCK_status);
	  }
	  else
	  {
3671
	    join->thd->server_status|=SERVER_QUERY_NO_INDEX_USED;
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	    statistic_increment(select_full_join_count, &LOCK_status);
	  }
	}
3675
	if (!table->no_keyread)
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	{
3677
	  if (tab->select && tab->select->quick &&
3678
	      table->used_keys.is_set(tab->select->quick->index))
3679 3680 3681 3682
	  {
	    table->key_read=1;
	    table->file->extra(HA_EXTRA_KEYREAD);
	  }
3683
	  else if (!table->used_keys.is_clear_all() && ! (tab->select && tab->select->quick))
3684
	  {					// Only read index tree
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3685
	    tab->index=find_shortest_key(table, & table->used_keys);
3686
	    tab->table->file->index_init(tab->index);
3687
	    tab->read_first_record= join_read_first;
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	    tab->type=JT_NEXT;		// Read with index_first / index_next
	  }
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	}
      }
      break;
    default:
      DBUG_PRINT("error",("Table type %d found",tab->type)); /* purecov: deadcode */
      break;					/* purecov: deadcode */
    case JT_UNKNOWN:
    case JT_MAYBE_REF:
      abort();					/* purecov: deadcode */
    }
  }
  join->join_tab[join->tables-1].next_select=0; /* Set by do_select */
  DBUG_VOID_RETURN;
}


3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727
/*
  Give error if we some tables are done with a full join

  SYNOPSIS
    error_if_full_join()
    join		Join condition

  USAGE
   This is used by multi_table_update and multi_table_delete when running
   in safe mode

 RETURN VALUES
   0	ok
   1	Error (full join used)
*/

bool error_if_full_join(JOIN *join)
{
  for (JOIN_TAB *tab=join->join_tab, *end=join->join_tab+join->tables;
       tab < end;
       tab++)
  {
3728
    if (tab->type == JT_ALL && (!tab->select || !tab->select->quick))
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    {
      my_error(ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE,MYF(0));
      return(1);
    }
  }
  return(0);
}


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/*
  Free resources of given join

  SYNOPSIS
    JOIN::join_free()
    fill - true if we should free all resources, call with full==1 should be
           last, before it this function can be called with full==0

  NOTE: with subquery this function definitely will be called several times,
    but even for simple query it can be called several times.
*/
void
JOIN::join_free(bool full)
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{
  JOIN_TAB *tab,*end;
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  DBUG_ENTER("join_free");
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3755
  if (table)
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  {
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    /*
      Only a sorted table may be cached.  This sorted table is always the
      first non const table in join->table
    */
3761
    if (tables > const_tables) // Test for not-const tables
3762
    {
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      free_io_cache(table[const_tables]);
      filesort_free_buffers(table[const_tables]);
3765
    }
3766
    if (!full && select_lex->uncacheable)
3767
    {
3768
      for (tab= join_tab, end= tab+tables; tab != end; tab++)
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      {
	if (tab->table)
	{
	  /* Don't free index if we are using read_record */
	  if (!tab->read_record.table)
	    tab->table->file->index_end();
	}
      }
3777
    }
3778
    else
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    {
3780
      for (tab= join_tab, end= tab+tables; tab != end; tab++)
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      {
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	delete tab->select;
	delete tab->quick;
	tab->select=0;
	tab->quick=0;
3786
	x_free(tab->cache.buff);
3787
	tab->cache.buff= 0;
3788
	if (tab->table)
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	{
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	  if (tab->table->key_read)
	  {
	    tab->table->key_read= 0;
	    tab->table->file->extra(HA_EXTRA_NO_KEYREAD);
	  }
	  /* Don't free index if we are using read_record */
	  if (!tab->read_record.table)
	    tab->table->file->index_end();
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	  /*
	    We need to reset this for next select
	    (Tested in part_of_refkey)
	  */
	  tab->table->reginfo.join_tab= 0;
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	}
3804
	end_read_record(&tab->read_record);
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      }
3806
      table= 0;
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    }
  }
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  /*
    We are not using tables anymore
    Unlock all tables. We may be in an INSERT .... SELECT statement.
  */
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  if ((full || !select_lex->uncacheable) &&
      lock && thd->lock &&
      !(select_options & SELECT_NO_UNLOCK))
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  {
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    mysql_unlock_read_tables(thd, lock);// Don't free join->lock
    lock=0;
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  }
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  if (full)
  {
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    group_fields.delete_elements();
    tmp_table_param.copy_funcs.delete_elements();
    tmp_table_param.cleanup();
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  }
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  DBUG_VOID_RETURN;
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}


/*****************************************************************************
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  Remove the following expressions from ORDER BY and GROUP BY:
  Constant expressions
  Expression that only uses tables that are of type EQ_REF and the reference
  is in the ORDER list or if all refereed tables are of the above type.

  In the following, the X field can be removed:
  SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t1.a,t2.X
  SELECT * FROM t1,t2,t3 WHERE t1.a=t2.a AND t2.b=t3.b ORDER BY t1.a,t3.X

  These can't be optimized:
  SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t2.X,t1.a
  SELECT * FROM t1,t2 WHERE t1.a=t2.a AND t1.b=t2.b ORDER BY t1.a,t2.c
  SELECT * FROM t1,t2 WHERE t1.a=t2.a ORDER BY t2.b,t1.a
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*****************************************************************************/

static bool
eq_ref_table(JOIN *join, ORDER *start_order, JOIN_TAB *tab)
{
  if (tab->cached_eq_ref_table)			// If cached
    return tab->eq_ref_table;
  tab->cached_eq_ref_table=1;
  if (tab->type == JT_CONST)			// We can skip const tables
    return (tab->eq_ref_table=1);		/* purecov: inspected */
  if (tab->type != JT_EQ_REF)
    return (tab->eq_ref_table=0);		// We must use this
  Item **ref_item=tab->ref.items;
  Item **end=ref_item+tab->ref.key_parts;
  uint found=0;
  table_map map=tab->table->map;

  for (; ref_item != end ; ref_item++)
  {
    if (! (*ref_item)->const_item())
    {						// Not a const ref
      ORDER *order;
      for (order=start_order ; order ; order=order->next)
      {
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	if ((*ref_item)->eq(order->item[0],0))
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	  break;
      }
      if (order)
      {
	found++;
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	DBUG_ASSERT(!(order->used & map));
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	order->used|=map;
	continue;				// Used in ORDER BY
      }
      if (!only_eq_ref_tables(join,start_order, (*ref_item)->used_tables()))
	return (tab->eq_ref_table=0);
    }
  }
  /* Check that there was no reference to table before sort order */
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  for (; found && start_order ; start_order=start_order->next)
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  {
    if (start_order->used & map)
    {
      found--;
      continue;
    }
    if (start_order->depend_map & map)
      return (tab->eq_ref_table=0);
  }
  return tab->eq_ref_table=1;
}


static bool
only_eq_ref_tables(JOIN *join,ORDER *order,table_map tables)
{
  if (specialflag &  SPECIAL_SAFE_MODE)
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    return 0;			// skip this optimize /* purecov: inspected */
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  for (JOIN_TAB **tab=join->map2table ; tables ; tab++, tables>>=1)
  {
    if (tables & 1 && !eq_ref_table(join, order, *tab))
      return 0;
  }
  return 1;
}


/* Update the dependency map for the tables */

static void update_depend_map(JOIN *join)
{
  JOIN_TAB *join_tab=join->join_tab, *end=join_tab+join->tables;

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  for (; join_tab != end ; join_tab++)
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  {
    TABLE_REF *ref= &join_tab->ref;
    table_map depend_map=0;
    Item **item=ref->items;
    uint i;
    for (i=0 ; i < ref->key_parts ; i++,item++)
      depend_map|=(*item)->used_tables();
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    ref->depend_map=depend_map & ~OUTER_REF_TABLE_BIT;
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    depend_map&= ~OUTER_REF_TABLE_BIT;
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    for (JOIN_TAB **tab=join->map2table;
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	 depend_map ;
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	 tab++,depend_map>>=1 )
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    {
      if (depend_map & 1)
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	ref->depend_map|=(*tab)->ref.depend_map;
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    }
  }
}


/* Update the dependency map for the sort order */

static void update_depend_map(JOIN *join, ORDER *order)
{
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  for (; order ; order=order->next)
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  {
    table_map depend_map;
    order->item[0]->update_used_tables();
    order->depend_map=depend_map=order->item[0]->used_tables();
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    // Not item_sum(), RAND() and no reference to table outside of sub select
    if (!(order->depend_map & (OUTER_REF_TABLE_BIT | RAND_TABLE_BIT)))
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    {
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      for (JOIN_TAB **tab=join->map2table;
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	   depend_map ;
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	   tab++, depend_map>>=1)
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      {
	if (depend_map & 1)
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	  order->depend_map|=(*tab)->ref.depend_map;
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      }
    }
  }
}


/*
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  simple_order is set to 1 if sort_order only uses fields from head table
  and the head table is not a LEFT JOIN table
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*/

static ORDER *
remove_const(JOIN *join,ORDER *first_order, COND *cond, bool *simple_order)
{
  if (join->tables == join->const_tables)
    return 0;					// No need to sort
  DBUG_ENTER("remove_const");
  ORDER *order,**prev_ptr;
  table_map first_table= join->join_tab[join->const_tables].table->map;
  table_map not_const_tables= ~join->const_table_map;
  table_map ref;
  prev_ptr= &first_order;
  *simple_order= join->join_tab[join->const_tables].on_expr ? 0 : 1;

  /* NOTE: A variable of not_const_tables ^ first_table; breaks gcc 2.7 */

  update_depend_map(join, first_order);
  for (order=first_order; order ; order=order->next)
  {
    table_map order_tables=order->item[0]->used_tables();
    if (order->item[0]->with_sum_func)
      *simple_order=0;				// Must do a temp table to sort
    else if (!(order_tables & not_const_tables))
    {
      DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
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      continue;					// skip const item
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    }
    else
    {
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      if (order_tables & (RAND_TABLE_BIT | OUTER_REF_TABLE_BIT))
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	*simple_order=0;
      else
      {
	Item *comp_item=0;
	if (cond && const_expression_in_where(cond,order->item[0], &comp_item))
	{
	  DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
	  continue;
	}
	if ((ref=order_tables & (not_const_tables ^ first_table)))
	{
	  if (only_eq_ref_tables(join,first_order,ref))
	  {
	    DBUG_PRINT("info",("removing: %s", order->item[0]->full_name()));
	    continue;
	  }
	  *simple_order=0;			// Must do a temp table to sort
	}
      }
    }
    *prev_ptr= order;				// use this entry
    prev_ptr= &order->next;
  }
  *prev_ptr=0;
  if (!first_order)				// Nothing to sort/group
    *simple_order=1;
  DBUG_PRINT("exit",("simple_order: %d",(int) *simple_order));
  DBUG_RETURN(first_order);
}

4026

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static int
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return_zero_rows(JOIN *join, select_result *result,TABLE_LIST *tables,
		 List<Item> &fields, bool send_row, uint select_options,
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		 const char *info, Item *having, Procedure *procedure,
		 SELECT_LEX_UNIT *unit)
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{
  DBUG_ENTER("return_zero_rows");

  if (select_options & SELECT_DESCRIBE)
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  {
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    select_describe(join, false, false, false, info);
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    DBUG_RETURN(0);
  }
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  if (procedure)
  {
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    if (result->prepare(fields, unit))		// This hasn't been done yet
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      DBUG_RETURN(-1);
  }
  if (send_row)
  {
    for (TABLE_LIST *table=tables; table ; table=table->next)
      mark_as_null_row(table->table);		// All fields are NULL
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    if (having && having->val_int() == 0)
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      send_row=0;
  }
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  if (!(result->send_fields(fields,1)))
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  {
    if (send_row)
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    {
      List_iterator_fast<Item> it(fields);
      Item *item;
      while ((item= it++))
	item->no_rows_in_result();
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      result->send_data(fields);
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    }
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    if (tables)				// Not from do_select()
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    {
      /* Close open cursors */
      for (TABLE_LIST *table=tables; table ; table=table->next)
	table->table->file->index_end();
    }
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    result->send_eof();				// Should be safe
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  }
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  /* Update results for FOUND_ROWS */
  join->thd->limit_found_rows= join->thd->examined_row_count= 0;
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  DBUG_RETURN(0);
}


static void clear_tables(JOIN *join)
{
  for (uint i=0 ; i < join->tables ; i++)
    mark_as_null_row(join->table[i]);		// All fields are NULL
}

/*****************************************************************************
4084 4085 4086 4087 4088 4089
  Make som simple condition optimization:
  If there is a test 'field = const' change all refs to 'field' to 'const'
  Remove all dummy tests 'item = item', 'const op const'.
  Remove all 'item is NULL', when item can never be null!
  item->marker should be 0 for all items on entry
  Return in cond_value FALSE if condition is impossible (1 = 2)
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*****************************************************************************/

class COND_CMP :public ilink {
public:
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  static void *operator new(size_t size) {return (void*) sql_alloc((uint) size); }
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  static void operator delete(void *ptr __attribute__((unused)),
			      size_t size __attribute__((unused))) {} /*lint -e715 */

  Item *and_level;
  Item_func *cmp_func;
  COND_CMP(Item *a,Item_func *b) :and_level(a),cmp_func(b) {}
};

#ifdef __GNUC__
template class I_List<COND_CMP>;
template class I_List_iterator<COND_CMP>;
template class List<Item_func_match>;
template class List_iterator<Item_func_match>;
#endif

/*
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  change field = field to field = const for each found field = const in the
  and_level
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*/

static void
change_cond_ref_to_const(I_List<COND_CMP> *save_list,Item *and_father,
			 Item *cond, Item *field, Item *value)
{
  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= ((Item_cond*) cond)->functype() ==
      Item_func::COND_AND_FUNC;
    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
    Item *item;
    while ((item=li++))
      change_cond_ref_to_const(save_list,and_level ? cond : item, item,
			       field, value);
    return;
  }
  if (cond->eq_cmp_result() == Item::COND_OK)
    return;					// Not a boolean function

  Item_bool_func2 *func=  (Item_bool_func2*) cond;
  Item *left_item=  func->arguments()[0];
  Item *right_item= func->arguments()[1];
  Item_func::Functype functype=  func->functype();

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  if (right_item->eq(field,0) && left_item != value)
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  {
    Item *tmp=value->new_item();
    if (tmp)
    {
      func->arguments()[1] = tmp;
      func->update_used_tables();
      if ((functype == Item_func::EQ_FUNC || functype == Item_func::EQUAL_FUNC)
	  && and_father != cond && !left_item->const_item())
      {
	cond->marker=1;
	COND_CMP *tmp2;
	if ((tmp2=new COND_CMP(and_father,func)))
	  save_list->push_back(tmp2);
      }
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      func->set_cmp_func();
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    }
  }
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  else if (left_item->eq(field,0) && right_item != value)
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  {
    Item *tmp=value->new_item();
    if (tmp)
    {
      func->arguments()[0] = value = tmp;
      func->update_used_tables();
      if ((functype == Item_func::EQ_FUNC || functype == Item_func::EQUAL_FUNC)
	  && and_father != cond && !right_item->const_item())
      {
	func->arguments()[0] = func->arguments()[1]; // For easy check
	func->arguments()[1] = value;
	cond->marker=1;
	COND_CMP *tmp2;
	if ((tmp2=new COND_CMP(and_father,func)))
	  save_list->push_back(tmp2);
      }
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      func->set_cmp_func();
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    }
  }
}

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/*
  Remove additional condition inserted by IN/ALL/ANY transformation

  SYNOPSIS
    remove_additional_cond()
    conds - condition for processing

  RETURN VALUES
    new conditions
*/

static Item *remove_additional_cond(Item* conds)
{
  if (conds->name == in_additional_cond)
    return 0;
  if (conds->type() == Item::COND_ITEM)
  {
    Item_cond *cnd= (Item_cond*) conds;
    List_iterator<Item> li(*(cnd->argument_list()));
    Item *item;
    while ((item= li++))
    {
      if (item->name == in_additional_cond)
      {
	li.remove();
	if (cnd->argument_list()->elements == 1)
	  return cnd->argument_list()->head();
	return conds;
      }
    }
  }
  return conds;
}
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static void
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propagate_cond_constants(I_List<COND_CMP> *save_list,COND *and_father,
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			 COND *cond)
{
  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= ((Item_cond*) cond)->functype() ==
      Item_func::COND_AND_FUNC;
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    Item *item;
    I_List<COND_CMP> save;
    while ((item=li++))
    {
      propagate_cond_constants(&save,and_level ? cond : item, item);
    }
    if (and_level)
    {						// Handle other found items
      I_List_iterator<COND_CMP> cond_itr(save);
      COND_CMP *cond_cmp;
      while ((cond_cmp=cond_itr++))
	if (!cond_cmp->cmp_func->arguments()[0]->const_item())
	  change_cond_ref_to_const(&save,cond_cmp->and_level,
				   cond_cmp->and_level,
				   cond_cmp->cmp_func->arguments()[0],
				   cond_cmp->cmp_func->arguments()[1]);
    }
  }
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  else if (and_father != cond && !cond->marker)		// In a AND group
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  {
    if (cond->type() == Item::FUNC_ITEM &&
	(((Item_func*) cond)->functype() == Item_func::EQ_FUNC ||
	 ((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC))
    {
      Item_func_eq *func=(Item_func_eq*) cond;
      bool left_const= func->arguments()[0]->const_item();
      bool right_const=func->arguments()[1]->const_item();
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      if (!(left_const && right_const) &&
	  (func->arguments()[0]->result_type() ==
	   (func->arguments()[1]->result_type())))
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      {
	if (right_const)
	{
	  func->arguments()[1]=resolve_const_item(func->arguments()[1],
						  func->arguments()[0]);
	  func->update_used_tables();
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	  change_cond_ref_to_const(save_list,and_father,and_father,
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				   func->arguments()[0],
				   func->arguments()[1]);
	}
	else if (left_const)
	{
	  func->arguments()[0]=resolve_const_item(func->arguments()[0],
						  func->arguments()[1]);
	  func->update_used_tables();
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	  change_cond_ref_to_const(save_list,and_father,and_father,
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				   func->arguments()[1],
				   func->arguments()[0]);
	}
      }
    }
  }
}


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/*
  Eliminate NOT functions from the condition tree.

  SYNPOSIS
    eliminate_not_funcs()
    cond	condition tree

  DESCRIPTION
    Eliminate NOT functions from the condition tree where it's possible.
    Recursively traverse condition tree to find all NOT functions.
    Call neg_transformer() method for negated arguments.

  NOTE
    If neg_transformer() returned a new condition we call fix_fields().
    We don't delete any items as it's not needed. They will be deleted 
    later at once.

  RETURN
    New condition tree
*/

COND *eliminate_not_funcs(COND *cond)
{
  if (!cond)
    return cond;
  if (cond->type() == Item::COND_ITEM)		/* OR or AND */
  {
    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
    Item *item;
    while ((item= li++))
    {
      Item *new_item= eliminate_not_funcs(item);
      if (item != new_item)
	VOID(li.replace(new_item));	/* replace item with a new condition */
    }
  }
  else if (cond->type() == Item::FUNC_ITEM &&	/* 'NOT' operation? */
	   ((Item_func*) cond)->functype() == Item_func::NOT_FUNC)
  {
    COND *new_cond= ((Item_func*) cond)->arguments()[0]->neg_transformer();
    if (new_cond)
    {
      /*
        Here we can delete the NOT function. Something like: delete cond;
        But we don't need to do it. All items will be deleted later at once.
      */
      new_cond->fix_fields(current_thd, 0, &new_cond);
      cond= new_cond;
    }
  }
  return cond;
}


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static COND *
optimize_cond(COND *conds,Item::cond_result *cond_value)
{
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  DBUG_ENTER("optimize_cond");
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  if (!conds)
  {
    *cond_value= Item::COND_TRUE;
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    DBUG_RETURN(conds);
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  }
  DBUG_EXECUTE("where",print_where(conds,"original"););
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  /* eliminate NOT operators */
  conds= eliminate_not_funcs(conds);
  DBUG_EXECUTE("where", print_where(conds, "after negation elimination"););
  /* change field = field to field = const for each found field = const */
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  propagate_cond_constants((I_List<COND_CMP> *) 0,conds,conds);
  /*
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    Remove all instances of item == item
    Remove all and-levels where CONST item != CONST item
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  */
  DBUG_EXECUTE("where",print_where(conds,"after const change"););
  conds=remove_eq_conds(conds,cond_value) ;
  DBUG_EXECUTE("info",print_where(conds,"after remove"););
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  DBUG_RETURN(conds);
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}


/*
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  Remove const and eq items. Return new item, or NULL if no condition
  cond_value is set to according:
  COND_OK    query is possible (field = constant)
  COND_TRUE  always true	( 1 = 1 )
  COND_FALSE always false	( 1 = 2 )
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*/

static COND *
remove_eq_conds(COND *cond,Item::cond_result *cond_value)
{
  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= ((Item_cond*) cond)->functype()
      == Item_func::COND_AND_FUNC;
    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
    Item::cond_result tmp_cond_value;
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    bool should_fix_fields=0;
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    *cond_value=Item::COND_UNDEF;
    Item *item;
    while ((item=li++))
    {
      Item *new_item=remove_eq_conds(item,&tmp_cond_value);
      if (!new_item)
      {
#ifdef DELETE_ITEMS
	delete item;				// This may be shared
#endif
	li.remove();
      }
      else if (item != new_item)
      {
#ifdef DELETE_ITEMS
	delete item;				// This may be shared
#endif
	VOID(li.replace(new_item));
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	should_fix_fields=1;
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      }
      if (*cond_value == Item::COND_UNDEF)
	*cond_value=tmp_cond_value;
      switch (tmp_cond_value) {
      case Item::COND_OK:			// Not TRUE or FALSE
	if (and_level || *cond_value == Item::COND_FALSE)
	  *cond_value=tmp_cond_value;
	break;
      case Item::COND_FALSE:
	if (and_level)
	{
	  *cond_value=tmp_cond_value;
	  return (COND*) 0;			// Always false
	}
	break;
      case Item::COND_TRUE:
	if (!and_level)
	{
	  *cond_value= tmp_cond_value;
	  return (COND*) 0;			// Always true
	}
	break;
      case Item::COND_UNDEF:			// Impossible
	break; /* purecov: deadcode */
      }
    }
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    if (should_fix_fields)
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      cond->fix_fields(current_thd,0, &cond);
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    if (!((Item_cond*) cond)->argument_list()->elements ||
	*cond_value != Item::COND_OK)
      return (COND*) 0;
    if (((Item_cond*) cond)->argument_list()->elements == 1)
    {						// Remove list
      item= ((Item_cond*) cond)->argument_list()->head();
      ((Item_cond*) cond)->argument_list()->empty();
      return item;
    }
  }
  else if (cond->type() == Item::FUNC_ITEM &&
	   ((Item_func*) cond)->functype() == Item_func::ISNULL_FUNC)
  {
    /*
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      Handles this special case for some ODBC applications:
      The are requesting the row that was just updated with a auto_increment
      value with this construct:

      SELECT * from table_name where auto_increment_column IS NULL
      This will be changed to:
      SELECT * from table_name where auto_increment_column = LAST_INSERT_ID
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    */

    Item_func_isnull *func=(Item_func_isnull*) cond;
    Item **args= func->arguments();
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    THD *thd=current_thd;
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    if (args[0]->type() == Item::FIELD_ITEM)
    {
      Field *field=((Item_field*) args[0])->field;
      if (field->flags & AUTO_INCREMENT_FLAG && !field->table->maybe_null &&
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	  (thd->options & OPTION_AUTO_IS_NULL) &&
	  thd->insert_id())
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      {
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#ifndef EMBEDDED_LIBRARY
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	query_cache_abort(&thd->net);
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#endif
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	COND *new_cond;
	if ((new_cond= new Item_func_eq(args[0],
					new Item_int("last_insert_id()",
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						     thd->insert_id(),
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						     21))))
	{
	  cond=new_cond;
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	  cond->fix_fields(thd, 0, &cond);
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	}
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	thd->insert_id(0);		// Clear for next request
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      }
      /* fix to replace 'NULL' dates with '0' (shreeve@uci.edu) */
      else if (((field->type() == FIELD_TYPE_DATE) ||
		(field->type() == FIELD_TYPE_DATETIME)) &&
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		(field->flags & NOT_NULL_FLAG) &&
	       !field->table->maybe_null)
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      {
	COND *new_cond;
	if ((new_cond= new Item_func_eq(args[0],new Item_int("0", 0, 2))))
	{
	  cond=new_cond;
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	  cond->fix_fields(thd, 0, &cond);
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	}
      }
    }
  }
  else if (cond->const_item())
  {
    *cond_value= eval_const_cond(cond) ? Item::COND_TRUE : Item::COND_FALSE;
    return (COND*) 0;
  }
  else if ((*cond_value= cond->eq_cmp_result()) != Item::COND_OK)
  {						// boolan compare function
    Item *left_item=	((Item_func*) cond)->arguments()[0];
    Item *right_item= ((Item_func*) cond)->arguments()[1];
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    if (left_item->eq(right_item,1))
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    {
      if (!left_item->maybe_null ||
	  ((Item_func*) cond)->functype() == Item_func::EQUAL_FUNC)
	return (COND*) 0;			// Compare of identical items
    }
  }
  *cond_value=Item::COND_OK;
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  return cond;					// Point at next and level
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}

/*
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  Return 1 if the item is a const value in all the WHERE clause
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*/

static bool
const_expression_in_where(COND *cond, Item *comp_item, Item **const_item)
{
  if (cond->type() == Item::COND_ITEM)
  {
    bool and_level= (((Item_cond*) cond)->functype()
		     == Item_func::COND_AND_FUNC);
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    List_iterator_fast<Item> li(*((Item_cond*) cond)->argument_list());
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    Item *item;
    while ((item=li++))
    {
      bool res=const_expression_in_where(item, comp_item, const_item);
      if (res)					// Is a const value
      {
	if (and_level)
	  return 1;
      }
      else if (!and_level)
	return 0;
    }
    return and_level ? 0 : 1;
  }
  else if (cond->eq_cmp_result() != Item::COND_OK)
  {						// boolan compare function
    Item_func* func= (Item_func*) cond;
    if (func->functype() != Item_func::EQUAL_FUNC &&
	func->functype() != Item_func::EQ_FUNC)
      return 0;
    Item *left_item=	((Item_func*) cond)->arguments()[0];
    Item *right_item= ((Item_func*) cond)->arguments()[1];
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    if (left_item->eq(comp_item,1))
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    {
      if (right_item->const_item())
      {
	if (*const_item)
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	  return right_item->eq(*const_item, 1);
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	*const_item=right_item;
	return 1;
      }
    }
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    else if (right_item->eq(comp_item,1))
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    {
      if (left_item->const_item())
      {
	if (*const_item)
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	  return left_item->eq(*const_item, 1);
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	*const_item=left_item;
	return 1;
      }
    }
  }
  return 0;
}


/****************************************************************************
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  Create internal temporary table
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****************************************************************************/

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/*
  Create field for temporary table from given field
  
  SYNOPSIS
    create_tmp_field_from_field()
    thd			Thread handler
    org_field           field from which new field will be created
    item		Item to create a field for
    table		Temporary table
    modify_item	        1 if item->result_field should point to new item.
			This is relevent for how fill_record() is going to
			work:
			If modify_item is 1 then fill_record() will update
			the record in the original table.
			If modify_item is 0 then fill_record() will update
			the temporary table

  RETURN
    0			on error
    new_created field
*/
static Field* create_tmp_field_from_field(THD *thd,
					  Field* org_field,
					  Item *item,
					  TABLE *table,
					  bool modify_item)
{
  Field *new_field;

  // The following should always be true
  if ((new_field= org_field->new_field(&thd->mem_root,table)))
  {
    if (modify_item)
      ((Item_field *)item)->result_field= new_field;
    else
      new_field->field_name= item->name;
    if (org_field->maybe_null())
      new_field->flags&= ~NOT_NULL_FLAG;	// Because of outer join
    if (org_field->type() == FIELD_TYPE_VAR_STRING)
      table->db_create_options|= HA_OPTION_PACK_RECORD;
  }
  return new_field;
}

/*
  Create field for temporary table using type of given item
  
  SYNOPSIS
    create_tmp_field_from_item()
    thd			Thread handler
    item		Item to create a field for
    table		Temporary table
    copy_func		If set and item is a function, store copy of item
			in this array
    modify_item		1 if item->result_field should point to new item.
			This is relevent for how fill_record() is going to
			work:
			If modify_item is 1 then fill_record() will update
			the record in the original table.
			If modify_item is 0 then fill_record() will update
			the temporary table

  RETURN
    0			on error
    new_created field
*/
static Field* create_tmp_field_from_item(THD *thd,
					 Item *item,
					 TABLE *table,
					 Item ***copy_func,
					 bool modify_item)
{
  bool maybe_null=item->maybe_null;
  Field *new_field;
  LINT_INIT(new_field);

  switch (item->result_type()) {
  case REAL_RESULT:
    new_field=new Field_double(item->max_length, maybe_null,
			       item->name, table, item->decimals);
    break;
  case INT_RESULT:
    new_field=new Field_longlong(item->max_length, maybe_null,
				   item->name, table, item->unsigned_flag);
    break;
  case STRING_RESULT:
    if (item->max_length > 255)
      new_field=  new Field_blob(item->max_length, maybe_null,
				 item->name, table,
				 item->collation.collation);
    else
      new_field= new Field_string(item->max_length, maybe_null,
				  item->name, table,
				  item->collation.collation);
    break;
  case ROW_RESULT: 
  default: 
    // This case should never be choosen
    DBUG_ASSERT(0);
    new_field= 0; // to satisfy compiler (uninitialized variable)
    break;
  }
  if (copy_func && item->is_result_field())
    *((*copy_func)++) = item;			// Save for copy_funcs
  if (modify_item)
    item->set_result_field(new_field);
  return new_field;
}

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/*
  Create field for temporary table

  SYNOPSIS
    create_tmp_field()
    thd			Thread handler
    table		Temporary table
    item		Item to create a field for
    type		Type of item (normally item->type)
    copy_func		If set and item is a function, store copy of item
			in this array
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    from_field          if field will be created using other field as example,
                        pointer example field will be written here 
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    group		1 if we are going to do a relative group by on result
    modify_item		1 if item->result_field should point to new item.
			This is relevent for how fill_record() is going to
			work:
			If modify_item is 1 then fill_record() will update
			the record in the original table.
			If modify_item is 0 then fill_record() will update
			the temporary table
		       
  RETURN
    0			on error
    new_created field
*/

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Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
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			Item ***copy_func, Field **from_field,
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			bool group, bool modify_item)
{
  switch (type) {
  case Item::SUM_FUNC_ITEM:
  {
    Item_sum *item_sum=(Item_sum*) item;
    bool maybe_null=item_sum->maybe_null;
    switch (item_sum->sum_func()) {
    case Item_sum::AVG_FUNC:			/* Place for sum & count */
      if (group)
	return new Field_string(sizeof(double)+sizeof(longlong),
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				0, item->name,table,&my_charset_bin);
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      else
	return new Field_double(item_sum->max_length,maybe_null,
				item->name, table, item_sum->decimals);
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    case Item_sum::VARIANCE_FUNC:			/* Place for sum & count */
    case Item_sum::STD_FUNC:	
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      if (group)
	return	new Field_string(sizeof(double)*2+sizeof(longlong),
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				 0, item->name,table,&my_charset_bin);
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      else
	return new Field_double(item_sum->max_length, maybe_null,
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				item->name,table,item_sum->decimals);				
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    case Item_sum::UNIQUE_USERS_FUNC:
      return new Field_long(9,maybe_null,item->name,table,1);
    default:
      switch (item_sum->result_type()) {
      case REAL_RESULT:
	return new Field_double(item_sum->max_length,maybe_null,
				item->name,table,item_sum->decimals);
      case INT_RESULT:
	return new Field_longlong(item_sum->max_length,maybe_null,
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				  item->name,table,item->unsigned_flag);
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      case STRING_RESULT:
	if (item_sum->max_length > 255)
	  return  new Field_blob(item_sum->max_length,maybe_null,
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				 item->name,table,item->collation.collation);
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	return	new Field_string(item_sum->max_length,maybe_null,
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				 item->name,table,item->collation.collation);
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      case ROW_RESULT:
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      default:
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	// This case should never be choosen
	DBUG_ASSERT(0);
	return 0;
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      }
    }
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    thd->fatal_error();
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    return 0;					// Error
  }
  case Item::FIELD_ITEM:
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  case Item::DEFAULT_VALUE_ITEM:
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    return create_tmp_field_from_field(thd, (*from_field=
					     ((Item_field*) item)->field),
				       item, table, modify_item);
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  case Item::FUNC_ITEM:
  case Item::COND_ITEM:
  case Item::FIELD_AVG_ITEM:
  case Item::FIELD_STD_ITEM:
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  case Item::SUBSELECT_ITEM:
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    /* The following can only happen with 'CREATE TABLE ... SELECT' */
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  case Item::PROC_ITEM:
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  case Item::INT_ITEM:
  case Item::REAL_ITEM:
  case Item::STRING_ITEM:
  case Item::REF_ITEM:
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  case Item::NULL_ITEM:
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  case Item::VARBIN_ITEM:
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    return create_tmp_field_from_item(thd, item, table,
				      copy_func, modify_item);
  case Item::TYPE_HOLDER:
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  {
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    Field *example= ((Item_type_holder *)item)->example();
    if (example)
      return create_tmp_field_from_field(thd, example, item, table, 0);
    return create_tmp_field_from_item(thd, item, table, copy_func, 0);
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  }
  default:					// Dosen't have to be stored
    return 0;
  }
}


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/*
  Create a temp table according to a field list.
  Set distinct if duplicates could be removed
  Given fields field pointers are changed to point at tmp_table
  for send_fields
*/

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TABLE *
create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
		 ORDER *group, bool distinct, bool save_sum_fields,
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		 ulong select_options, ha_rows rows_limit,
		 char *table_alias)
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{
  TABLE *table;
  uint	i,field_count,reclength,null_count,null_pack_length,
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        hidden_null_count, hidden_null_pack_length, hidden_field_count,
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	blob_count,group_null_items;
  bool	using_unique_constraint=0;
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  bool  not_all_columns= !(select_options & TMP_TABLE_ALL_COLUMNS);
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  char	*tmpname,path[FN_REFLEN];
  byte	*pos,*group_buff;
  uchar *null_flags;
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  Field **reg_field, **from_field, **blob_field;
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  Copy_field *copy=0;
  KEY *keyinfo;
  KEY_PART_INFO *key_part_info;
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  Item **copy_func;
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  MI_COLUMNDEF *recinfo;
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  uint temp_pool_slot=MY_BIT_NONE;
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  DBUG_ENTER("create_tmp_table");
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  DBUG_PRINT("enter",("distinct: %d  save_sum_fields: %d  rows_limit: %lu  group: %d",
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		      (int) distinct, (int) save_sum_fields,
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		      (ulong) rows_limit,test(group)));
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  statistic_increment(created_tmp_tables, &LOCK_status);
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  if (use_temp_pool)
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    temp_pool_slot = bitmap_set_next(&temp_pool);
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  if (temp_pool_slot != MY_BIT_NONE) // we got a slot
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    sprintf(path, "%s%s_%lx_%i", mysql_tmpdir, tmp_file_prefix,
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	    current_pid, temp_pool_slot);
  else // if we run out of slots or we are not using tempool
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    sprintf(path,"%s%s%lx_%lx_%x",mysql_tmpdir,tmp_file_prefix,current_pid,
            thd->thread_id, thd->tmp_table++);

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  if (group)
  {
    if (!param->quick_group)
      group=0;					// Can't use group key
    else for (ORDER *tmp=group ; tmp ; tmp=tmp->next)
4840
    {
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4841
      (*tmp->item)->marker=4;			// Store null in key
4842 4843 4844
      if ((*tmp->item)->max_length >= MAX_CHAR_WIDTH)
	using_unique_constraint=1;
    }
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4845 4846
    if (param->group_length >= MAX_BLOB_WIDTH)
      using_unique_constraint=1;
4847 4848
    if (group)
      distinct=0;				// Can't use distinct
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4849 4850 4851
  }

  field_count=param->field_count+param->func_count+param->sum_func_count;
4852
  hidden_field_count=param->hidden_field_count;
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4853 4854
  if (!my_multi_malloc(MYF(MY_WME),
		       &table,sizeof(*table),
4855 4856 4857
		       &reg_field,  sizeof(Field*)*(field_count+1),
		       &blob_field, sizeof(Field*)*(field_count+1),
		       &from_field, sizeof(Field*)*field_count,
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4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868
		       &copy_func,sizeof(*copy_func)*(param->func_count+1),
		       &param->keyinfo,sizeof(*param->keyinfo),
		       &key_part_info,
		       sizeof(*key_part_info)*(param->group_parts+1),
		       &param->start_recinfo,
		       sizeof(*param->recinfo)*(field_count*2+4),
		       &tmpname,(uint) strlen(path)+1,
		       &group_buff,group && ! using_unique_constraint ?
		       param->group_length : 0,
		       NullS))
  {
4869
    bitmap_clear_bit(&temp_pool, temp_pool_slot);
4870
    DBUG_RETURN(NULL);				/* purecov: inspected */
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4871 4872 4873
  }
  if (!(param->copy_field=copy=new Copy_field[field_count]))
  {
4874
    bitmap_clear_bit(&temp_pool, temp_pool_slot);
4875 4876
    my_free((gptr) table,MYF(0));		/* purecov: inspected */
    DBUG_RETURN(NULL);				/* purecov: inspected */
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4877
  }
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4878
  param->items_to_copy= copy_func;
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4879 4880 4881 4882 4883 4884 4885
  strmov(tmpname,path);
  /* make table according to fields */

  bzero((char*) table,sizeof(*table));
  bzero((char*) reg_field,sizeof(Field*)*(field_count+1));
  bzero((char*) from_field,sizeof(Field*)*field_count);
  table->field=reg_field;
4886
  table->blob_field= (Field_blob**) blob_field;
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4887
  table->real_name=table->path=tmpname;
4888
  table->table_name= table_alias;
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4889 4890 4891 4892
  table->reginfo.lock_type=TL_WRITE;	/* Will be updated */
  table->db_stat=HA_OPEN_KEYFILE+HA_OPEN_RNDFILE;
  table->blob_ptr_size=mi_portable_sizeof_char_ptr;
  table->map=1;
4893
  table->tmp_table= TMP_TABLE;
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4894
  table->db_low_byte_first=1;			// True for HEAP and MyISAM
4895
  table->temp_pool_slot = temp_pool_slot;
4896
  table->copy_blobs= 1;
4897 4898 4899 4900 4901 4902
  table->keys_for_keyread.init();
  table->keys_in_use.init();
  table->read_only_keys.init();
  table->quick_keys.init();
  table->used_keys.init();
  table->keys_in_use_for_query.init();
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4903

4904
  /* Calculate which type of fields we will store in the temporary table */
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4905

4906 4907
  reclength=blob_count=null_count=hidden_null_count=group_null_items=0;
  param->using_indirect_summary_function=0;
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4908

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4909
  List_iterator_fast<Item> li(fields);
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4910 4911
  Item *item;
  Field **tmp_from_field=from_field;
4912
  while ((item=li++))
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4913 4914
  {
    Item::Type type=item->type();
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4915
    if (not_all_columns)
4916
    {
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4917 4918 4919 4920 4921 4922 4923 4924 4925 4926
      if (item->with_sum_func && type != Item::SUM_FUNC_ITEM)
      {
	/*
	  Mark that the we have ignored an item that refers to a summary
	  function. We need to know this if someone is going to use
	  DISTINCT on the result.
	*/
	param->using_indirect_summary_function=1;
	continue;
      }
4927
      if (item->const_item() && (int) hidden_field_count <= 0)
4928
        continue; // We don't have to store this
4929
    }
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4930 4931 4932 4933 4934 4935 4936 4937 4938
    if (type == Item::SUM_FUNC_ITEM && !group && !save_sum_fields)
    {						/* Can't calc group yet */
      ((Item_sum*) item)->result_field=0;
      for (i=0 ; i < ((Item_sum*) item)->arg_count ; i++)
      {
	Item *arg= ((Item_sum*) item)->args[i];
	if (!arg->const_item())
	{
	  Field *new_field=
4939 4940
	    create_tmp_field(thd, table,arg,arg->type(),&copy_func,
			     tmp_from_field, group != 0,not_all_columns);
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4941 4942 4943 4944 4945 4946 4947 4948
	  if (!new_field)
	    goto err;					// Should be OOM
	  tmp_from_field++;
	  *(reg_field++)= new_field;
	  reclength+=new_field->pack_length();
	  if (!(new_field->flags & NOT_NULL_FLAG))
	    null_count++;
	  if (new_field->flags & BLOB_FLAG)
4949 4950
	  {
	    *blob_field++= new_field;
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4951
	    blob_count++;
4952
	  }
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	  ((Item_sum*) item)->args[i]= new Item_field(new_field);
	}
      }
    }
    else
    {
4959 4960 4961 4962 4963 4964 4965 4966 4967 4968
      /*
	The last parameter to create_tmp_field() is a bit tricky:

	We need to set it to 0 in union, to get fill_record() to modify the
	temporary table.
	We need to set it to 1 on multi-table-update and in select to
	write rows to the temporary table.
	We here distinguish between UNION and multi-table-updates by the fact
	that in the later case group is set to the row pointer.
      */
4969
      Field *new_field=create_tmp_field(thd, table, item,type, &copy_func,
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4970
					tmp_from_field, group != 0,
4971
					not_all_columns || group !=0);
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4972 4973
      if (!new_field)
      {
4974
	if (thd->is_fatal_error)
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4975 4976 4977 4978 4979 4980 4981 4982 4983 4984
	  goto err;				// Got OOM
	continue;				// Some kindf of const item
      }
      if (type == Item::SUM_FUNC_ITEM)
	((Item_sum *) item)->result_field= new_field;
      tmp_from_field++;
      reclength+=new_field->pack_length();
      if (!(new_field->flags & NOT_NULL_FLAG))
	null_count++;
      if (new_field->flags & BLOB_FLAG)
4985 4986
      {
	*blob_field++= new_field;
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4987
	blob_count++;
4988
      }
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4989 4990 4991 4992 4993 4994 4995
      if (item->marker == 4 && item->maybe_null)
      {
	group_null_items++;
	new_field->flags|= GROUP_FLAG;
      }
      *(reg_field++) =new_field;
    }
4996 4997
    if (!--hidden_field_count)
      hidden_null_count=null_count;
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4998
  }
4999
  DBUG_ASSERT(field_count >= (uint) (reg_field - table->field));
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5000
  field_count= (uint) (reg_field - table->field);
5001
  *blob_field= 0;				// End marker
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5002 5003

  /* If result table is small; use a heap */
5004
  if (blob_count || using_unique_constraint ||
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5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023
      (select_options & (OPTION_BIG_TABLES | SELECT_SMALL_RESULT)) ==
      OPTION_BIG_TABLES)
  {
    table->file=get_new_handler(table,table->db_type=DB_TYPE_MYISAM);
    if (group &&
	(param->group_parts > table->file->max_key_parts() ||
	 param->group_length > table->file->max_key_length()))
      using_unique_constraint=1;
  }
  else
  {
    table->file=get_new_handler(table,table->db_type=DB_TYPE_HEAP);
  }

  if (!using_unique_constraint)
    reclength+= group_null_items;	// null flag is stored separately

  table->blob_fields=blob_count;
  if (blob_count == 0)
5024 5025
  {
    /* We need to ensure that first byte is not 0 for the delete link */
5026
    if (param->hidden_field_count)
5027 5028 5029 5030 5031 5032 5033
      hidden_null_count++;
    else
      null_count++;
  }
  hidden_null_pack_length=(hidden_null_count+7)/8;
  null_pack_length=hidden_null_count+(null_count+7)/8;
  reclength+=null_pack_length;
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5034 5035 5036 5037 5038 5039 5040 5041
  if (!reclength)
    reclength=1;				// Dummy select

  table->fields=field_count;
  table->reclength=reclength;
  {
    uint alloc_length=ALIGN_SIZE(reclength+MI_UNIQUE_HASH_LENGTH+1);
    table->rec_buff_length=alloc_length;
5042
    if (!(table->record[0]= (byte *) my_malloc(alloc_length*3, MYF(MY_WME))))
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5043
      goto err;
5044
    table->record[1]= table->record[0]+alloc_length;
5045
    table->default_values= table->record[1]+alloc_length;
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5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060
  }
  copy_func[0]=0;				// End marker

  recinfo=param->start_recinfo;
  null_flags=(uchar*) table->record[0];
  pos=table->record[0]+ null_pack_length;
  if (null_pack_length)
  {
    bzero((byte*) recinfo,sizeof(*recinfo));
    recinfo->type=FIELD_NORMAL;
    recinfo->length=null_pack_length;
    recinfo++;
    bfill(null_flags,null_pack_length,255);	// Set null fields
  }
  null_count= (blob_count == 0) ? 1 : 0;
5061
  hidden_field_count=param->hidden_field_count;
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5062 5063 5064 5065 5066 5067 5068 5069 5070 5071
  for (i=0,reg_field=table->field; i < field_count; i++,reg_field++,recinfo++)
  {
    Field *field= *reg_field;
    uint length;
    bzero((byte*) recinfo,sizeof(*recinfo));

    if (!(field->flags & NOT_NULL_FLAG))
    {
      if (field->flags & GROUP_FLAG && !using_unique_constraint)
      {
5072 5073 5074 5075
	/*
	  We have to reserve one byte here for NULL bits,
	  as this is updated by 'end_update()'
	*/
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5076 5077 5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 5092 5093 5094 5095 5096 5097 5098 5099 5100 5101 5102 5103 5104 5105 5106 5107 5108 5109
	*pos++=0;				// Null is stored here
	recinfo->length=1;
	recinfo->type=FIELD_NORMAL;
	recinfo++;
	bzero((byte*) recinfo,sizeof(*recinfo));
      }
      else
      {
	recinfo->null_bit= 1 << (null_count & 7);
	recinfo->null_pos= null_count/8;
      }
      field->move_field((char*) pos,null_flags+null_count/8,
			1 << (null_count & 7));
      null_count++;
    }
    else
      field->move_field((char*) pos,(uchar*) 0,0);
    field->reset();
    if (from_field[i])
    {						/* Not a table Item */
      copy->set(field,from_field[i],save_sum_fields);
      copy++;
    }
    length=field->pack_length();
    pos+= length;

    /* Make entry for create table */
    recinfo->length=length;
    if (field->flags & BLOB_FLAG)
      recinfo->type= (int) FIELD_BLOB;
    else if (!field->zero_pack() &&
	     (field->type() == FIELD_TYPE_STRING ||
	      field->type() == FIELD_TYPE_VAR_STRING) &&
	     length >= 10 && blob_count)
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5110
      recinfo->type=FIELD_SKIP_ENDSPACE;
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5111 5112
    else
      recinfo->type=FIELD_NORMAL;
5113 5114
    if (!--hidden_field_count)
      null_count=(null_count+7) & ~7;		// move to next byte
5115 5116 5117

    // fix table name in field entry
    field->table_name= table->table_name;
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5118 5119
  }

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5120
  param->copy_field_end=copy;
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5121
  param->recinfo=recinfo;
5122
  store_record(table,default_values);			// Make empty default record
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5123

5124
  if (thd->variables.tmp_table_size == ~(ulong) 0)		// No limit
5125 5126 5127
    table->max_rows= ~(ha_rows) 0;
  else
    table->max_rows=(((table->db_type == DB_TYPE_HEAP) ?
5128 5129 5130
		      min(thd->variables.tmp_table_size,
			  thd->variables.max_heap_table_size) :
		      thd->variables.tmp_table_size)/ table->reclength);
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  set_if_bigger(table->max_rows,1);		// For dummy start options
  keyinfo=param->keyinfo;

  if (group)
  {
    DBUG_PRINT("info",("Creating group key in temporary table"));
    table->group=group;				/* Table is grouped by key */
    param->group_buff=group_buff;
    table->keys=1;
    table->uniques= test(using_unique_constraint);
    table->key_info=keyinfo;
    keyinfo->key_part=key_part_info;
    keyinfo->flags=HA_NOSAME;
    keyinfo->usable_key_parts=keyinfo->key_parts= param->group_parts;
    keyinfo->key_length=0;
    keyinfo->rec_per_key=0;
5147
    keyinfo->algorithm= HA_KEY_ALG_UNDEF;
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5148 5149
    for (; group ; group=group->next,key_part_info++)
    {
5150
      Field *field=(*group->item)->get_tmp_table_field();
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5151
      bool maybe_null=(*group->item)->maybe_null;
5152
      key_part_info->null_bit=0;
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5153 5154 5155 5156 5157 5158 5159 5160 5161 5162 5163
      key_part_info->field=  field;
      key_part_info->offset= field->offset();
      key_part_info->length= (uint16) field->pack_length();
      key_part_info->type=   (uint8) field->key_type();
      key_part_info->key_type =
	((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
	 (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT) ?
	0 : FIELDFLAG_BINARY;
      if (!using_unique_constraint)
      {
	group->buff=(char*) group_buff;
5164
	if (!(group->field=field->new_field(&thd->mem_root,table)))
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5165 5166 5167 5168
	  goto err; /* purecov: inspected */
	if (maybe_null)
	{
	  /*
5169 5170 5171 5172
	    To be able to group on NULL, we reserve place in group_buff
	    for the NULL flag just before the column.
	    The field data is after this flag.
	    The NULL flag is updated by 'end_update()' and 'end_write()'
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5173
	  */
5174 5175 5176 5177 5178
	  keyinfo->flags|= HA_NULL_ARE_EQUAL;	// def. that NULL == NULL
	  key_part_info->null_bit=field->null_bit;
	  key_part_info->null_offset= (uint) (field->null_ptr -
					      (uchar*) table->record[0]);
	  group->field->move_field((char*) ++group->buff);
5179
	  group_buff++;
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5180 5181 5182 5183 5184 5185 5186 5187 5188
	}
	else
	  group->field->move_field((char*) group_buff);
	group_buff+= key_part_info->length;
      }
      keyinfo->key_length+=  key_part_info->length;
    }
  }

5189
  if (distinct)
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5190
  {
5191 5192 5193 5194 5195 5196
    /*
      Create an unique key or an unique constraint over all columns
      that should be in the result.  In the temporary table, there are
      'param->hidden_field_count' extra columns, whose null bits are stored
      in the first 'hidden_null_pack_length' bytes of the row.
    */
5197 5198
    DBUG_PRINT("info",("hidden_field_count: %d", param->hidden_field_count));

5199
    null_pack_length-=hidden_null_pack_length;
5200
    keyinfo->key_parts= ((field_count-param->hidden_field_count)+
5201
			 test(null_pack_length));
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5202 5203
    set_if_smaller(table->max_rows, rows_limit);
    param->end_write_records= rows_limit;
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5204 5205 5206 5207 5208 5209 5210 5211 5212 5213 5214 5215
    table->distinct=1;
    table->keys=1;
    if (blob_count)
    {
      using_unique_constraint=1;
      table->uniques=1;
    }
    if (!(key_part_info= (KEY_PART_INFO*)
	  sql_calloc((keyinfo->key_parts)*sizeof(KEY_PART_INFO))))
      goto err;
    table->key_info=keyinfo;
    keyinfo->key_part=key_part_info;
5216
    keyinfo->flags=HA_NOSAME | HA_NULL_ARE_EQUAL;
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5217 5218
    keyinfo->key_length=(uint16) reclength;
    keyinfo->name=(char*) "tmp";
5219
    keyinfo->algorithm= HA_KEY_ALG_UNDEF;
5220
    if (null_pack_length)
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5221
    {
5222
      key_part_info->null_bit=0;
5223 5224
      key_part_info->offset=hidden_null_pack_length;
      key_part_info->length=null_pack_length;
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5225 5226 5227 5228 5229
      key_part_info->field=new Field_string((char*) table->record[0],
					    (uint32) key_part_info->length,
					    (uchar*) 0,
					    (uint) 0,
					    Field::NONE,
5230
					    NullS, table, &my_charset_bin);
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5231 5232 5233 5234
      key_part_info->key_type=FIELDFLAG_BINARY;
      key_part_info->type=    HA_KEYTYPE_BINARY;
      key_part_info++;
    }
5235
    /* Create a distinct key over the columns we are going to return */
5236 5237
    for (i=param->hidden_field_count, reg_field=table->field + i ;
	 i < field_count;
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5238 5239
	 i++, reg_field++, key_part_info++)
    {
5240
      key_part_info->null_bit=0;
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      key_part_info->field=    *reg_field;
      key_part_info->offset=   (*reg_field)->offset();
      key_part_info->length=   (uint16) (*reg_field)->pack_length();
      key_part_info->type=     (uint8) (*reg_field)->key_type();
      key_part_info->key_type =
	((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
	 (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT) ?
	0 : FIELDFLAG_BINARY;
    }
  }
5251
  if (thd->is_fatal_error)				// If end of memory
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    goto err;					 /* purecov: inspected */
  table->db_record_offset=1;
  if (table->db_type == DB_TYPE_MYISAM)
  {
    if (create_myisam_tmp_table(table,param,select_options))
      goto err;
  }
5259 5260
  /* Set table_name for easier debugging */
  table->table_name= base_name(tmpname);
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  if (!open_tmp_table(table))
    DBUG_RETURN(table);

 err:
5265 5266 5267 5268 5269
  /*
    Hack to ensure that free_blobs() doesn't fail if blob_field is not yet
    complete
  */
  *table->blob_field= 0;
5270
  free_tmp_table(thd,table);                    /* purecov: inspected */
5271
  bitmap_clear_bit(&temp_pool, temp_pool_slot);
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  DBUG_RETURN(NULL);				/* purecov: inspected */
}


static bool open_tmp_table(TABLE *table)
{
  int error;
  if ((error=table->file->ha_open(table->real_name,O_RDWR,HA_OPEN_TMP_TABLE)))
  {
    table->file->print_error(error,MYF(0)); /* purecov: inspected */
    table->db_stat=0;
    return(1);
  }
  (void) table->file->extra(HA_EXTRA_QUICK);		/* Faster */
  return(0);
}


static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
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				    ulong options)
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{
  int error;
  MI_KEYDEF keydef;
  MI_UNIQUEDEF uniquedef;
  KEY *keyinfo=param->keyinfo;

  DBUG_ENTER("create_myisam_tmp_table");
  if (table->keys)
  {						// Get keys for ni_create
    bool using_unique_constraint=0;
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    HA_KEYSEG *seg= (HA_KEYSEG*) sql_calloc(sizeof(*seg) *
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					    keyinfo->key_parts);
    if (!seg)
      goto err;

    if (keyinfo->key_length >= table->file->max_key_length() ||
	keyinfo->key_parts > table->file->max_key_parts() ||
	table->uniques)
    {
      /* Can't create a key; Make a unique constraint instead of a key */
      table->keys=0;
      table->uniques=1;
      using_unique_constraint=1;
      bzero((char*) &uniquedef,sizeof(uniquedef));
      uniquedef.keysegs=keyinfo->key_parts;
      uniquedef.seg=seg;
      uniquedef.null_are_equal=1;

      /* Create extra column for hash value */
      bzero((byte*) param->recinfo,sizeof(*param->recinfo));
      param->recinfo->type= FIELD_CHECK;
      param->recinfo->length=MI_UNIQUE_HASH_LENGTH;
      param->recinfo++;
      table->reclength+=MI_UNIQUE_HASH_LENGTH;
    }
    else
    {
      /* Create an unique key */
      bzero((char*) &keydef,sizeof(keydef));
      keydef.flag=HA_NOSAME | HA_BINARY_PACK_KEY | HA_PACK_KEY;
      keydef.keysegs=  keyinfo->key_parts;
      keydef.seg= seg;
    }
    for (uint i=0; i < keyinfo->key_parts ; i++,seg++)
    {
      Field *field=keyinfo->key_part[i].field;
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      seg->flag=     0;
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      seg->language= field->charset()->number;
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      seg->length=   keyinfo->key_part[i].length;
      seg->start=    keyinfo->key_part[i].offset;
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      if (field->flags & BLOB_FLAG)
      {
	seg->type=
	((keyinfo->key_part[i].key_type & FIELDFLAG_BINARY) ?
	 HA_KEYTYPE_VARBINARY : HA_KEYTYPE_VARTEXT);
	seg->bit_start=seg->length - table->blob_ptr_size;
	seg->flag= HA_BLOB_PART;
	seg->length=0;			// Whole blob in unique constraint
      }
      else
      {
	seg->type=
	  ((keyinfo->key_part[i].key_type & FIELDFLAG_BINARY) ?
	   HA_KEYTYPE_BINARY : HA_KEYTYPE_TEXT);
	if (!(field->flags & ZEROFILL_FLAG) &&
	    (field->type() == FIELD_TYPE_STRING ||
	     field->type() == FIELD_TYPE_VAR_STRING) &&
	    keyinfo->key_part[i].length > 4)
	  seg->flag|=HA_SPACE_PACK;
      }
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      if (!(field->flags & NOT_NULL_FLAG))
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      {
	seg->null_bit= field->null_bit;
	seg->null_pos= (uint) (field->null_ptr - (uchar*) table->record[0]);
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	/*
	  We are using a GROUP BY on something that contains NULL
	  In this case we have to tell MyISAM that two NULL should
	  on INSERT be compared as equal
	*/
	if (!using_unique_constraint)
	  keydef.flag|= HA_NULL_ARE_EQUAL;
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      }
    }
  }
  MI_CREATE_INFO create_info;
  bzero((char*) &create_info,sizeof(create_info));
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  if ((options & (OPTION_BIG_TABLES | SELECT_SMALL_RESULT)) ==
      OPTION_BIG_TABLES)
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    create_info.data_file_length= ~(ulonglong) 0;

  if ((error=mi_create(table->real_name,table->keys,&keydef,
		       (uint) (param->recinfo-param->start_recinfo),
		       param->start_recinfo,
		       table->uniques, &uniquedef,
		       &create_info,
		       HA_CREATE_TMP_TABLE)))
  {
    table->file->print_error(error,MYF(0));	/* purecov: inspected */
    table->db_stat=0;
    goto err;
  }
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  statistic_increment(created_tmp_disk_tables, &LOCK_status);
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  table->db_record_offset=1;
  DBUG_RETURN(0);
 err:
  DBUG_RETURN(1);
}


void
free_tmp_table(THD *thd, TABLE *entry)
{
  const char *save_proc_info;
  DBUG_ENTER("free_tmp_table");
  DBUG_PRINT("enter",("table: %s",entry->table_name));

  save_proc_info=thd->proc_info;
  thd->proc_info="removing tmp table";
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  free_blobs(entry);
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  if (entry->db_stat && entry->file)
  {
    (void) entry->file->close();
    delete entry->file;
  }
  if (!(test_flags & TEST_KEEP_TMP_TABLES) || entry->db_type == DB_TYPE_HEAP)
    (void) ha_delete_table(entry->db_type,entry->real_name);
  /* free blobs */
  for (Field **ptr=entry->field ; *ptr ; ptr++)
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    (*ptr)->free();
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  my_free((gptr) entry->record[0],MYF(0));
  free_io_cache(entry);
5424

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  bitmap_clear_bit(&temp_pool, entry->temp_pool_slot);
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  my_free((gptr) entry,MYF(0));
  thd->proc_info=save_proc_info;

  DBUG_VOID_RETURN;
}

/*
* If a HEAP table gets full, create a MyISAM table and copy all rows to this
*/

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bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
			     int error, bool ignore_last_dupp_key_error)
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{
  TABLE new_table;
  const char *save_proc_info;
  int write_err;
  DBUG_ENTER("create_myisam_from_heap");

  if (table->db_type != DB_TYPE_HEAP || error != HA_ERR_RECORD_FILE_FULL)
  {
    table->file->print_error(error,MYF(0));
    DBUG_RETURN(1);
  }
  new_table= *table;
  new_table.db_type=DB_TYPE_MYISAM;
  if (!(new_table.file=get_new_handler(&new_table,DB_TYPE_MYISAM)))
    DBUG_RETURN(1);				// End of memory

  save_proc_info=thd->proc_info;
  thd->proc_info="converting HEAP to MyISAM";

  if (create_myisam_tmp_table(&new_table,param,
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			      thd->lex->select_lex.options | thd->options))
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    goto err2;
  if (open_tmp_table(&new_table))
    goto err1;
  table->file->index_end();
  table->file->rnd_init();
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  if (table->no_rows)
  {
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    new_table.file->extra(HA_EXTRA_NO_ROWS);
    new_table.no_rows=1;
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  }

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  /* copy all old rows */
  while (!table->file->rnd_next(new_table.record[1]))
  {
    if ((write_err=new_table.file->write_row(new_table.record[1])))
      goto err;
  }
  /* copy row that filled HEAP table */
  if ((write_err=new_table.file->write_row(table->record[0])))
  {
    if (write_err != HA_ERR_FOUND_DUPP_KEY &&
	write_err != HA_ERR_FOUND_DUPP_UNIQUE || !ignore_last_dupp_key_error)
    goto err;
  }

  /* remove heap table and change to use myisam table */
  (void) table->file->rnd_end();
  (void) table->file->close();
  (void) table->file->delete_table(table->real_name);
  delete table->file;
  table->file=0;
  *table =new_table;
  table->file->change_table_ptr(table);
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  thd->proc_info= (!strcmp(save_proc_info,"Copying to tmp table") ?
		   "Copying to tmp table on disk" : save_proc_info);
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  DBUG_RETURN(0);

 err:
  DBUG_PRINT("error",("Got error: %d",write_err));
  table->file->print_error(error,MYF(0));	// Give table is full error
  (void) table->file->rnd_end();
  (void) new_table.file->close();
 err1:
  new_table.file->delete_table(new_table.real_name);
  delete new_table.file;
 err2:
  thd->proc_info=save_proc_info;
  DBUG_RETURN(1);
}


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/****************************************************************************
  Make a join of all tables and write it on socket or to table
  Return:  0 if ok
           1 if error is sent
          -1 if error should be sent
****************************************************************************/
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static int
do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
{
5521
  int error= 0;
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  JOIN_TAB *join_tab;
  int (*end_select)(JOIN *, struct st_join_table *,bool);
  DBUG_ENTER("do_select");

  join->procedure=procedure;
  /*
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    Tell the client how many fields there are in a row
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  */
  if (!table)
    join->result->send_fields(*fields,1);
  else
  {
    VOID(table->file->extra(HA_EXTRA_WRITE_CACHE));
    empty_record(table);
  }
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  join->tmp_table= table;			/* Save for easy recursion */
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  join->fields= fields;

  /* Set up select_end */
  if (table)
  {
    if (table->group && join->tmp_table_param.sum_func_count)
    {
      if (table->keys)
      {
5547
	DBUG_PRINT("info",("Using end_update"));
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	end_select=end_update;
	table->file->index_init(0);
      }
      else
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      {
	DBUG_PRINT("info",("Using end_unique_update"));
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	end_select=end_unique_update;
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      }
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    }
    else if (join->sort_and_group)
    {
      DBUG_PRINT("info",("Using end_write_group"));
      end_select=end_write_group;
    }
    else
    {
      DBUG_PRINT("info",("Using end_write"));
      end_select=end_write;
    }
  }
  else
  {
    if (join->sort_and_group || (join->procedure &&
				 join->procedure->flags & PROC_GROUP))
      end_select=end_send_group;
    else
      end_select=end_send;
  }
  join->join_tab[join->tables-1].next_select=end_select;

  join_tab=join->join_tab+join->const_tables;
  join->send_records=0;
  if (join->tables == join->const_tables)
  {
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    /*
      HAVING will be chcked after processing aggregate functions,
      But WHERE should checkd here (we alredy have read tables)
    */
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    if (!join->conds || join->conds->val_int())
5587
    {
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      if (!(error=(*end_select)(join,join_tab,0)) || error == -3)
	error=(*end_select)(join,join_tab,1);
5590
    }
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  }
  else
  {
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    error= sub_select(join,join_tab,0);
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    if (error >= 0)
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      error= sub_select(join,join_tab,1);
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    if (error == -3)
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      error= 0;					/* select_limit used */
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  }
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  if (error >= 0)
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  {
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    error=0;
    if (!table)					// If sending data to client
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    {
5606
      /*
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	The following will unlock all cursors if the command wasn't an
	update command
5609
      */
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      join->join_free(0);				// Unlock all cursors
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      if (join->result->send_eof())
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	error= 1;				// Don't send error
5613
    }
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    DBUG_PRINT("info",("%ld records output",join->send_records));
  }
  if (table)
  {
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    int tmp;
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    if ((tmp=table->file->extra(HA_EXTRA_NO_CACHE)))
    {
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      DBUG_PRINT("error",("extra(HA_EXTRA_NO_CACHE) failed"));
      my_errno= tmp;
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      error= -1;
    }
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    if ((tmp=table->file->index_end()))
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    {
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      DBUG_PRINT("error",("index_end() failed"));
      my_errno= tmp;
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      error= -1;
    }
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    if (error == -1)
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      table->file->print_error(my_errno,MYF(0));
  }
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#ifndef DBUG_OFF
  if (error)
  {
    DBUG_PRINT("error",("Error: do_select() failed"));
  }
#endif
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  DBUG_RETURN(error || join->thd->net.report_error);
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}


static int
sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
  int error;

  if (end_of_records)
  {
    if ((error=flush_cached_records(join,join_tab,FALSE)) < 0)
      return error; /* purecov: inspected */
    return sub_select(join,join_tab,end_of_records);
  }
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  if (join->thd->killed)		// If aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
    return -2;				 /* purecov: inspected */
  }
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  if (join_tab->use_quick != 2 || test_if_quick_select(join_tab) <= 0)
  {
    if (!store_record_in_cache(&join_tab->cache))
      return 0;					// There is more room in cache
    return flush_cached_records(join,join_tab,FALSE);
  }
  if ((error=flush_cached_records(join,join_tab,TRUE)) < 0)
    return error; /* purecov: inspected */
  return sub_select(join,join_tab,end_of_records); /* Use ordinary select */
}


static int
sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{

  join_tab->table->null_row=0;
  if (end_of_records)
    return (*join_tab->next_select)(join,join_tab+1,end_of_records);

  /* Cache variables for faster loop */
  int error;
  bool found=0;
  COND *on_expr=join_tab->on_expr, *select_cond=join_tab->select_cond;
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  my_bool *report_error= &(join->thd->net.report_error);
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  if (!(error=(*join_tab->read_first_record)(join_tab)))
  {
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    bool not_exists_optimize= join_tab->table->reginfo.not_exists_optimize;
    bool not_used_in_distinct=join_tab->not_used_in_distinct;
    ha_rows found_records=join->found_records;
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    READ_RECORD *info= &join_tab->read_record;

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    join->thd->row_count= 0;
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    do
    {
      if (join->thd->killed)			// Aborted by user
      {
	my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
	return -2;				/* purecov: inspected */
      }
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      join->examined_rows++;
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      join->thd->row_count++;
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      if (!on_expr || on_expr->val_int())
      {
	found=1;
	if (not_exists_optimize)
	  break;			// Searching after not null columns
	if (!select_cond || select_cond->val_int())
	{
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	  if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
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	    return error;
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	  /*
	    Test if this was a SELECT DISTINCT query on a table that
	    was not in the field list;  In this case we can abort if
	    we found a row, as no new rows can be added to the result.
	  */
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	  if (not_used_in_distinct && found_records != join->found_records)
	    return 0;
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	}
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	else
	  info->file->unlock_row();
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      }
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    } while (!(error=info->read_record(info)) && !(*report_error));
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  }
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  if (error > 0 || (*report_error))				// Fatal error
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    return -1;

  if (!found && on_expr)
  {						// OUTER JOIN
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    restore_record(join_tab->table,default_values);		// Make empty record
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    mark_as_null_row(join_tab->table);		// For group by without error
    if (!select_cond || select_cond->val_int())
    {
5734
      if ((error=(*join_tab->next_select)(join,join_tab+1,0)) < 0)
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	return error;				/* purecov: inspected */
    }
  }
  return 0;
}


static int
flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skipp_last)
{
  int error;
  READ_RECORD *info;

  if (!join_tab->cache.records)
    return 0;				/* Nothing to do */
  if (skipp_last)
    (void) store_record_in_cache(&join_tab->cache); // Must save this for later
  if (join_tab->use_quick == 2)
  {
    if (join_tab->select->quick)
    {					/* Used quick select last. reset it */
      delete join_tab->select->quick;
      join_tab->select->quick=0;
    }
  }
 /* read through all records */
  if ((error=join_init_read_record(join_tab)))
  {
    reset_cache(&join_tab->cache);
    join_tab->cache.records=0; join_tab->cache.ptr_record= (uint) ~0;
    return -error;			/* No records or error */
  }

  for (JOIN_TAB *tmp=join->join_tab; tmp != join_tab ; tmp++)
  {
    tmp->status=tmp->table->status;
    tmp->table->status=0;
  }

  info= &join_tab->read_record;
  do
  {
    if (join->thd->killed)
    {
      my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
      return -2;				// Aborted by user /* purecov: inspected */
    }
    SQL_SELECT *select=join_tab->select;
    if (!error && (!join_tab->cache.select ||
		   !join_tab->cache.select->skipp_record()))
    {
      uint i;
      reset_cache(&join_tab->cache);
      for (i=(join_tab->cache.records- (skipp_last ? 1 : 0)) ; i-- > 0 ;)
      {
	read_cached_record(join_tab);
	if (!select || !select->skipp_record())
	  if ((error=(join_tab->next_select)(join,join_tab+1,0)) < 0)
	    return error; /* purecov: inspected */
      }
    }
  } while (!(error=info->read_record(info)));

  if (skipp_last)
    read_cached_record(join_tab);		// Restore current record
  reset_cache(&join_tab->cache);
  join_tab->cache.records=0; join_tab->cache.ptr_record= (uint) ~0;
  if (error > 0)				// Fatal error
    return -1;					/* purecov: inspected */
  for (JOIN_TAB *tmp2=join->join_tab; tmp2 != join_tab ; tmp2++)
    tmp2->table->status=tmp2->status;
  return 0;
}


/*****************************************************************************
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  The different ways to read a record
  Returns -1 if row was not found, 0 if row was found and 1 on errors
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*****************************************************************************/
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/* Help function when we get some an error from the table handler */

5817
int report_error(TABLE *table, int error)
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{
  if (error == HA_ERR_END_OF_FILE || error == HA_ERR_KEY_NOT_FOUND)
  {
    table->status= STATUS_GARBAGE;
    return -1;					// key not found; ok
  }
  /*
    Locking reads can legally return also these errors, do not
    print them to the .err log
  */
  if (error != HA_ERR_LOCK_DEADLOCK && error != HA_ERR_LOCK_WAIT_TIMEOUT)
    sql_print_error("Got error %d when reading table '%s'",
		    error, table->path);
  table->file->print_error(error,MYF(0));
  return 1;
}


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int safe_index_read(JOIN_TAB *tab)
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{
  int error;
  TABLE *table= tab->table;
  if ((error=table->file->index_read(table->record[0],
				     tab->ref.key_buff,
				     tab->ref.key_length, HA_READ_KEY_EXACT)))
    return report_error(table, error);
  return 0;
}


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static int
5849
join_read_const_table(JOIN_TAB *tab, POSITION *pos)
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{
  int error;
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  DBUG_ENTER("join_read_const_table");
  TABLE *table=tab->table;
  table->const_table=1;
  table->null_row=0;
  table->status=STATUS_NO_RECORD;
  
  if (tab->type == JT_SYSTEM)
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  {
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    if ((error=join_read_system(tab)))
    {						// Info for DESCRIBE
      tab->info="const row not found";
      /* Mark for EXPLAIN that the row was not found */
      pos->records_read=0.0;
      if (!table->outer_join || error > 0)
	DBUG_RETURN(error);
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    }
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  }
  else
  {
    if ((error=join_read_const(tab)))
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    {
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      tab->info="unique row not found";
      /* Mark for EXPLAIN that the row was not found */
      pos->records_read=0.0;
      if (!table->outer_join || error > 0)
	DBUG_RETURN(error);
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    }
  }
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  if (tab->on_expr && !table->null_row)
  {
    if ((table->null_row= test(tab->on_expr->val_int() == 0)))
      empty_record(table);
    }
  if (!table->null_row)
    table->maybe_null=0;
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  DBUG_RETURN(0);
}


static int
join_read_system(JOIN_TAB *tab)
{
  TABLE *table= tab->table;
  int error;
  if (table->status & STATUS_GARBAGE)		// If first read
  {
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    if ((error=table->file->read_first_row(table->record[0],
					   table->primary_key)))
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    {
      if (error != HA_ERR_END_OF_FILE)
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	return report_error(table, error);
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      table->null_row=1;			// This is ok.
      empty_record(table);			// Make empty record
      return -1;
    }
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    store_record(table,record[1]);
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  }
  else if (!table->status)			// Only happens with left join
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    restore_record(table,record[1]);			// restore old record
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  table->null_row=0;
  return table->status ? -1 : 0;
}


static int
join_read_const(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;
  if (table->status & STATUS_GARBAGE)		// If first read
  {
    if (cp_buffer_from_ref(&tab->ref))
      error=HA_ERR_KEY_NOT_FOUND;
    else
    {
      error=table->file->index_read_idx(table->record[0],tab->ref.key,
					(byte*) tab->ref.key_buff,
					tab->ref.key_length,HA_READ_KEY_EXACT);
    }
    if (error)
    {
      table->null_row=1;
      empty_record(table);
      if (error != HA_ERR_KEY_NOT_FOUND)
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	return report_error(table, error);
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      return -1;
    }
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    store_record(table,record[1]);
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  }
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  else if (!(table->status & ~STATUS_NULL_ROW))	// Only happens with left join
  {
    table->status=0;
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    restore_record(table,record[1]);			// restore old record
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  }
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  table->null_row=0;
  return table->status ? -1 : 0;
}


static int
join_read_key(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;

  if (cmp_buffer_with_ref(tab) ||
5958
      (table->status & (STATUS_GARBAGE | STATUS_NO_PARENT | STATUS_NULL_ROW)))
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  {
    if (tab->ref.key_err)
    {
      table->status=STATUS_NOT_FOUND;
      return -1;
    }
    error=table->file->index_read(table->record[0],
				  tab->ref.key_buff,
				  tab->ref.key_length,HA_READ_KEY_EXACT);
    if (error && error != HA_ERR_KEY_NOT_FOUND)
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      return report_error(table, error);
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  }
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  table->null_row=0;
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  return table->status ? -1 : 0;
}


static int
join_read_always_key(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;

  if (cp_buffer_from_ref(&tab->ref))
    return -1;
  if ((error=table->file->index_read(table->record[0],
				     tab->ref.key_buff,
				     tab->ref.key_length,HA_READ_KEY_EXACT)))
  {
    if (error != HA_ERR_KEY_NOT_FOUND)
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      return report_error(table, error);
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    return -1; /* purecov: inspected */
  }
  return 0;
}

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/*
  This function is used when optimizing away ORDER BY in 
  SELECT * FROM t1 WHERE a=1 ORDER BY a DESC,b DESC
*/
  
static int
join_read_last_key(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;

  if (cp_buffer_from_ref(&tab->ref))
    return -1;
  if ((error=table->file->index_read_last(table->record[0],
					  tab->ref.key_buff,
					  tab->ref.key_length)))
  {
    if (error != HA_ERR_KEY_NOT_FOUND)
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      return report_error(table, error);
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    return -1; /* purecov: inspected */
  }
  return 0;
}

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	/* ARGSUSED */
static int
join_no_more_records(READ_RECORD *info __attribute__((unused)))
{
  return -1;
}


static int
6030
join_read_next_same(READ_RECORD *info)
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{
  int error;
  TABLE *table= info->table;
  JOIN_TAB *tab=table->reginfo.join_tab;

  if ((error=table->file->index_next_same(table->record[0],
					  tab->ref.key_buff,
					  tab->ref.key_length)))
  {
    if (error != HA_ERR_END_OF_FILE)
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      return report_error(table, error);
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    table->status= STATUS_GARBAGE;
    return -1;
  }
  return 0;
}

6048

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static int
join_read_prev_same(READ_RECORD *info)
{
  int error;
  TABLE *table= info->table;
  JOIN_TAB *tab=table->reginfo.join_tab;

  if ((error=table->file->index_prev(table->record[0])))
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    return report_error(table, error);
  if (key_cmp(table, tab->ref.key_buff, tab->ref.key,
	      tab->ref.key_length))
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  {
    table->status=STATUS_NOT_FOUND;
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    error= -1;
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  }
  return error;
}

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static int
join_init_quick_read_record(JOIN_TAB *tab)
{
  if (test_if_quick_select(tab) == -1)
    return -1;					/* No possible records */
  return join_init_read_record(tab);
}


static int
test_if_quick_select(JOIN_TAB *tab)
{
  delete tab->select->quick;
  tab->select->quick=0;
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  return tab->select->test_quick_select(tab->join->thd, tab->keys,
					(table_map) 0, HA_POS_ERROR);
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}


static int
join_init_read_record(JOIN_TAB *tab)
{
  if (tab->select && tab->select->quick)
    tab->select->quick->reset();
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  init_read_record(&tab->read_record, tab->join->thd, tab->table,
		   tab->select,1,1);
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  return (*tab->read_record.read_record)(&tab->read_record);
}

6097

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static int
6099
join_read_first(JOIN_TAB *tab)
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{
  int error;
  TABLE *table=tab->table;
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  if (!table->key_read && table->used_keys.is_set(tab->index) &&
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      !table->no_keyread)
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  {
    table->key_read=1;
    table->file->extra(HA_EXTRA_KEYREAD);
  }
  tab->table->status=0;
6110
  tab->read_record.read_record=join_read_next;
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  tab->read_record.table=table;
  tab->read_record.file=table->file;
  tab->read_record.index=tab->index;
  tab->read_record.record=table->record[0];
6115
  if ((error=tab->table->file->index_first(tab->table->record[0])))
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  {
    if (error != HA_ERR_KEY_NOT_FOUND && error != HA_ERR_END_OF_FILE)
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      report_error(table, error);
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    return -1;
  }
  return 0;
}

6124

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static int
6126
join_read_next(READ_RECORD *info)
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{
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  int error;
  if ((error=info->file->index_next(info->record)))
    return report_error(info->table, error);
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  return 0;
}

6134

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static int
6136
join_read_last(JOIN_TAB *tab)
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{
  TABLE *table=tab->table;
  int error;
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  if (!table->key_read && table->used_keys.is_set(tab->index) &&
6141
      !table->no_keyread)
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  {
    table->key_read=1;
    table->file->extra(HA_EXTRA_KEYREAD);
  }
  tab->table->status=0;
6147
  tab->read_record.read_record=join_read_prev;
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  tab->read_record.table=table;
  tab->read_record.file=table->file;
  tab->read_record.index=tab->index;
  tab->read_record.record=table->record[0];
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  if ((error= tab->table->file->index_last(tab->table->record[0])))
    return report_error(table, error);
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  return 0;
}

6157

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static int
6159
join_read_prev(READ_RECORD *info)
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{
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  int error;
  if ((error= info->file->index_prev(info->record)))
    return report_error(info->table, error);
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  return 0;
}

6167

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static int
join_ft_read_first(JOIN_TAB *tab)
{
  int error;
  TABLE *table= tab->table;

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#if NOT_USED_YET
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  if (cp_buffer_from_ref(&tab->ref))       // as ft-key doesn't use store_key's
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    return -1;                             // see also FT_SELECT::init()
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#endif
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  table->file->ft_init();
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  if ((error= table->file->ft_read(table->record[0])))
    return report_error(table, error);
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  return 0;
}

static int
join_ft_read_next(READ_RECORD *info)
{
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  int error;
  if ((error= info->file->ft_read(info->table->record[0])))
    return report_error(info->table, error);
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  return 0;
}


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/*
  Reading of key with key reference and one part that may be NULL
*/

static int
join_read_always_key_or_null(JOIN_TAB *tab)
{
  int res;

  /* First read according to key which is NOT NULL */
  *tab->null_ref_key=0;
  if ((res= join_read_always_key(tab)) >= 0)
    return res;

  /* Then read key with null value */
  *tab->null_ref_key= 1;
  return safe_index_read(tab);
}


static int
join_read_next_same_or_null(READ_RECORD *info)
{
  int error;
  if ((error= join_read_next_same(info)) >= 0)
    return error;
  JOIN_TAB *tab= info->table->reginfo.join_tab;

  /* Test if we have already done a read after null key */
  if (*tab->null_ref_key)
    return -1;					// All keys read
  *tab->null_ref_key= 1;			// Read null key
  return safe_index_read(tab);
}


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/*****************************************************************************
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  The different end of select functions
  These functions returns < 0 when end is reached, 0 on ok and > 0 if a
  fatal error (like table corruption) was detected
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*****************************************************************************/

6237
/* ARGSUSED */
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static int
end_send(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	 bool end_of_records)
{
  DBUG_ENTER("end_send");
  if (!end_of_records)
  {
    int error;
6246
    if (join->having && join->having->val_int() == 0)
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      DBUG_RETURN(0);				// Didn't match having
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    error=0;
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    if (join->procedure)
      error=join->procedure->send_row(*join->fields);
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    else if (join->do_send_rows)
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      error=join->result->send_data(*join->fields);
    if (error)
      DBUG_RETURN(-1); /* purecov: inspected */
6255
    if (++join->send_records >= join->unit->select_limit_cnt &&
6256
	join->do_send_rows)
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    {
      if (join->select_options & OPTION_FOUND_ROWS)
      {
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	JOIN_TAB *jt=join->join_tab;
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	if ((join->tables == 1) && !join->tmp_table && !join->sort_and_group
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	    && !join->send_group_parts && !join->having && !jt->select_cond &&
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	    !(jt->select && jt->select->quick) &&
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	    !(jt->table->file->table_flags() & HA_NOT_EXACT_COUNT))
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	{
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	  /* Join over all rows in table;  Return number of found rows */
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	  TABLE *table=jt->table;

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	  join->select_options ^= OPTION_FOUND_ROWS;
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	  if (table->sort.record_pointers ||
	      (table->sort.io_cache && my_b_inited(table->sort.io_cache)))
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	  {
	    /* Using filesort */
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	    join->send_records= table->sort.found_records;
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	  }
	  else
	  {
	    table->file->info(HA_STATUS_VARIABLE);
	    join->send_records = table->file->records;
	  }
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	}
	else 
	{
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	  join->do_send_rows= 0;
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	  if (join->unit->fake_select_lex)
	    join->unit->fake_select_lex->select_limit= HA_POS_ERROR;
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	  DBUG_RETURN(0);
	}
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      }
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      DBUG_RETURN(-3);				// Abort nicely
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    }
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  }
  else
  {
    if (join->procedure && join->procedure->end_of_records())
      DBUG_RETURN(-1);
  }
  DBUG_RETURN(0);
}


	/* ARGSUSED */
static int
end_send_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	       bool end_of_records)
{
  int idx= -1;
  DBUG_ENTER("end_send_group");

  if (!join->first_record || end_of_records ||
      (idx=test_if_group_changed(join->group_fields)) >= 0)
  {
    if (join->first_record || (end_of_records && !join->group))
    {
      if (join->procedure)
	join->procedure->end_group();
      if (idx < (int) join->send_group_parts)
      {
6319
	int error=0;
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	if (join->procedure)
	{
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	  if (join->having && join->having->val_int() == 0)
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	    error= -1;				// Didn't satisfy having
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 	  else
	  {
	    if (join->do_send_rows)
	      error=join->procedure->send_row(*join->fields) ? 1 : 0;
	    join->send_records++;
	  }
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	  if (end_of_records && join->procedure->end_of_records())
	    error= 1;				// Fatal error
	}
	else
	{
	  if (!join->first_record)
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	  {
	    /* No matching rows for group function */
6338
	    join->clear();
6339
	  }
6340
	  if (join->having && join->having->val_int() == 0)
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	    error= -1;				// Didn't satisfy having
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	  else
	  {
	    if (join->do_send_rows)
	      error=join->result->send_data(*join->fields) ? 1 : 0;
	    join->send_records++;
	  }
	  if (join->rollup.state != ROLLUP::STATE_NONE && error <= 0)
	  {
	    if (join->rollup_send_data((uint) (idx+1)))
	      error= 1;
	  }
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	}
	if (error > 0)
	  DBUG_RETURN(-1);			/* purecov: inspected */
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	if (end_of_records)
	  DBUG_RETURN(0);
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	if (join->send_records >= join->unit->select_limit_cnt &&
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	    join->do_send_rows)
	{
	  if (!(join->select_options & OPTION_FOUND_ROWS))
	    DBUG_RETURN(-3);				// Abort nicely
	  join->do_send_rows=0;
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	  join->unit->select_limit_cnt = HA_POS_ERROR;
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        }
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      }
    }
    else
    {
      if (end_of_records)
	DBUG_RETURN(0);
      join->first_record=1;
      VOID(test_if_group_changed(join->group_fields));
    }
    if (idx < (int) join->send_group_parts)
    {
      copy_fields(&join->tmp_table_param);
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      if (init_sum_functions(join->sum_funcs, join->sum_funcs_end[idx+1]))
	DBUG_RETURN(-1);
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      if (join->procedure)
	join->procedure->add();
      DBUG_RETURN(0);
    }
  }
  if (update_sum_func(join->sum_funcs))
    DBUG_RETURN(-1);
  if (join->procedure)
    join->procedure->add();
  DBUG_RETURN(0);
}


	/* ARGSUSED */
static int
end_write(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	  bool end_of_records)
{
  TABLE *table=join->tmp_table;
  int error;
  DBUG_ENTER("end_write");

  if (join->thd->killed)			// Aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }
  if (!end_of_records)
  {
    copy_fields(&join->tmp_table_param);
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    copy_funcs(join->tmp_table_param.items_to_copy);
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#ifdef TO_BE_DELETED
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    if (!table->uniques)			// If not unique handling
    {
      /* Copy null values from group to row */
      ORDER   *group;
      for (group=table->group ; group ; group=group->next)
      {
	Item *item= *group->item;
	if (item->maybe_null)
	{
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	  Field *field=item->get_tmp_table_field();
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	  field->ptr[-1]= (byte) (field->is_null() ? 1 : 0);
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	}
      }
    }
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#endif
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    if (!join->having || join->having->val_int())
    {
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      join->found_records++;
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      if ((error=table->file->write_row(table->record[0])))
      {
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	if (error == HA_ERR_FOUND_DUPP_KEY ||
	    error == HA_ERR_FOUND_DUPP_UNIQUE)
	  goto end;
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	if (create_myisam_from_heap(join->thd, table, &join->tmp_table_param,
				    error,1))
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	  DBUG_RETURN(-1);			// Not a table_is_full error
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	table->uniques=0;			// To ensure rows are the same
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      }
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      if (++join->send_records >= join->tmp_table_param.end_write_records &&
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	  join->do_send_rows)
      {
	if (!(join->select_options & OPTION_FOUND_ROWS))
	  DBUG_RETURN(-3);
	join->do_send_rows=0;
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	join->unit->select_limit_cnt = HA_POS_ERROR;
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	DBUG_RETURN(0);
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      }
    }
  }
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end:
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  DBUG_RETURN(0);
}

/* Group by searching after group record and updating it if possible */
/* ARGSUSED */

static int
end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
	   bool end_of_records)
{
  TABLE *table=join->tmp_table;
  ORDER   *group;
  int	  error;
  DBUG_ENTER("end_update");

  if (end_of_records)
    DBUG_RETURN(0);
  if (join->thd->killed)			// Aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }

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  join->found_records++;
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  copy_fields(&join->tmp_table_param);		// Groups are copied twice.
  /* Make a key of group index */
  for (group=table->group ; group ; group=group->next)
  {
    Item *item= *group->item;
    item->save_org_in_field(group->field);
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#ifdef EMBEDDED_LIBRARY
    join->thd->net.last_errno= 0;
#endif
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    /* Store in the used key if the field was 0 */
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    if (item->maybe_null)
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      group->buff[-1]=item->null_value ? 1 : 0;
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  }
  // table->file->index_init(0);
  if (!table->file->index_read(table->record[1],
			       join->tmp_table_param.group_buff,0,
			       HA_READ_KEY_EXACT))
  {						/* Update old record */
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    restore_record(table,record[1]);
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    update_tmptable_sum_func(join->sum_funcs,table);
    if ((error=table->file->update_row(table->record[1],
				       table->record[0])))
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
    DBUG_RETURN(0);
  }

  /* The null bits are already set */
  KEY_PART_INFO *key_part;
  for (group=table->group,key_part=table->key_info[0].key_part;
       group ;
       group=group->next,key_part++)
    memcpy(table->record[0]+key_part->offset, group->buff, key_part->length);

  init_tmptable_sum_functions(join->sum_funcs);
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  copy_funcs(join->tmp_table_param.items_to_copy);
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  if ((error=table->file->write_row(table->record[0])))
  {
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    if (create_myisam_from_heap(join->thd, table, &join->tmp_table_param,
				error, 0))
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      DBUG_RETURN(-1);				// Not a table_is_full error
    /* Change method to update rows */
    table->file->index_init(0);
    join->join_tab[join->tables-1].next_select=end_unique_update;
  }
  join->send_records++;
  DBUG_RETURN(0);
}

/* Like end_update, but this is done with unique constraints instead of keys */

static int
end_unique_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
		  bool end_of_records)
{
  TABLE *table=join->tmp_table;
  int	  error;
  DBUG_ENTER("end_unique_update");

  if (end_of_records)
    DBUG_RETURN(0);
  if (join->thd->killed)			// Aborted by user
  {
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }

  init_tmptable_sum_functions(join->sum_funcs);
  copy_fields(&join->tmp_table_param);		// Groups are copied twice.
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  copy_funcs(join->tmp_table_param.items_to_copy);
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  if (!(error=table->file->write_row(table->record[0])))
    join->send_records++;			// New group
  else
  {
    if ((int) table->file->get_dup_key(error) < 0)
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
    if (table->file->rnd_pos(table->record[1],table->file->dupp_ref))
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
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    restore_record(table,record[1]);
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    update_tmptable_sum_func(join->sum_funcs,table);
    if ((error=table->file->update_row(table->record[1],
				       table->record[0])))
    {
      table->file->print_error(error,MYF(0));	/* purecov: inspected */
      DBUG_RETURN(-1);				/* purecov: inspected */
    }
  }
  DBUG_RETURN(0);
}


	/* ARGSUSED */
static int
end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
		bool end_of_records)
{
  TABLE *table=join->tmp_table;
  int	  error;
  int	  idx= -1;
  DBUG_ENTER("end_write_group");

  if (join->thd->killed)
  {						// Aborted by user
    my_error(ER_SERVER_SHUTDOWN,MYF(0));	/* purecov: inspected */
    DBUG_RETURN(-2);				/* purecov: inspected */
  }
  if (!join->first_record || end_of_records ||
      (idx=test_if_group_changed(join->group_fields)) >= 0)
  {
    if (join->first_record || (end_of_records && !join->group))
    {
      if (join->procedure)
	join->procedure->end_group();
      if (idx < (int) join->send_group_parts)
      {
	if (!join->first_record)
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	{
	  /* No matching rows for group function */
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	  join->clear();
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	}
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	copy_sum_funcs(join->sum_funcs);
	if (!join->having || join->having->val_int())
	{
	  if ((error=table->file->write_row(table->record[0])))
	  {
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	    if (create_myisam_from_heap(join->thd, table,
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					&join->tmp_table_param,
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					error, 0))
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	      DBUG_RETURN(-1);			// Not a table_is_full error
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	  }
	  else
	    join->send_records++;
	}
	if (end_of_records)
	  DBUG_RETURN(0);
      }
    }
    else
    {
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      if (end_of_records)
	DBUG_RETURN(0);
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      join->first_record=1;
      VOID(test_if_group_changed(join->group_fields));
    }
    if (idx < (int) join->send_group_parts)
    {
      copy_fields(&join->tmp_table_param);
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      copy_funcs(join->tmp_table_param.items_to_copy);
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      if (init_sum_functions(join->sum_funcs, join->sum_funcs_end[idx+1]))
	DBUG_RETURN(-1);
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      if (join->procedure)
	join->procedure->add();
      DBUG_RETURN(0);
    }
  }
  if (update_sum_func(join->sum_funcs))
    DBUG_RETURN(-1);
  if (join->procedure)
    join->procedure->add();
  DBUG_RETURN(0);
}


/*****************************************************************************
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  Remove calculation with tables that aren't yet read. Remove also tests
  against fields that are read through key where the table is not a
  outer join table.
  We can't remove tests that are made against columns which are stored
  in sorted order.
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*****************************************************************************/

/* Return 1 if right_item is used removable reference key on left_item */

static bool test_if_ref(Item_field *left_item,Item *right_item)
{
  Field *field=left_item->field;
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  // No need to change const test. We also have to keep tests on LEFT JOIN
  if (!field->table->const_table && !field->table->maybe_null)
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  {
    Item *ref_item=part_of_refkey(field->table,field);
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    if (ref_item && ref_item->eq(right_item,1))
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    {
      if (right_item->type() == Item::FIELD_ITEM)
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	return (field->eq_def(((Item_field *) right_item)->field));
      if (right_item->const_item() && !(right_item->is_null()))
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      {
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	/*
	  We can remove binary fields and numerical fields except float,
	  as float comparison isn't 100 % secure
	*/
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	if (field->binary() &&
	    (field->type() != FIELD_TYPE_FLOAT || field->decimals() == 0))
	{
	  return !store_val_in_field(field,right_item);
	}
      }
    }
  }
  return 0;					// keep test
}


static COND *
make_cond_for_table(COND *cond,table_map tables,table_map used_table)
{
  if (used_table && !(cond->used_tables() & used_table))
    return (COND*) 0;				// Already checked
  if (cond->type() == Item::COND_ITEM)
  {
    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
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      /* Create new top level AND item */
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      Item_cond_and *new_cond=new Item_cond_and;
      if (!new_cond)
	return (COND*) 0;			// OOM /* purecov: inspected */
      List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
      Item *item;
      while ((item=li++))
      {
	Item *fix=make_cond_for_table(item,tables,used_table);
	if (fix)
	  new_cond->argument_list()->push_back(fix);
      }
      switch (new_cond->argument_list()->elements) {
      case 0:
	return (COND*) 0;			// Always true
      case 1:
	return new_cond->argument_list()->head();
      default:
	new_cond->used_tables_cache=((Item_cond*) cond)->used_tables_cache &
	  tables;
	return new_cond;
      }
    }
    else
    {						// Or list
      Item_cond_or *new_cond=new Item_cond_or;
      if (!new_cond)
	return (COND*) 0;			// OOM /* purecov: inspected */
      List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
      Item *item;
      while ((item=li++))
      {
	Item *fix=make_cond_for_table(item,tables,0L);
	if (!fix)
	  return (COND*) 0;			// Always true
	new_cond->argument_list()->push_back(fix);
      }
      new_cond->used_tables_cache=((Item_cond_or*) cond)->used_tables_cache;
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      new_cond->top_level_item();
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      return new_cond;
    }
  }

  /*
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    Because the following test takes a while and it can be done
    table_count times, we mark each item that we have examined with the result
    of the test
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  */

  if (cond->marker == 3 || (cond->used_tables() & ~tables))
    return (COND*) 0;				// Can't check this yet
  if (cond->marker == 2 || cond->eq_cmp_result() == Item::COND_OK)
    return cond;				// Not boolean op

  if (((Item_func*) cond)->functype() == Item_func::EQ_FUNC)
  {
    Item *left_item=	((Item_func*) cond)->arguments()[0];
    Item *right_item= ((Item_func*) cond)->arguments()[1];
    if (left_item->type() == Item::FIELD_ITEM &&
	test_if_ref((Item_field*) left_item,right_item))
    {
      cond->marker=3;			// Checked when read
      return (COND*) 0;
    }
    if (right_item->type() == Item::FIELD_ITEM &&
	test_if_ref((Item_field*) right_item,left_item))
    {
      cond->marker=3;			// Checked when read
      return (COND*) 0;
    }
  }
  cond->marker=2;
  return cond;
}

static Item *
part_of_refkey(TABLE *table,Field *field)
{
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  if (!table->reginfo.join_tab)
    return (Item*) 0;             // field from outer non-select (UPDATE,...)

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  uint ref_parts=table->reginfo.join_tab->ref.key_parts;
  if (ref_parts)
  {
    KEY_PART_INFO *key_part=
      table->key_info[table->reginfo.join_tab->ref.key].key_part;

    for (uint part=0 ; part < ref_parts ; part++,key_part++)
      if (field->eq(key_part->field) &&
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	  !(key_part->key_part_flag & HA_PART_KEY_SEG))
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	return table->reginfo.join_tab->ref.items[part];
  }
  return (Item*) 0;
}


/*****************************************************************************
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  Test if one can use the key to resolve ORDER BY
  Returns: 1 if key is ok.
	   0 if key can't be used
	  -1 if reverse key can be used
          used_key_parts is set to key parts used if length != 0
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*****************************************************************************/

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static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
				uint *used_key_parts)
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{
  KEY_PART_INFO *key_part,*key_part_end;
  key_part=table->key_info[idx].key_part;
  key_part_end=key_part+table->key_info[idx].key_parts;
  key_part_map const_key_parts=table->const_key_parts[idx];
  int reverse=0;

  for (; order ; order=order->next, const_key_parts>>=1)
  {
    Field *field=((Item_field*) (*order->item))->field;
    int flag;

    /*
      Skip key parts that are constants in the WHERE clause.
      These are already skipped in the ORDER BY by const_expression_in_where()
    */
    while (const_key_parts & 1)
    {
      key_part++; const_key_parts>>=1;
    }
    if (key_part == key_part_end || key_part->field != field)
      return 0;

    /* set flag to 1 if we can use read-next on key, else to -1 */
    flag=(order->asc == !(key_part->key_part_flag & HA_REVERSE_SORT))
      ? 1 : -1;
    if (reverse && flag != reverse)
      return 0;
    reverse=flag;				// Remember if reverse
    key_part++;
  }
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  *used_key_parts= (uint) (key_part - table->key_info[idx].key_part);
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  return reverse;
}

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static uint find_shortest_key(TABLE *table, const key_map *usable_keys)
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{
  uint min_length= (uint) ~0;
  uint best= MAX_KEY;
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  if (!usable_keys->is_clear_all())
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  {
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    for (uint nr=0; nr < table->keys ; nr++)
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    {
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      if (usable_keys->is_set(nr))
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      {
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        if (table->key_info[nr].key_length < min_length)
        {
          min_length=table->key_info[nr].key_length;
          best=nr;
        }
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      }
    }
  }
  return best;
}

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/*
  SYNOPSIS
    is_subkey()
    key_part		- first key parts
    ref_key_part	- second key parts
    ref_key_part_end	- last+1 part of the second key
  DESCRIPTION
    Test if a second key is the subkey of the first one.
  NOTE
    Second key MUST be shorter than the first one.
  RETURN
    1	- is the subkey
    0	- otherwise
*/

inline bool 
is_subkey(KEY_PART_INFO *key_part, KEY_PART_INFO *ref_key_part,
	  KEY_PART_INFO *ref_key_part_end)
{
  for (; ref_key_part < ref_key_part_end; key_part++, ref_key_part++)
    if (!key_part->field->eq(ref_key_part->field))
      return 0;
  return 1;
}

/*
  SYNOPSIS
    test_if_subkey()
    ref		- number of key, used for WHERE clause
    usable_keys - keys for testing
  DESCRIPTION
    Test if we can use one of the 'usable_keys' instead of 'ref' key.
  RETURN
    MAX_KEY			- if we can't use other key
    the number of found key	- otherwise
*/

static uint
6897
test_if_subkey(ORDER *order, TABLE *table, uint ref, uint ref_key_parts,
6898
	       const key_map& usable_keys)
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{
  uint nr;
  uint min_length= (uint) ~0;
  uint best= MAX_KEY;
  uint not_used;
  KEY_PART_INFO *ref_key_part= table->key_info[ref].key_part;
  KEY_PART_INFO *ref_key_part_end= ref_key_part + ref_key_parts;
6906

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  for (nr= 0 ; nr < table->keys ; nr++)
6908
  {
6909
    if (usable_keys.is_set(nr) &&
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	table->key_info[nr].key_length < min_length &&
	table->key_info[nr].key_parts >= ref_key_parts &&
	is_subkey(table->key_info[nr].key_part, ref_key_part,
		  ref_key_part_end) &&
	test_if_order_by_key(order, table, nr, &not_used))
    {
      min_length= table->key_info[nr].key_length;
      best= nr;
    }
  }
  return best;
}
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/*
  Test if we can skip the ORDER BY by using an index.

  If we can use an index, the JOIN_TAB / tab->select struct
  is changed to use the index.

  Return:
     0 We have to use filesort to do the sorting
     1 We can use an index.
*/
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static bool
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test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
			bool no_changes)
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{
  int ref_key;
6939
  uint ref_key_parts;
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  TABLE *table=tab->table;
  SQL_SELECT *select=tab->select;
  key_map usable_keys;
  DBUG_ENTER("test_if_skip_sort_order");
6944
  LINT_INIT(ref_key_parts);
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  /* Check which keys can be used to resolve ORDER BY */
6947
  usable_keys.set_all();
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  for (ORDER *tmp_order=order; tmp_order ; tmp_order=tmp_order->next)
  {
    if ((*tmp_order->item)->type() != Item::FIELD_ITEM)
    {
6952
      usable_keys.clear_all();
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      break;
    }
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    usable_keys.intersect(
        ((Item_field*) (*tmp_order->item))->field->part_of_sortkey);
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6957
    if (usable_keys.is_clear_all())
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      break;					// No usable keys
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  }

  ref_key= -1;
6962 6963
  /* Test if constant range in WHERE */
  if (tab->ref.key >= 0)
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  {
    ref_key=	   tab->ref.key;
    ref_key_parts= tab->ref.key_parts;
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    if (tab->type == JT_REF_OR_NULL)
      DBUG_RETURN(0);
6969
  }
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  else if (select && select->quick)		// Range found by opt_range
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  {
    ref_key=	   select->quick->index;
    ref_key_parts= select->quick->used_key_parts;
  }
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  if (ref_key >= 0)
  {
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    /*
      We come here when there is a REF key.
    */
6981
    int order_direction;
6982
    uint used_key_parts;
6983
    if (!usable_keys.is_set(ref_key))
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    {
      /*
	We come here when ref_key is not among usable_keys
      */
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      uint new_ref_key;
      /*
	If using index only read, only consider other possible index only
	keys
      */
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      if (table->used_keys.is_set(ref_key))
	usable_keys.merge(table->used_keys);
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      if ((new_ref_key= test_if_subkey(order, table, ref_key, ref_key_parts,
				       usable_keys)) < MAX_KEY)
6997
      {
6998
	/* Found key that can be used to retrieve data in sorted order */
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	if (tab->ref.key >= 0)
	{
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	  tab->ref.key= new_ref_key;
	  table->file->index_init(new_ref_key);
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	}
	else
	{
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	  select->quick->index= new_ref_key;
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	  select->quick->init();
	}
7009
	ref_key= new_ref_key;
7010
      }
7011
    }
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    /* Check if we get the rows in requested sorted order by using the key */
7013
    if (usable_keys.is_set(ref_key) &&
7014 7015
	(order_direction = test_if_order_by_key(order,table,ref_key,
						&used_key_parts)))
7016
    {
7017
      if (order_direction == -1)		// If ORDER BY ... DESC
7018
      {
7019 7020
	if (select && select->quick)
	{
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	  /*
	    Don't reverse the sort order, if it's already done.
	    (In some cases test_if_order_by_key() can be called multiple times
	  */
	  if (!select->quick->reverse_sorted())
7026
	  {
7027 7028
            if (table->file->index_flags(ref_key) & HA_NOT_READ_PREFIX_LAST)
              DBUG_RETURN(0);			// Use filesort
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	    // ORDER BY range_key DESC
	    QUICK_SELECT_DESC *tmp=new QUICK_SELECT_DESC(select->quick,
							 used_key_parts);
	    if (!tmp || tmp->error)
	    {
	      delete tmp;
	      DBUG_RETURN(0);		// Reverse sort not supported
	    }
	    select->quick=tmp;
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	  }
	  DBUG_RETURN(1);
	}
	if (tab->ref.key_parts < used_key_parts)
	{
	  /*
	    SELECT * FROM t1 WHERE a=1 ORDER BY a DESC,b DESC
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	    Use a traversal function that starts by reading the last row
	    with key part (A) and then traverse the index backwards.
7048
	  */
7049
	  if (table->file->index_flags(ref_key) & HA_NOT_READ_PREFIX_LAST)
7050
	    DBUG_RETURN(0);			// Use filesort
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	  tab->read_first_record=       join_read_last_key;
	  tab->read_record.read_record= join_read_prev_same;
	  /* fall through */
7054
	}
7055
      }
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      DBUG_RETURN(1);			/* No need to sort */
7057
    }
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  }
  else
  {
    /* check if we can use a key to resolve the group */
    /* Tables using JT_NEXT are handled here */
    uint nr;
7064
    key_map keys;
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    /*
      If not used with LIMIT, only use keys if the whole query can be
      resolved with a key;  This is because filesort() is usually faster than
      retrieving all rows through an index.
    */
    if (select_limit >= table->file->records)
7072
    {
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7073
      keys=*table->file->keys_to_use_for_scanning();
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      keys.merge(table->used_keys);
    }
    else
      keys.set_all();

    keys.intersect(usable_keys);
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7081
    for (nr=0; nr < table->keys ; nr++)
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7082
    {
7083
      uint not_used;
7084
      if (keys.is_set(nr))
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      {
	int flag;
7087
	if ((flag=test_if_order_by_key(order, table, nr, &not_used)))
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	{
7089 7090 7091
	  if (!no_changes)
	  {
	    tab->index=nr;
7092 7093
	    tab->read_first_record=  (flag > 0 ? join_read_first:
				      join_read_last);
7094 7095
	    table->file->index_init(nr);
	    tab->type=JT_NEXT;	// Read with index_first(), index_next()
7096
	    if (table->used_keys.is_set(nr))
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	    {
	      table->key_read=1;
	      table->file->extra(HA_EXTRA_KEYREAD);
	    }
7101
	  }
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	  DBUG_RETURN(1);
	}
      }
    }
  }
  DBUG_RETURN(0);				// Can't use index.
}

7110

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7111
/*
7112
  If not selecting by given key, create an index how records should be read
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  SYNOPSIS
   create_sort_index()
     thd		Thread handler
     tab		Table to sort (in join structure)
     order		How table should be sorted
     filesort_limit	Max number of rows that needs to be sorted
     select_limit	Max number of rows in final output
7121
		        Used to decide if we should use index or not
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  IMPLEMENTATION
   - If there is an index that can be used, 'tab' is modified to use
     this index.
   - If no index, create with filesort() an index file that can be used to
     retrieve rows in order (should be done with 'read_record').
     The sorted data is stored in tab->table and will be freed when calling
     free_io_cache(tab->table).

  RETURN VALUES
    0		ok
    -1		Some fatal error
    1		No records
*/
7137

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7138
static int
7139
create_sort_index(THD *thd, JOIN *join, ORDER *order,
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7140
		  ha_rows filesort_limit, ha_rows select_limit)
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{
  SORT_FIELD *sortorder;
  uint length;
7144
  ha_rows examined_rows;
7145 7146 7147
  TABLE *table;
  SQL_SELECT *select;
  JOIN_TAB *tab;
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  DBUG_ENTER("create_sort_index");

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  if (join->tables == join->const_tables)
    DBUG_RETURN(0);				// One row, no need to sort
  tab=    join->join_tab + join->const_tables;
  table=  tab->table;
  select= tab->select;

7156
  if (test_if_skip_sort_order(tab,order,select_limit,0))
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    DBUG_RETURN(0);
  if (!(sortorder=make_unireg_sortorder(order,&length)))
    goto err;				/* purecov: inspected */
  /* It's not fatal if the following alloc fails */
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  table->sort.io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
                                             MYF(MY_WME | MY_ZEROFILL));
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  table->status=0;				// May be wrong if quick_select

  // If table has a range, move it to select
  if (select && !select->quick && tab->ref.key >= 0)
  {
    if (tab->quick)
    {
      select->quick=tab->quick;
      tab->quick=0;
      /* We can only use 'Only index' if quick key is same as ref_key */
      if (table->key_read && (uint) tab->ref.key != select->quick->index)
      {
	table->key_read=0;
	table->file->extra(HA_EXTRA_NO_KEYREAD);
      }
    }
    else
    {
      /*
	We have a ref on a const;  Change this to a range that filesort
	can use.
7184 7185
	For impossible ranges (like when doing a lookup on NULL on a NOT NULL
	field, quick will contain an empty record set.
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7186
      */
7187 7188
      if (!(select->quick=get_ft_or_quick_select_for_ref(tab->join->thd,
							 table, tab)))
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	goto err;
    }
  }
7192 7193
  if (table->tmp_table)
    table->file->info(HA_STATUS_VARIABLE);	// Get record count
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  table->sort.found_records=filesort(thd, table,sortorder, length,
                                     select, filesort_limit, &examined_rows);
  tab->records=table->sort.found_records;		// For SQL_CALC_ROWS
7197
  delete select;
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  tab->select=0;
  tab->select_cond=0;
  tab->type=JT_ALL;				// Read with normal read_record
  tab->read_first_record= join_init_read_record;
7202
  tab->join->examined_rows+=examined_rows;
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  if (table->key_read)				// Restore if we used indexes
  {
    table->key_read=0;
    table->file->extra(HA_EXTRA_NO_KEYREAD);
  }
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7208
  DBUG_RETURN(table->sort.found_records == HA_POS_ERROR);
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err:
  DBUG_RETURN(-1);
}

7213
/*
7214
  Add the HAVING criteria to table->select
7215 7216
*/

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7217
#ifdef NOT_YET
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static bool fix_having(JOIN *join, Item **having)
{
  (*having)->update_used_tables();	// Some tables may have been const
  JOIN_TAB *table=&join->join_tab[join->const_tables];
  table_map used_tables= join->const_table_map | table->table->map;

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7224
  DBUG_EXECUTE("where",print_where(*having,"having"););
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  Item* sort_table_cond=make_cond_for_table(*having,used_tables,used_tables);
  if (sort_table_cond)
  {
    if (!table->select)
      if (!(table->select=new SQL_SELECT))
	return 1;
    if (!table->select->cond)
      table->select->cond=sort_table_cond;
    else					// This should never happen
      if (!(table->select->cond=new Item_cond_and(table->select->cond,
						  sort_table_cond)))
	return 1;
    table->select_cond=table->select->cond;
7238
    table->select_cond->top_level_item();
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    DBUG_EXECUTE("where",print_where(table->select_cond,
				     "select and having"););
    *having=make_cond_for_table(*having,~ (table_map) 0,~used_tables);
    DBUG_EXECUTE("where",print_where(*having,"having after make_cond"););
  }
  return 0;
}
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7246
#endif
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7249
/*****************************************************************************
7250 7251 7252 7253 7254
  Remove duplicates from tmp table
  This should be recoded to add a unique index to the table and remove
  duplicates
  Table is a locked single thread table
  fields is the number of fields to check (from the end)
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*****************************************************************************/

static bool compare_record(TABLE *table, Field **ptr)
{
  for (; *ptr ; ptr++)
  {
    if ((*ptr)->cmp_offset(table->rec_buff_length))
      return 1;
  }
  return 0;
}

static bool copy_blobs(Field **ptr)
{
  for (; *ptr ; ptr++)
  {
    if ((*ptr)->flags & BLOB_FLAG)
      if (((Field_blob *) (*ptr))->copy())
	return 1;				// Error
  }
  return 0;
}

static void free_blobs(Field **ptr)
{
  for (; *ptr ; ptr++)
  {
    if ((*ptr)->flags & BLOB_FLAG)
      ((Field_blob *) (*ptr))->free();
  }
}


static int
7289
remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
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{
  int error;
  ulong reclength,offset;
  uint field_count;
7294
  THD *thd= join->thd;
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  DBUG_ENTER("remove_duplicates");

  entry->reginfo.lock_type=TL_WRITE;

  /* Calculate how many saved fields there is in list */
  field_count=0;
  List_iterator<Item> it(fields);
  Item *item;
  while ((item=it++))
7304
  {
7305
    if (item->get_tmp_table_field() && ! item->const_item())
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      field_count++;
7307
  }
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  if (!field_count)
  {						// only const items
7311
    join->unit->select_limit_cnt= 1;		// Only send first row
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    DBUG_RETURN(0);
  }
  Field **first_field=entry->field+entry->fields - field_count;
  offset=entry->field[entry->fields - field_count]->offset();
  reclength=entry->reclength-offset;

  free_io_cache(entry);				// Safety
  entry->file->info(HA_STATUS_VARIABLE);
  if (entry->db_type == DB_TYPE_HEAP ||
      (!entry->blob_fields &&
7322
       ((ALIGN_SIZE(reclength) + HASH_OVERHEAD) * entry->file->records <
7323
	thd->variables.sortbuff_size)))
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    error=remove_dup_with_hash_index(join->thd, entry,
				     field_count, first_field,
7326
				     reclength, having);
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7327
  else
7328 7329
    error=remove_dup_with_compare(join->thd, entry, first_field, offset,
				  having);
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  free_blobs(first_field);
  DBUG_RETURN(error);
}


static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
7337
				   ulong offset, Item *having)
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{
  handler *file=table->file;
  char *org_record,*new_record;
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7341
  byte *record;
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  int error;
  ulong reclength=table->reclength-offset;
  DBUG_ENTER("remove_dup_with_compare");

7346
  org_record=(char*) (record=table->record[0])+offset;
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  new_record=(char*) table->record[1]+offset;

  file->rnd_init();
7350
  error=file->rnd_next(record);
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  for (;;)
  {
    if (thd->killed)
    {
      my_error(ER_SERVER_SHUTDOWN,MYF(0));
      error=0;
      goto err;
    }
    if (error)
    {
      if (error == HA_ERR_RECORD_DELETED)
	continue;
      if (error == HA_ERR_END_OF_FILE)
	break;
      goto err;
    }
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    if (having && !having->val_int())
    {
      if ((error=file->delete_row(record)))
	goto err;
7371
      error=file->rnd_next(record);
7372 7373
      continue;
    }
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    if (copy_blobs(first_field))
    {
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      my_error(ER_OUTOFMEMORY,MYF(0));
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      error=0;
      goto err;
    }
    memcpy(new_record,org_record,reclength);

    /* Read through rest of file and mark duplicated rows deleted */
    bool found=0;
    for (;;)
    {
7386
      if ((error=file->rnd_next(record)))
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      {
	if (error == HA_ERR_RECORD_DELETED)
	  continue;
	if (error == HA_ERR_END_OF_FILE)
	  break;
	goto err;
      }
      if (compare_record(table, first_field) == 0)
      {
7396
	if ((error=file->delete_row(record)))
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	  goto err;
      }
      else if (!found)
      {
	found=1;
7402
	file->position(record);	// Remember position
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      }
    }
    if (!found)
      break;					// End of file
    /* Restart search on next row */
7408
    error=file->restart_rnd_next(record,file->ref);
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  }

  file->extra(HA_EXTRA_NO_CACHE);
  DBUG_RETURN(0);
err:
  file->extra(HA_EXTRA_NO_CACHE);
  if (error)
    file->print_error(error,MYF(0));
  DBUG_RETURN(1);
}


/*
  Generate a hash index for each row to quickly find duplicate rows
  Note that this will not work on tables with blobs!
*/

static int remove_dup_with_hash_index(THD *thd, TABLE *table,
				      uint field_count,
				      Field **first_field,
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				      ulong key_length,
				      Item *having)
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{
  byte *key_buffer, *key_pos, *record=table->record[0];
  int error;
  handler *file=table->file;
  ulong extra_length=ALIGN_SIZE(key_length)-key_length;
  uint *field_lengths,*field_length;
  HASH hash;
  DBUG_ENTER("remove_dup_with_hash_index");

  if (!my_multi_malloc(MYF(MY_WME),
		       &key_buffer,
		       (uint) ((key_length + extra_length) *
			       (long) file->records),
		       &field_lengths,
		       (uint) (field_count*sizeof(*field_lengths)),
		       NullS))
    DBUG_RETURN(1);
7448

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  if (hash_init(&hash, &my_charset_bin, (uint) file->records, 0, 
7450
		key_length,(hash_get_key) 0, 0, 0))
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  {
    my_free((char*) key_buffer,MYF(0));
    DBUG_RETURN(1);
  }
  {
    Field **ptr;
    for (ptr= first_field, field_length=field_lengths ; *ptr ; ptr++)
      (*field_length++)= (*ptr)->pack_length();
  }

  file->rnd_init();
  key_pos=key_buffer;
  for (;;)
  {
    if (thd->killed)
    {
      my_error(ER_SERVER_SHUTDOWN,MYF(0));
      error=0;
      goto err;
    }
    if ((error=file->rnd_next(record)))
    {
      if (error == HA_ERR_RECORD_DELETED)
	continue;
      if (error == HA_ERR_END_OF_FILE)
	break;
      goto err;
    }
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    if (having && !having->val_int())
    {
      if ((error=file->delete_row(record)))
	goto err;
      continue;
7484
    }
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    /* copy fields to key buffer */
    field_length=field_lengths;
    for (Field **ptr= first_field ; *ptr ; ptr++)
    {
      (*ptr)->sort_string((char*) key_pos,*field_length);
      key_pos+= *field_length++;
    }
    /* Check if it exists before */
    if (hash_search(&hash,key_pos-key_length,key_length))
    {
      /* Duplicated found ; Remove the row */
      if ((error=file->delete_row(record)))
	goto err;
    }
7500
    else
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      (void) my_hash_insert(&hash, key_pos-key_length);
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    key_pos+=extra_length;
  }
  my_free((char*) key_buffer,MYF(0));
  hash_free(&hash);
  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->rnd_end();
  DBUG_RETURN(0);

err:
  my_free((char*) key_buffer,MYF(0));
  hash_free(&hash);
  file->extra(HA_EXTRA_NO_CACHE);
  (void) file->rnd_end();
  if (error)
    file->print_error(error,MYF(0));
  DBUG_RETURN(1);
}


7521
SORT_FIELD *make_unireg_sortorder(ORDER *order, uint *length)
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{
  uint count;
  SORT_FIELD *sort,*pos;
  DBUG_ENTER("make_unireg_sortorder");

  count=0;
  for (ORDER *tmp = order; tmp; tmp=tmp->next)
    count++;
  pos=sort=(SORT_FIELD*) sql_alloc(sizeof(SORT_FIELD)*(count+1));
  if (!pos)
    return 0;

  for (;order;order=order->next,pos++)
  {
    pos->field=0; pos->item=0;
    if (order->item[0]->type() == Item::FIELD_ITEM)
      pos->field= ((Item_field*) (*order->item))->field;
    else if (order->item[0]->type() == Item::SUM_FUNC_ITEM &&
	     !order->item[0]->const_item())
7541
      pos->field= ((Item_sum*) order->item[0])->get_tmp_table_field();
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    else if (order->item[0]->type() == Item::COPY_STR_ITEM)
    {						// Blob patch
      pos->item= ((Item_copy_string*) (*order->item))->item;
    }
    else
      pos->item= *order->item;
    pos->reverse=! order->asc;
  }
  *length=count;
  DBUG_RETURN(sort);
}


/*****************************************************************************
7556 7557 7558 7559
  Fill join cache with packed records
  Records are stored in tab->cache.buffer and last record in
  last record is stored with pointers to blobs to support very big
  records
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******************************************************************************/

static int
join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
{
  reg1 uint i;
  uint length,blobs,size;
  CACHE_FIELD *copy,**blob_ptr;
  JOIN_CACHE  *cache;
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  JOIN_TAB *join_tab;
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  DBUG_ENTER("join_init_cache");

  cache= &tables[table_count].cache;
  cache->fields=blobs=0;

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  join_tab=tables;
  for (i=0 ; i < table_count ; i++,join_tab++)
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  {
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    if (!join_tab->used_fieldlength)		/* Not calced yet */
      calc_used_field_length(thd, join_tab);
    cache->fields+=join_tab->used_fields;
    blobs+=join_tab->used_blobs;
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  }
  if (!(cache->field=(CACHE_FIELD*)
	sql_alloc(sizeof(CACHE_FIELD)*(cache->fields+table_count*2)+(blobs+1)*
		  sizeof(CACHE_FIELD*))))
  {
    my_free((gptr) cache->buff,MYF(0));		/* purecov: inspected */
    cache->buff=0;				/* purecov: inspected */
    DBUG_RETURN(1);				/* purecov: inspected */
  }
  copy=cache->field;
  blob_ptr=cache->blob_ptr=(CACHE_FIELD**)
    (cache->field+cache->fields+table_count*2);

  length=0;
  for (i=0 ; i < table_count ; i++)
  {
    uint null_fields=0,used_fields;

    Field **f_ptr,*field;
    for (f_ptr=tables[i].table->field,used_fields=tables[i].used_fields ;
	 used_fields ;
	 f_ptr++)
    {
      field= *f_ptr;
      if (field->query_id == thd->query_id)
      {
	used_fields--;
	length+=field->fill_cache_field(copy);
	if (copy->blob_field)
	  (*blob_ptr++)=copy;
	if (field->maybe_null())
	  null_fields++;
	copy++;
      }
    }
    /* Copy null bits from table */
    if (null_fields && tables[i].table->null_fields)
    {						/* must copy null bits */
      copy->str=(char*) tables[i].table->null_flags;
7621
      copy->length=tables[i].table->null_bytes;
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      copy->strip=0;
      copy->blob_field=0;
      length+=copy->length;
      copy++;
      cache->fields++;
    }
    /* If outer join table, copy null_row flag */
    if (tables[i].table->maybe_null)
    {
      copy->str= (char*) &tables[i].table->null_row;
      copy->length=sizeof(tables[i].table->null_row);
      copy->strip=0;
      copy->blob_field=0;
      length+=copy->length;
      copy++;
      cache->fields++;
    }
  }

  cache->records=0; cache->ptr_record= (uint) ~0;
  cache->length=length+blobs*sizeof(char*);
  cache->blobs=blobs;
  *blob_ptr=0;					/* End sequentel */
7645
  size=max(thd->variables.join_buff_size, cache->length);
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  if (!(cache->buff=(uchar*) my_malloc(size,MYF(0))))
    DBUG_RETURN(1);				/* Don't use cache */ /* purecov: inspected */
  cache->end=cache->buff+size;
  reset_cache(cache);
  DBUG_RETURN(0);
}


static ulong
used_blob_length(CACHE_FIELD **ptr)
{
  uint length,blob_length;
  for (length=0 ; *ptr ; ptr++)
  {
    (*ptr)->blob_length=blob_length=(*ptr)->blob_field->get_length();
    length+=blob_length;
    (*ptr)->blob_field->get_ptr(&(*ptr)->str);
  }
  return length;
}


static bool
store_record_in_cache(JOIN_CACHE *cache)
{
  ulong length;
  uchar *pos;
  CACHE_FIELD *copy,*end_field;
  bool last_record;

  pos=cache->pos;
  end_field=cache->field+cache->fields;

  length=cache->length;
  if (cache->blobs)
    length+=used_blob_length(cache->blob_ptr);
  if ((last_record=(length+cache->length > (uint) (cache->end - pos))))
    cache->ptr_record=cache->records;

  /*
7686
    There is room in cache. Put record there
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  */
  cache->records++;
  for (copy=cache->field ; copy < end_field; copy++)
  {
    if (copy->blob_field)
    {
      if (last_record)
      {
7695 7696
	copy->blob_field->get_image((char*) pos,copy->length+sizeof(char*), 
				    copy->blob_field->charset());
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	pos+=copy->length+sizeof(char*);
      }
      else
      {
7701 7702
	copy->blob_field->get_image((char*) pos,copy->length, // blob length
				    copy->blob_field->charset());
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	memcpy(pos+copy->length,copy->str,copy->blob_length);  // Blob data
	pos+=copy->length+copy->blob_length;
      }
    }
    else
    {
      if (copy->strip)
      {
	char *str,*end;
	for (str=copy->str,end= str+copy->length;
	     end > str && end[-1] == ' ' ;
	     end--) ;
	length=(uint) (end-str);
	memcpy(pos+1,str,length);
	*pos=(uchar) length;
	pos+=length+1;
      }
      else
      {
	memcpy(pos,copy->str,copy->length);
	pos+=copy->length;
      }
    }
  }
  cache->pos=pos;
  return last_record || (uint) (cache->end -pos) < cache->length;
}


static void
reset_cache(JOIN_CACHE *cache)
{
  cache->record_nr=0;
  cache->pos=cache->buff;
}


static void
read_cached_record(JOIN_TAB *tab)
{
  uchar *pos;
  uint length;
  bool last_record;
  CACHE_FIELD *copy,*end_field;

  last_record=tab->cache.record_nr++ == tab->cache.ptr_record;
  pos=tab->cache.pos;

  for (copy=tab->cache.field,end_field=copy+tab->cache.fields ;
       copy < end_field;
       copy++)
  {
    if (copy->blob_field)
    {
      if (last_record)
      {
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	copy->blob_field->set_image((char*) pos,copy->length+sizeof(char*),
				    copy->blob_field->charset());
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	pos+=copy->length+sizeof(char*);
      }
      else
      {
	copy->blob_field->set_ptr((char*) pos,(char*) pos+copy->length);
	pos+=copy->length+copy->blob_field->get_length();
      }
    }
    else
    {
      if (copy->strip)
      {
	memcpy(copy->str,pos+1,length=(uint) *pos);
	memset(copy->str+length,' ',copy->length-length);
	pos+=1+length;
      }
      else
      {
	memcpy(copy->str,pos,copy->length);
	pos+=copy->length;
      }
    }
  }
  tab->cache.pos=pos;
  return;
}


static bool
cmp_buffer_with_ref(JOIN_TAB *tab)
{
  bool diff;
  if (!(diff=tab->ref.key_err))
  {
    memcpy(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length);
  }
  if ((tab->ref.key_err=cp_buffer_from_ref(&tab->ref)) || diff)
    return 1;
  return memcmp(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length)
    != 0;
}


bool
cp_buffer_from_ref(TABLE_REF *ref)
{
  for (store_key **copy=ref->key_copy ; *copy ; copy++)
    if ((*copy)->copy())
      return 1;					// Something went wrong
  return 0;
}


/*****************************************************************************
7815
  Group and order functions
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*****************************************************************************/

/*
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  Find order/group item in requested columns and change the item to point at
  it. If item doesn't exists, add it first in the field list
  Return 0 if ok.
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*/

static int
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find_order_in_list(THD *thd, Item **ref_pointer_array,
		   TABLE_LIST *tables,ORDER *order, List<Item> &fields,
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		   List<Item> &all_fields)
{
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  Item *itemptr=*order->item;
  if (itemptr->type() == Item::INT_ITEM)
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  {						/* Order by position */
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    uint count= (uint) ((Item_int*)itemptr)->value;
7833
    if (!count || count > fields.elements)
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    {
      my_printf_error(ER_BAD_FIELD_ERROR,ER(ER_BAD_FIELD_ERROR),
7836
		      MYF(0),itemptr->full_name(),
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	       thd->where);
      return 1;
    }
7840 7841
    order->item= ref_pointer_array + count-1;
    order->in_field_list= 1;
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    return 0;
  }
7844
  uint counter;
7845
  Item **item= find_item_in_list(itemptr, fields, &counter, IGNORE_ERRORS);
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  if (item)
  {
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    order->item= ref_pointer_array + counter;
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    order->in_field_list=1;
    return 0;
  }
  order->in_field_list=0;
7853
  Item *it= *order->item;
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  if (it->fix_fields(thd, tables, order->item) ||
      //'it' ressigned because fix_field can change it
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      (it= *order->item)->check_cols(1) ||
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      thd->is_fatal_error)
7858
    return 1;					// Wrong field 
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  uint el= all_fields.elements;
  all_fields.push_front(it);		        // Add new field to field list
  ref_pointer_array[el]= it;
  order->item= ref_pointer_array + el;
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  return 0;
}

/*
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  Change order to point at item in select list. If item isn't a number
  and doesn't exits in the select list, add it the the field list.
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*/

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int setup_order(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
		List<Item> &fields, List<Item> &all_fields, ORDER *order)
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{
  thd->where="order clause";
  for (; order; order=order->next)
  {
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    if (find_order_in_list(thd, ref_pointer_array, tables, order, fields,
			   all_fields))
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      return 1;
  }
  return 0;
}


7885
int
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setup_group(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
	    List<Item> &fields, List<Item> &all_fields, ORDER *order,
	    bool *hidden_group_fields)
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{
  *hidden_group_fields=0;
  if (!order)
    return 0;				/* Everything is ok */

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  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
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  {
    Item *item;
    List_iterator<Item> li(fields);
    while ((item=li++))
      item->marker=0;			/* Marker that field is not used */
  }
  uint org_fields=all_fields.elements;

  thd->where="group statement";
7904
  for (; order; order=order->next)
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  {
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    if (find_order_in_list(thd, ref_pointer_array, tables, order, fields,
			   all_fields))
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      return 1;
    (*order->item)->marker=1;		/* Mark found */
    if ((*order->item)->with_sum_func)
    {
      my_printf_error(ER_WRONG_GROUP_FIELD, ER(ER_WRONG_GROUP_FIELD),MYF(0),
		      (*order->item)->full_name());
      return 1;
    }
  }
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  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
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  {
    /* Don't allow one to use fields that is not used in GROUP BY */
    Item *item;
    List_iterator<Item> li(fields);

    while ((item=li++))
    {
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      if (item->type() != Item::SUM_FUNC_ITEM && !item->marker &&
	  !item->const_item())
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      {
	my_printf_error(ER_WRONG_FIELD_WITH_GROUP,
			ER(ER_WRONG_FIELD_WITH_GROUP),
			MYF(0),item->full_name());
	return 1;
      }
    }
  }
  if (org_fields != all_fields.elements)
    *hidden_group_fields=1;			// group fields is not used
  return 0;
}

/*
7941
  Add fields with aren't used at start of field list. Return FALSE if ok
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*/

static bool
setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
		 List<Item> &all_fields, ORDER *new_field)
{
  Item	  **item;
  DBUG_ENTER("setup_new_fields");

  thd->set_query_id=1;				// Not really needed, but...
7952
  uint counter;
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  for (; new_field ; new_field= new_field->next)
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  {
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    if ((item= find_item_in_list(*new_field->item, fields, &counter,
				 IGNORE_ERRORS)))
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      new_field->item=item;			/* Change to shared Item */
    else
    {
      thd->where="procedure list";
7961
      if ((*new_field->item)->fix_fields(thd, tables, new_field->item))
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	DBUG_RETURN(1); /* purecov: inspected */
      all_fields.push_front(*new_field->item);
      new_field->item=all_fields.head_ref();
    }
  }
  DBUG_RETURN(0);
}

/*
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  Create a group by that consist of all non const fields. Try to use
  the fields in the order given by 'order' to allow one to optimize
  away 'order by'.
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*/

static ORDER *
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create_distinct_group(THD *thd, ORDER *order_list, List<Item> &fields, 
		      bool *all_order_by_fields_used)
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{
  List_iterator<Item> li(fields);
  Item *item;
  ORDER *order,*group,**prev;

7984
  *all_order_by_fields_used= 1;
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  while ((item=li++))
    item->marker=0;			/* Marker that field is not used */

  prev= &group;  group=0;
  for (order=order_list ; order; order=order->next)
  {
    if (order->in_field_list)
    {
7993
      ORDER *ord=(ORDER*) thd->memdup((char*) order,sizeof(ORDER));
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      if (!ord)
	return 0;
      *prev=ord;
      prev= &ord->next;
      (*ord->item)->marker=1;
    }
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    else
      *all_order_by_fields_used= 0;
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  }

  li.rewind();
  while ((item=li++))
  {
    if (item->const_item() || item->with_sum_func)
      continue;
    if (!item->marker)
    {
8011
      ORDER *ord=(ORDER*) thd->calloc(sizeof(ORDER));
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      if (!ord)
	return 0;
      ord->item=li.ref();
      ord->asc=1;
      *prev=ord;
      prev= &ord->next;
    }
  }
  *prev=0;
  return group;
}


/*****************************************************************************
8026
  Update join with count of the different type of fields
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*****************************************************************************/

void
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count_field_types(TMP_TABLE_PARAM *param, List<Item> &fields,
		  bool reset_with_sum_func)
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{
  List_iterator<Item> li(fields);
  Item *field;

8036
  param->field_count=param->sum_func_count=param->func_count=
8037
    param->hidden_field_count=0;
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  param->quick_group=1;
  while ((field=li++))
  {
    Item::Type type=field->type();
    if (type == Item::FIELD_ITEM)
      param->field_count++;
    else if (type == Item::SUM_FUNC_ITEM)
    {
      if (! field->const_item())
      {
	Item_sum *sum_item=(Item_sum*) field;
	if (!sum_item->quick_group)
	  param->quick_group=0;			// UDF SUM function
	param->sum_func_count++;

	for (uint i=0 ; i < sum_item->arg_count ; i++)
	{
	  if (sum_item->args[0]->type() == Item::FIELD_ITEM)
	    param->field_count++;
	  else
	    param->func_count++;
	}
      }
    }
    else
8063
    {
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      param->func_count++;
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      if (reset_with_sum_func)
	field->with_sum_func=0;
    }
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  }
}


/*
  Return 1 if second is a subpart of first argument
  If first parts has different direction, change it to second part
  (group is sorted like order)
*/

static bool
test_if_subpart(ORDER *a,ORDER *b)
{
  for (; a && b; a=a->next,b=b->next)
  {
8083
    if ((*a->item)->eq(*b->item,1))
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      a->asc=b->asc;
    else
      return 0;
  }
  return test(!b);
}

/*
  Return table number if there is only one table in sort order
  and group and order is compatible
  else return 0;
*/

static TABLE *
get_sort_by_table(ORDER *a,ORDER *b,TABLE_LIST *tables)
{
  table_map map= (table_map) 0;
  DBUG_ENTER("get_sort_by_table");

  if (!a)
    a=b;					// Only one need to be given
  else if (!b)
    b=a;

  for (; a && b; a=a->next,b=b->next)
  {
8110
    if (!(*a->item)->eq(*b->item,1))
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      DBUG_RETURN(0);
    map|=a->item[0]->used_tables();
  }
8114
  if (!map || (map & (RAND_TABLE_BIT | OUTER_REF_TABLE_BIT)))
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    DBUG_RETURN(0);

8117
  for (; !(map & tables->table->map) ; tables=tables->next) ;
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  if (map != tables->table->map)
    DBUG_RETURN(0);				// More than one table
  DBUG_PRINT("exit",("sort by table: %d",tables->table->tablenr));
  DBUG_RETURN(tables->table);
}


	/* calc how big buffer we need for comparing group entries */

static void
calc_group_buffer(JOIN *join,ORDER *group)
{
8130 8131
  uint key_length=0, parts=0, null_parts=0;

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  if (group)
    join->group= 1;
  for (; group ; group=group->next)
  {
8136
    Field *field=(*group->item)->get_tmp_table_field();
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    if (field)
    {
      if (field->type() == FIELD_TYPE_BLOB)
	key_length+=MAX_BLOB_WIDTH;		// Can't be used as a key
      else
	key_length+=field->pack_length();
    }
    else if ((*group->item)->result_type() == REAL_RESULT)
      key_length+=sizeof(double);
    else if ((*group->item)->result_type() == INT_RESULT)
      key_length+=sizeof(longlong);
    else
      key_length+=(*group->item)->max_length;
    parts++;
    if ((*group->item)->maybe_null)
8152
      null_parts++;
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8153
  }
8154
  join->tmp_table_param.group_length=key_length+null_parts;
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  join->tmp_table_param.group_parts=parts;
8156
  join->tmp_table_param.group_null_parts=null_parts;
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}

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/*
  alloc group fields or take prepared (chached)

  SYNOPSYS
    make_group_fields()
    main_join - join of current select
    curr_join - current join (join of current select or temporary copy of it)

  RETURN
    0 - ok
    1 - failed
*/

static bool
make_group_fields(JOIN *main_join, JOIN *curr_join)
{
    if (main_join->group_fields_cache.elements)
    {
      curr_join->group_fields= main_join->group_fields_cache;
      curr_join->sort_and_group= 1;
    }
    else
    {
      if (alloc_group_fields(curr_join, curr_join->group_list))
      {
	return (1);
      }
      main_join->group_fields_cache= curr_join->group_fields;
    }
    return (0);
}
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/*
8192 8193
  Get a list of buffers for saveing last group
  Groups are saved in reverse order for easyer check loop
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*/

static bool
alloc_group_fields(JOIN *join,ORDER *group)
{
  if (group)
  {
    for (; group ; group=group->next)
    {
      Item_buff *tmp=new_Item_buff(*group->item);
      if (!tmp || join->group_fields.push_front(tmp))
	return TRUE;
    }
  }
  join->sort_and_group=1;			/* Mark for do_select */
  return FALSE;
}


static int
test_if_group_changed(List<Item_buff> &list)
{
8216
  DBUG_ENTER("test_if_group_changed");
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  List_iterator<Item_buff> li(list);
  int idx= -1,i;
  Item_buff *buff;

  for (i=(int) list.elements-1 ; (buff=li++) ; i--)
  {
    if (buff->cmp())
      idx=i;
  }
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  DBUG_PRINT("info", ("idx: %d", idx));
  DBUG_RETURN(idx);
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}



/*
8233
  Setup copy_fields to save fields at start of new group
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  setup_copy_fields()
    thd - THD pointer
    param - temporary table parameters
    ref_pointer_array - array of pointers to top elements of filed list
    res_selected_fields - new list of items of select item list
    res_all_fields - new list of all items
    elements - number of elements in select item list
    all_fields - all fields list

  DESCRIPTION
    Setup copy_fields to save fields at start of new group
    Only FIELD_ITEM:s and FUNC_ITEM:s needs to be saved between groups.
    Change old item_field to use a new field with points at saved fieldvalue
    This function is only called before use of send_fields
  
  RETURN
    0 - ok
    !=0 - error
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*/

bool
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setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
		  Item **ref_pointer_array,
8258 8259
		  List<Item> &res_selected_fields, List<Item> &res_all_fields,
		  uint elements, List<Item> &all_fields)
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{
  Item *pos;
8262
  List_iterator_fast<Item> li(all_fields);
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  Copy_field *copy;
  DBUG_ENTER("setup_copy_fields");
8265 8266 8267
  res_selected_fields.empty();
  res_all_fields.empty();
  List_iterator_fast<Item> itr(res_all_fields);
8268

8269
  uint i, border= all_fields.elements - elements;
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  if (!(copy=param->copy_field= new Copy_field[param->field_count]))
8272
    goto err2;
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  param->copy_funcs.empty();
8275
  for (i= 0; (pos= li++); i++)
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  {
    if (pos->type() == Item::FIELD_ITEM)
    {
8279
      Item_field *item;
8280
      if (!(item= new Item_field(thd, ((Item_field*) pos))))
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	goto err;
      pos= item;
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      if (item->field->flags & BLOB_FLAG)
      {
8285
	if (!(pos= new Item_copy_string(pos)))
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	  goto err;
	if (param->copy_funcs.push_back(pos))
	  goto err;
      }
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      else
      {
	/* 
	   set up save buffer and change result_field to point at 
	   saved value
	*/
	Field *field= item->field;
	item->result_field=field->new_field(&thd->mem_root,field->table);
	char *tmp=(char*) sql_alloc(field->pack_length()+1);
	if (!tmp)
	  goto err;
	copy->set(tmp, item->result_field);
	item->result_field->move_field(copy->to_ptr,copy->to_null_ptr,1);
	copy++;
      }
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    }
    else if ((pos->type() == Item::FUNC_ITEM ||
	      pos->type() == Item::COND_ITEM) &&
	     !pos->with_sum_func)
    {						// Save for send fields
      /* TODO:
	 In most cases this result will be sent to the user.
	 This should be changed to use copy_int or copy_real depending
	 on how the value is to be used: In some cases this may be an
	 argument in a group function, like: IF(ISNULL(col),0,COUNT(*))
      */
      if (!(pos=new Item_copy_string(pos)))
	goto err;
      if (param->copy_funcs.push_back(pos))
	goto err;
    }
8321 8322
    res_all_fields.push_back(pos);
    ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
8323
      pos;
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  }
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  param->copy_field_end= copy;
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  for (i= 0; i < border; i++)
    itr++;
8329
  itr.sublist(res_selected_fields, elements);
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  DBUG_RETURN(0);

 err:
8333
  delete [] param->copy_field;			// This is never 0
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8334
  param->copy_field=0;
8335
err2:
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  DBUG_RETURN(TRUE);
}


/*
8341 8342 8343 8344
  Make a copy of all simple SELECT'ed items

  This is done at the start of a new group so that we can retrieve
  these later when the group changes.
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*/

void
copy_fields(TMP_TABLE_PARAM *param)
{
  Copy_field *ptr=param->copy_field;
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  Copy_field *end=param->copy_field_end;
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8353
  for (; ptr != end; ptr++)
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    (*ptr->do_copy)(ptr);

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  List_iterator_fast<Item> &it=param->copy_funcs_it;
  it.rewind();
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  Item_copy_string *item;
  while ((item = (Item_copy_string*) it++))
    item->copy();
}


8364 8365
/*
  Make an array of pointers to sum_functions to speed up sum_func calculation
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8366

8367 8368 8369 8370 8371 8372 8373 8374 8375
  SYNOPSIS
    alloc_func_list()

  RETURN
    0	ok
    1	Error
*/

bool JOIN::alloc_func_list()
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{
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  uint func_count, group_parts;
  DBUG_ENTER("alloc_func_list");

  func_count= tmp_table_param.sum_func_count;
  /*
    If we are using rollup, we need a copy of the summary functions for
    each level
  */
  if (rollup.state != ROLLUP::STATE_NONE)
    func_count*= (send_group_parts+1);

  group_parts= send_group_parts;
  /*
    If distinct, reserve memory for possible
    disctinct->group_by optimization
  */
  if (select_distinct)
    group_parts+= fields_list.elements;

  /* This must use calloc() as rollup_make_fields depends on this */
  sum_funcs= (Item_sum**) thd->calloc(sizeof(Item_sum**) * (func_count+1) +
				      sizeof(Item_sum***) * (group_parts+1));
  sum_funcs_end= (Item_sum***) (sum_funcs+func_count+1);
  DBUG_RETURN(sum_funcs == 0);
}


8404
bool JOIN::make_sum_func_list(List<Item> &field_list, List<Item> &send_fields,
8405
			      bool before_group_by)
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{
8407
  List_iterator_fast<Item> it(field_list);
8408 8409
  Item_sum **func;
  Item *item;
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  DBUG_ENTER("make_sum_func_list");

8412 8413
  func= sum_funcs;
  while ((item=it++))
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  {
8415
    if (item->type() == Item::SUM_FUNC_ITEM && !item->const_item())
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    {
8417
      *func++= (Item_sum*) item;
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      /* let COUNT(DISTINCT) create the temporary table */
8419
      if (((Item_sum*) item)->setup(thd))
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	DBUG_RETURN(TRUE);
    }
  }
8423 8424 8425
  if (before_group_by && rollup.state == ROLLUP::STATE_INITED)
  {
    rollup.state= ROLLUP::STATE_READY;
8426
    if (rollup_make_fields(field_list, send_fields, &func))
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      DBUG_RETURN(TRUE);			// Should never happen
  }
  else if (rollup.state == ROLLUP::STATE_NONE)
  {
    for (uint i=0 ; i <= send_group_parts ;i++)
      sum_funcs_end[i]= func;
  }
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  *func=0;					// End marker
  DBUG_RETURN(FALSE);
}


/*
8440
  Change all funcs and sum_funcs to fields in tmp table,  and create
8441 8442 8443 8444 8445 8446 8447 8448 8449 8450 8451 8452 8453
  new list of all items.

  change_to_use_tmp_fields()
    thd - THD pointer
    ref_pointer_array - array of pointers to top elements of filed list
    res_selected_fields - new list of items of select item list
    res_all_fields - new list of all items
    elements - number of elements in select item list
    all_fields - all fields list

   RETURN
    0 - ok
    !=0 - error
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*/

static bool
8457
change_to_use_tmp_fields(THD *thd, Item **ref_pointer_array,
8458 8459 8460
			 List<Item> &res_selected_fields,
			 List<Item> &res_all_fields,
			 uint elements, List<Item> &all_fields)
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{
8462
  List_iterator_fast<Item> it(all_fields);
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  Item *item_field,*item;
8464 8465
  res_selected_fields.empty();
  res_all_fields.empty();
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8467
  uint i, border= all_fields.elements - elements;
8468
  for (i= 0; (item= it++); i++)
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  {
    Field *field;
8471
    
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    if (item->with_sum_func && item->type() != Item::SUM_FUNC_ITEM)
8473 8474
      item_field= item;
    else
8475
    {
8476
      if (item->type() == Item::FIELD_ITEM)
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      {
8478
	item_field= item->get_tmp_table_item(thd);
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      }
8480
      else if ((field= item->get_tmp_table_field()))
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      {
	if (item->type() == Item::SUM_FUNC_ITEM && field->table->group)
	  item_field= ((Item_sum*) item)->result_item(field);
	else
	  item_field= (Item*) new Item_field(field);
	if (!item_field)
	  return TRUE;				// Fatal error
	item_field->name= item->name;		/*lint -e613 */
#ifndef DBUG_OFF
	if (_db_on_ && !item_field->name)
	{
	  char buff[256];
8493
	  String str(buff,sizeof(buff),&my_charset_bin);
8494 8495 8496 8497
	  str.length(0);
	  item->print(&str);
	  item_field->name= sql_strmake(str.ptr(),str.length());
	}
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#endif
8499 8500 8501
      }
      else
	item_field= item;
8502 8503 8504
    }
    res_all_fields.push_back(item_field);
    ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
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      item_field;
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  }
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  List_iterator_fast<Item> itr(res_all_fields);
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  for (i= 0; i < border; i++)
    itr++;
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  itr.sublist(res_selected_fields, elements);
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  return FALSE;
}


/*
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  Change all sum_func refs to fields to point at fields in tmp table
  Change all funcs to be fields in tmp table
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  change_refs_to_tmp_fields()
    thd - THD pointer
    ref_pointer_array - array of pointers to top elements of filed list
    res_selected_fields - new list of items of select item list
    res_all_fields - new list of all items
    elements - number of elements in select item list
    all_fields - all fields list

   RETURN
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    0	ok
    1	error
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*/

static bool
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change_refs_to_tmp_fields(THD *thd, Item **ref_pointer_array,
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			  List<Item> &res_selected_fields,
			  List<Item> &res_all_fields, uint elements,
			  List<Item> &all_fields)
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{
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  List_iterator_fast<Item> it(all_fields);
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  Item *item, *new_item;
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  res_selected_fields.empty();
  res_all_fields.empty();
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  uint i, border= all_fields.elements - elements;
8545
  for (i= 0; (item= it++); i++)
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  {
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    res_all_fields.push_back(new_item= item->get_tmp_table_item(thd));
    ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
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      new_item;
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  }
8551

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  List_iterator_fast<Item> itr(res_all_fields);
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  for (i= 0; i < border; i++)
    itr++;
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  itr.sublist(res_selected_fields, elements);
8556

8557
  return thd->is_fatal_error;
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}



/******************************************************************************
8563
  Code for calculating functions
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******************************************************************************/

static void
init_tmptable_sum_functions(Item_sum **func_ptr)
{
  Item_sum *func;
  while ((func= *(func_ptr++)))
    func->reset_field();
}


	/* Update record 0 in tmp_table from record 1 */

static void
update_tmptable_sum_func(Item_sum **func_ptr,
			 TABLE *tmp_table __attribute__((unused)))
{
  Item_sum *func;
  while ((func= *(func_ptr++)))
8583
    func->update_field();
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}


	/* Copy result of sum functions to record in tmp_table */

static void
copy_sum_funcs(Item_sum **func_ptr)
{
  Item_sum *func;
  for (; (func = *func_ptr) ; func_ptr++)
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    (void) func->save_in_result_field(1);
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  return;
}


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static bool
init_sum_functions(Item_sum **func_ptr, Item_sum **end_ptr)
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{
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  for (; func_ptr != end_ptr ;func_ptr++)
  {
    if ((*func_ptr)->reset())
      return 1;
  }
  /* If rollup, calculate the upper sum levels */
  for ( ; *func_ptr ; func_ptr++)
  {
    if ((*func_ptr)->add())
      return 1;
  }
  return 0;
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}


static bool
update_sum_func(Item_sum **func_ptr)
{
  Item_sum *func;
  for (; (func= (Item_sum*) *func_ptr) ; func_ptr++)
    if (func->add())
      return 1;
  return 0;
}

	/* Copy result of functions to record in tmp_table */

void
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copy_funcs(Item **func_ptr)
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{
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  Item *func;
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  for (; (func = *func_ptr) ; func_ptr++)
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    func->save_in_result_field(1);
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}


8638
/*
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  Create a condition for a const reference and add this to the
  currenct select for the table
8641
*/
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static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab)
{
  DBUG_ENTER("add_ref_to_table_cond");
  if (!join_tab->ref.key_parts)
    DBUG_RETURN(FALSE);

  Item_cond_and *cond=new Item_cond_and();
  TABLE *table=join_tab->table;
  int error;
  if (!cond)
    DBUG_RETURN(TRUE);

  for (uint i=0 ; i < join_tab->ref.key_parts ; i++)
  {
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    Field *field=table->field[table->key_info[join_tab->ref.key].key_part[i].
			      fieldnr-1];
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    Item *value=join_tab->ref.items[i];
    cond->add(new Item_func_equal(new Item_field(field),value));
  }
8662
  if (thd->is_fatal_error)
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    DBUG_RETURN(TRUE);
8664

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  cond->fix_fields(thd,(TABLE_LIST *) 0, (Item**)&cond);
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  if (join_tab->select)
  {
    error=(int) cond->add(join_tab->select->cond);
    join_tab->select_cond=join_tab->select->cond=cond;
  }
  else if ((join_tab->select=make_select(join_tab->table, 0, 0, cond,&error)))
    join_tab->select_cond=cond;

  DBUG_RETURN(error ? TRUE : FALSE);
}

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/*
  Free joins of subselect of this select.

  free_underlaid_joins()
    thd - THD pointer
    select - pointer to st_select_lex which subselects joins we will free
*/

void free_underlaid_joins(THD *thd, SELECT_LEX *select)
{
  for (SELECT_LEX_UNIT *unit= select->first_inner_unit();
       unit;
       unit= unit->next_unit())
    unit->cleanup();
}

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/****************************************************************************
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  ROLLUP handling
****************************************************************************/

/* Allocate memory needed for other rollup functions */

bool JOIN::rollup_init()
{
  uint i,j;
  Item **ref_array;

  tmp_table_param.quick_group= 0;	// Can't create groups in tmp table
  rollup.state= ROLLUP::STATE_INITED;

  /*
    Create pointers to the different sum function groups
    These are updated by rollup_make_fields()
  */
  tmp_table_param.group_parts= send_group_parts;

  if (!(rollup.fields= (List<Item>*) thd->alloc((sizeof(Item*) +
						 sizeof(List<Item>) +
						 ref_pointer_array_size)
						* send_group_parts)))
    return 1;
  rollup.ref_pointer_arrays= (Item***) (rollup.fields + send_group_parts);
  ref_array= (Item**) (rollup.ref_pointer_arrays+send_group_parts);
  rollup.item_null= new (&thd->mem_root) Item_null();

  /*
    Prepare space for field list for the different levels
    These will be filled up in rollup_make_fields()
  */
  for (i= 0 ; i < send_group_parts ; i++)
  {
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    List<Item> *rollup_fields= &rollup.fields[i];
    rollup_fields->empty();
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    rollup.ref_pointer_arrays[i]= ref_array;
    ref_array+= all_fields.elements;
    for (j=0 ; j < fields_list.elements ; j++)
8734
      rollup_fields->push_back(rollup.item_null);
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  }
  return 0;
}
  

/*
  Fill up rollup structures with pointers to fields to use

  SYNOPSIS
    rollup_make_fields()
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    fields_arg			List of all fields (hidden and real ones)
    sel_fields			Pointer to selected fields
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    func			Store here a pointer to all fields

  IMPLEMENTATION:
    Creates copies of item_sum items for each sum level

  RETURN
    0	if ok
	In this case func is pointing to next not used element.
    1   on error
*/

8758
bool JOIN::rollup_make_fields(List<Item> &fields_arg, List<Item> &sel_fields,
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			      Item_sum ***func)
{
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  List_iterator_fast<Item> it(fields_arg);
  Item *first_field= sel_fields.head();
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  uint level;

  /*
    Create field lists for the different levels

    The idea here is to have a separate field list for each rollup level to
    avoid all runtime checks of which columns should be NULL.

    The list is stored in reverse order to get sum function in such an order
    in func that it makes it easy to reset them with init_sum_functions()

    Assuming:  SELECT a, b, c SUM(b) FROM t1 GROUP BY a,b WITH ROLLUP

    rollup.fields[0] will contain list where a,b,c is NULL
    rollup.fields[1] will contain list where b,c is NULL
    ...
    rollup.ref_pointer_array[#] points to fields for rollup.fields[#]
    ...
    sum_funcs_end[0] points to all sum functions
    sum_funcs_end[1] points to all sum functions, except grand totals
    ...
  */

8786
  for (level=0 ; level < send_group_parts ; level++)
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  {
    uint i;
    uint pos= send_group_parts - level -1;
    bool real_fields= 0;
    Item *item;
    List_iterator<Item> new_it(rollup.fields[pos]);
    Item **ref_array_start= rollup.ref_pointer_arrays[pos];
    ORDER *start_group;

    /* Point to first hidden field */
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    Item **ref_array= ref_array_start + fields_arg.elements-1;
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    /* Remember where the sum functions ends for the previous level */
    sum_funcs_end[pos+1]= *func;

    /* Find the start of the group for this level */
    for (i= 0, start_group= group_list ;
	 i++ < pos ;
	 start_group= start_group->next)
      ;

    it.rewind();
    while ((item= it++))
    {
      if (item == first_field)
      {
	real_fields= 1;				// End of hidden fields
	ref_array= ref_array_start;
      }

      if (item->type() == Item::SUM_FUNC_ITEM && !item->const_item())
      {
	/*
	  This is a top level summary function that must be replaced with
	  a sum function that is reset for this level.

	  NOTE: This code creates an object which is not that nice in a
	  sub select.  Fortunately it's not common to have rollup in
	  sub selects.
	*/
	item= item->copy_or_same(thd);
	((Item_sum*) item)->make_unique();
	if (((Item_sum*) item)->setup(thd))
	  return 1;
	*(*func)= (Item_sum*) item;
	(*func)++;
      }
      else if (real_fields)
      {
	/* Check if this is something that is part of this group by */
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	ORDER *group_tmp;
	for (group_tmp= start_group ; group_tmp ; group_tmp= group_tmp->next)
8839
	{
8840
	  if (*group_tmp->item == item)
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	  {
	    /*
	      This is an element that is used by the GROUP BY and should be
	      set to NULL in this level
	    */
	    item->maybe_null= 1;		// Value will be null sometimes
	    item= rollup.item_null;
	    break;
	  }
	}
      }
      *ref_array= item;
      if (real_fields)
      {
	(void) new_it++;			// Point to next item
	new_it.replace(item);			// Replace previous
	ref_array++;
      }
      else
	ref_array--;
    }
  }
  sum_funcs_end[0]= *func;			// Point to last function
  return 0;
}

/*
  Send all rollup levels higher than the current one to the client

  SYNOPSIS:
    rollup_send_data()
    idx			Level we are on:
			0 = Total sum level
			1 = First group changed  (a)
			2 = Second group changed (a,b)

  SAMPLE
    SELECT a, b, c SUM(b) FROM t1 GROUP BY a,b WITH ROLLUP

  RETURN
    0	ok
    1   If send_data_failed()
*/

int JOIN::rollup_send_data(uint idx)
{
  uint i;
  for (i= send_group_parts ; i-- > idx ; )
  {
    /* Get reference pointers to sum functions in place */
    memcpy((char*) ref_pointer_array,
	   (char*) rollup.ref_pointer_arrays[i],
	   ref_pointer_array_size);
    if ((!having || having->val_int()))
    {
      if (send_records < unit->select_limit_cnt &&
	  result->send_data(rollup.fields[i]))
	return 1;
      send_records++;
    }
  }
  /* Restore ref_pointer_array */
  set_items_ref_array(current_ref_pointer_array);
  return 0;
}

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/*
  clear results if there are not rows found for group
  (end_send_group/end_write_group)

  SYNOPSYS
     JOIN::clear()
*/

void JOIN::clear()
{
  clear_tables(this);
  copy_fields(&tmp_table_param);

  if (sum_funcs)
  {
    Item_sum *func, **func_ptr= sum_funcs;
    while ((func= *(func_ptr++)))
      func->clear();
  }
}
8927

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/****************************************************************************
8929 8930
  EXPLAIN handling

8931
  Send a description about what how the select will be done to stdout
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****************************************************************************/

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static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
8935
			    bool distinct,const char *message)
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{
  List<Item> field_list;
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  List<Item> item_list;
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  THD *thd=join->thd;
8940
  SELECT_LEX *select_lex= &join->thd->lex->select_lex;
8941
  select_result *result=join->result;
8942
  Item *item_null= new Item_null();
8943
  CHARSET_INFO *cs= &my_charset_latin1;
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  DBUG_ENTER("select_describe");
8945
  DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s",
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		      (ulong)join->select_lex, join->select_lex->type,
8947
		      message ? message : "NULL"));
8948
  /* Don't log this into the slow query log */
8949
  thd->server_status&= ~(SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED);
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  join->unit->offset_limit_cnt= 0;
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8952
  if (message)
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  {
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    item_list.push_back(new Item_int((int32) join->select_lex->select_number));
    item_list.push_back(new Item_string(join->select_lex->type,
8956
					strlen(join->select_lex->type), cs));
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    for (uint i=0 ; i < 7; i++)
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      item_list.push_back(item_null);
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    item_list.push_back(new Item_string(message,strlen(message),cs));
8960
    if (result->send_data(item_list))
8961
      join->error= 1;
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  }
  else
  {
    table_map used_tables=0;
    for (uint i=0 ; i < join->tables ; i++)
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    {
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      JOIN_TAB *tab=join->join_tab+i;
      TABLE *table=tab->table;
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      char buff[512],*buff_ptr=buff;
8971
      char buff1[512], buff2[512];
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      char derived_name[64];
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      String tmp1(buff1,sizeof(buff1),cs);
      String tmp2(buff2,sizeof(buff2),cs);
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      tmp1.length(0);
      tmp2.length(0);

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      item_list.empty();
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      item_list.push_back(new Item_int((int32)
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				       join->select_lex->select_number));
      item_list.push_back(new Item_string(join->select_lex->type,
					  strlen(join->select_lex->type),
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					  cs));
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      if (tab->type == JT_ALL && tab->select && tab->select->quick)
	tab->type= JT_RANGE;
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      if (table->derived_select_number)
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      {
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	/* Derived table name generation */
	int len= my_snprintf(derived_name, sizeof(derived_name)-1,
			     "<derived%u>",
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			     table->derived_select_number);
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	item_list.push_back(new Item_string(derived_name, len, cs));
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      }
      else
	item_list.push_back(new Item_string(table->table_name,
					    strlen(table->table_name),
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					    cs));
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      item_list.push_back(new Item_string(join_type_str[tab->type],
					  strlen(join_type_str[tab->type]),
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					  cs));
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      uint j;
9002
      if (!tab->keys.is_clear_all())
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      {
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        for (j=0 ; j < table->keys ; j++)
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        {
          if (tab->keys.is_set(j))
          {
            if (tmp1.length())
              tmp1.append(',');
            tmp1.append(table->key_info[j].name);
          }
        }
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      }
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      if (tmp1.length())
9015
	item_list.push_back(new Item_string(tmp1.ptr(),tmp1.length(),cs));
9016
      else
9017
	item_list.push_back(item_null);
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      if (tab->ref.key_parts)
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      {
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	KEY *key_info=table->key_info+ tab->ref.key;
	item_list.push_back(new Item_string(key_info->name,
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					    strlen(key_info->name),
					    system_charset_info));
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	item_list.push_back(new Item_int((int32) tab->ref.key_length));
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	for (store_key **ref=tab->ref.key_copy ; *ref ; ref++)
	{
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	  if (tmp2.length())
	    tmp2.append(',');
	  tmp2.append((*ref)->name());
9030
	}
9031
	item_list.push_back(new Item_string(tmp2.ptr(),tmp2.length(),cs));
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      }
      else if (tab->type == JT_NEXT)
      {
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	KEY *key_info=table->key_info+ tab->index;
	item_list.push_back(new Item_string(key_info->name,
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					    strlen(key_info->name),cs));
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	item_list.push_back(new Item_int((int32) key_info->key_length));
	item_list.push_back(item_null);
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      }
      else if (tab->select && tab->select->quick)
      {
9043 9044
	KEY *key_info=table->key_info+ tab->select->quick->index;
	item_list.push_back(new Item_string(key_info->name,
9045
					    strlen(key_info->name),cs));
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	item_list.push_back(new Item_int((int32) tab->select->quick->
					 max_used_key_length));
9048
	item_list.push_back(item_null);
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      }
      else
      {
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	item_list.push_back(item_null);
	item_list.push_back(item_null);
	item_list.push_back(item_null);
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      }
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      item_list.push_back(new Item_int((longlong) (ulonglong)
				       join->best_positions[i]. records_read,
				       21));
9059
      my_bool key_read=table->key_read;
9060
      if (tab->type == JT_NEXT && table->used_keys.is_set(tab->index))
9061
	key_read=1;
9062

9063
      if (tab->info)
9064
	item_list.push_back(new Item_string(tab->info,strlen(tab->info),cs));
9065
      else
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9066
      {
9067
	if (tab->select)
9068
	{
9069 9070
	  if (tab->use_quick == 2)
	  {
9071
            char buf[MAX_KEY/8+1];
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9072
	    sprintf(buff_ptr,"; Range checked for each record (index map: 0x%s)",
9073
                tab->keys.print(buf));
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	    buff_ptr=strend(buff_ptr);
	  }
	  else
	    buff_ptr=strmov(buff_ptr,"; Using where");
9078
	}
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	if (key_read)
	  buff_ptr= strmov(buff_ptr,"; Using index");
	if (table->reginfo.not_exists_optimize)
	  buff_ptr= strmov(buff_ptr,"; Not exists");
	if (need_tmp_table)
	{
	  need_tmp_table=0;
	  buff_ptr= strmov(buff_ptr,"; Using temporary");
	}
	if (need_order)
	{
	  need_order=0;
	  buff_ptr= strmov(buff_ptr,"; Using filesort");
	}
9093
	if (distinct & test_all_bits(used_tables,thd->used_tables))
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	  buff_ptr= strmov(buff_ptr,"; Distinct");
	if (buff_ptr == buff)
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	  buff_ptr+= 2;				// Skip inital "; "
	item_list.push_back(new Item_string(buff+2,(uint) (buff_ptr - buff)-2,
9098
					    cs));
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      }
      // For next iteration
      used_tables|=table->map;
9102
      if (result->send_data(item_list))
9103
	join->error= 1;
9104
    }
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9105
  }
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  for (SELECT_LEX_UNIT *unit= join->select_lex->first_inner_unit();
       unit;
       unit= unit->next_unit())
  {
    if (mysql_explain_union(thd, unit, result))
      DBUG_VOID_RETURN;
  }
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9113 9114 9115
  DBUG_VOID_RETURN;
}

9116

9117 9118
int mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
{
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9119
  DBUG_ENTER("mysql_explain_union");
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  int res= 0;
  SELECT_LEX *first= unit->first_select();
  for (SELECT_LEX *sl= first;
       sl;
       sl= sl->next_select())
  {
9126 9127 9128
    // drop UNCACHEABLE_EXPLAIN, because it is for internal usage only
    uint8 uncacheable= (sl->uncacheable & ~UNCACHEABLE_EXPLAIN);

9129
    res= mysql_explain_select(thd, sl,
9130
			      (((&thd->lex->select_lex)==sl)?
9131 9132
			       ((thd->lex->all_selects_list != sl) ? 
				primary_key_name : "SIMPLE"):
9133
			       ((sl == first)?
9134 9135
				((sl->linkage == DERIVED_TABLE_TYPE) ?
				 "DERIVED":
9136
				((uncacheable & UNCACHEABLE_DEPENDENT) ?
9137
				 "DEPENDENT SUBQUERY":
9138
				 (uncacheable?"UNCACHEABLE SUBQUERY":
9139
				   "SUBQUERY"))):
9140
				((uncacheable & UNCACHEABLE_DEPENDENT) ?
9141
				 "DEPENDENT UNION":
9142
				 uncacheable?"UNCACHEABLE UNION":
9143
				  "UNION"))),
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			      result);
    if (res)
      break;

  }
9149 9150
  if (res > 0 || thd->net.report_error)
    res= -1; // mysql_explain_select do not report error
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9151
  DBUG_RETURN(res);
9152 9153
}

9154

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9155 9156
int mysql_explain_select(THD *thd, SELECT_LEX *select_lex, char const *type, 
			 select_result *result)
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9157
{
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9158 9159
  DBUG_ENTER("mysql_explain_select");
  DBUG_PRINT("info", ("Select 0x%lx, type %s", (ulong)select_lex, type))
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9160
  select_lex->type= type;
9161
  thd->lex->current_select= select_lex;
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9162
  SELECT_LEX_UNIT *unit=  select_lex->master_unit();
9163 9164 9165
  int res= mysql_select(thd, &select_lex->ref_pointer_array,
			(TABLE_LIST*) select_lex->table_list.first,
			select_lex->with_wild, select_lex->item_list,
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9166
			select_lex->where,
9167 9168
			select_lex->order_list.elements +
			select_lex->group_list.elements,
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9169 9170 9171
			(ORDER*) select_lex->order_list.first,
			(ORDER*) select_lex->group_list.first,
			select_lex->having,
9172
			(ORDER*) thd->lex->proc_list.first,
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9173
			select_lex->options | thd->options | SELECT_DESCRIBE,
9174
			result, unit, select_lex);
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9175
  DBUG_RETURN(res);
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9176
}
9177 9178 9179 9180 9181 9182 9183


void st_select_lex::print(THD *thd, String *str)
{
  if (!thd)
    thd= current_thd;

9184
  str->append("select ", 7);
9185 9186 9187
  
  //options
  if (options & SELECT_STRAIGHT_JOIN)
9188
    str->append("straight_join ", 14);
9189 9190
  if ((thd->lex->lock_option & TL_READ_HIGH_PRIORITY) &&
      (this == &thd->lex->select_lex))
9191
    str->append("high_priority ", 14);
9192
  if (options & SELECT_DISTINCT)
9193
    str->append("distinct ", 9);
9194
  if (options & SELECT_SMALL_RESULT)
9195
    str->append("small_result ", 13);
9196
  if (options & SELECT_BIG_RESULT)
9197
    str->append("big_result ", 11);
9198
  if (options & OPTION_BUFFER_RESULT)
9199
    str->append("buffer_result ", 14);
9200
  if (options & OPTION_FOUND_ROWS)
9201
    str->append("calc_found_rows ", 16);
9202
  if (!thd->lex->safe_to_cache_query)
9203
    str->append("no_cache ", 9);
9204
  if (options & OPTION_TO_QUERY_CACHE)
9205
    str->append("cache ", 6);
9206 9207 9208 9209 9210 9211 9212 9213 9214 9215 9216 9217 9218 9219 9220 9221 9222 9223 9224 9225

  //Item List
  bool first= 1;
  List_iterator_fast<Item> it(item_list);
  Item *item;
  while ((item= it++))
  {
    if (first)
      first= 0;
    else
      str->append(',');
    item->print_item_w_name(str);
  }

  /*
    from clause
    TODO: support USING/FORCE/IGNORE index
  */
  if (table_list.elements)
  {
9226
    str->append(" from ", 6);
9227 9228 9229 9230 9231 9232 9233 9234 9235 9236 9237 9238 9239 9240 9241 9242 9243 9244 9245 9246 9247 9248 9249 9250 9251 9252 9253 9254 9255 9256
    Item *next_on= 0;
    for (TABLE_LIST *table= (TABLE_LIST *) table_list.first;
	 table;
	 table= table->next)
    {
      if (table->derived)
      {
	str->append('(');
	table->derived->print(str);
	str->append(") ");
	str->append(table->alias);
      }
      else
      {
	str->append(table->db);
	str->append('.');
	str->append(table->real_name);
	if (strcmp(table->real_name, table->alias))
	{
	  str->append(' ');
	  str->append(table->alias);
	}
      }

      if (table->on_expr && ((table->outer_join & JOIN_TYPE_LEFT) ||
			     !(table->outer_join & JOIN_TYPE_RIGHT)))
	next_on= table->on_expr;

      if (next_on)
      {
9257
	str->append(" on(", 4);
9258 9259 9260 9261 9262
	next_on->print(str);
	str->append(')');
	next_on= 0;
      }

9263 9264
      TABLE_LIST *next_table;
      if ((next_table= table->next))
9265 9266 9267
      {
	if (table->outer_join & JOIN_TYPE_RIGHT)
	{
9268
	  str->append(" right join ", 12);
9269 9270 9271 9272
	  if (!(table->outer_join & JOIN_TYPE_LEFT) &&
	      table->on_expr)
	    next_on= table->on_expr;	    
	}
9273
	else if (next_table->straight)
9274
	  str->append(" straight_join ", 15);
9275
	else if (next_table->outer_join & JOIN_TYPE_LEFT)
9276
	  str->append(" left join ", 11);
9277
	else
9278
	  str->append(" join ", 6);
9279 9280 9281 9282
      }
    }
  }

9283 9284
  // Where
  Item *cur_where= where;
9285
  if (join)
9286 9287
    cur_where= join->conds;
  if (cur_where)
9288
  {
9289
    str->append(" where ", 7);
9290
    cur_where->print(str);
9291 9292
  }

9293
  // group by & olap
9294 9295
  if (group_list.elements)
  {
9296
    str->append(" group by ", 10);
9297 9298 9299 9300
    print_order(str, (ORDER *) group_list.first);
    switch (olap)
    {
      case CUBE_TYPE:
9301
	str->append(" with cube", 10);
9302 9303
	break;
      case ROLLUP_TYPE:
9304
	str->append(" with rollup", 12);
9305 9306 9307 9308 9309 9310
	break;
      default:
	;  //satisfy compiler
    }
  }

9311 9312
  // having
  Item *cur_having= having;
9313
  if (join)
9314
    cur_having= join->having;
9315

9316
  if (cur_having)
9317
  {
9318
    str->append(" having ", 8);
9319
    cur_having->print(str);
9320 9321 9322 9323
  }

  if (order_list.elements)
  {
9324
    str->append(" order by ", 10);
9325 9326 9327 9328 9329 9330 9331 9332
    print_order(str, (ORDER *) order_list.first);
  }

  // limit
  print_limit(thd, str);

  // PROCEDURE unsupported here
}