ulternative bugfix for BUG#2508 and fix for BUG#2809 - every table has its own TABLE structure

mysql-test/r/union.result:
  fix for union test becuase now not all fields in UNION allow NULLS
  fix of test
  test suite for BUG#2809
mysql-test/t/union.test:
  test suite for BUG#2809
sql/mysql_priv.h:
  removed unused parameter of setup_tables()
sql/sql_base.cc:
  removed unused parameter of setup_tables()
  cleanup of unused code
sql/sql_class.h:
  removed unused field
sql/sql_help.cc:
  removed unused parameter of setup_tables()
sql/sql_insert.cc:
  removed unused parameter of setup_tables()
sql/sql_lex.cc:
  excluded duplicate tables finding for UNION
sql/sql_load.cc:
  removed unused parameter of setup_tables()
sql/sql_olap.cc:
  removed unused parameter of setup_tables()
sql/sql_prepare.cc:
  removed unused parameter of setup_tables()
sql/sql_select.cc:
  removed unused parameter of setup_tables()
  revert old BUG#2508 patch
sql/sql_union.cc:
  revert old BUG#2508 patch
  removed unused code
sql/sql_update.cc:
  removed unused parameter of setup_tables()
sql/table.h:
  shared used only for multi-update for now

mysql-test/r/union.result

@@ -539,7 +539,7 @@ aa
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` char(2) default NULL
+  `a` char(2) NOT NULL default ''
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT 12 as a UNION select "aa" as a;
@@ -550,7 +550,7 @@ aa
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` char(2) default NULL
+  `a` char(2) NOT NULL default ''
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT 12 as a UNION select 12.2 as a;
@@ -561,7 +561,7 @@ a
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` double(4,1) default NULL
+  `a` double(4,1) NOT NULL default '0.0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t2 (it1 tinyint, it2 tinyint not null, i int not null, ib bigint, f float, d double, y year, da date, dt datetime, sc char(10), sv varchar(10), b blob, tx text);
@@ -585,7 +585,7 @@ it2
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `it2` int(11) default NULL
+  `it2` int(11) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT i from t2 UNION select f from t2;
@@ -799,7 +799,7 @@ select * from t1;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `1` bigint(1) default NULL
+  `1` bigint(1) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 select _latin1"test" union select _latin2"testt" ;
@@ -808,7 +808,7 @@ create table t1 select _latin2"test" union select _latin2"testt" ;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `test` char(5) character set latin2 default NULL
+  `test` char(5) character set latin2 NOT NULL default ''
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 (s char(200));
@@ -856,7 +856,7 @@ Variable_name	Value
 Slow_queries	1
 select count(*) from t1 where b=13 union select count(*) from t1 where a=7;
 count(*)
-0
+10
 26
 show status like 'Slow_queries';
 Variable_name	Value
@@ -893,3 +893,31 @@ third
 2
 3
 drop table t1;
+create table t1 (col1 tinyint unsigned, col2 tinyint unsigned);
+insert into t1 values (1,2),(3,4),(5,6),(7,8),(9,10);
+select col1 n from t1 union select col2 n from t1 order by n;
+n
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+alter table t1 add index myindex (col2);
+select col1 n from t1 union select col2 n from t1 order by n;
+n
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+drop  table t1;

mysql-test/t/union.test

@@ -484,3 +484,13 @@ insert into t1 values(1,'first','fff'),(2,'second','sss'),(3,'third','ttt');
 select name2 from t1  union all  select name from t1 union all select id from t1;
 drop table t1;
 
+#
+# Bug #2809 (UNION fails on MyIsam tables when index on second column from
+# same table)
+#
+create table t1 (col1 tinyint unsigned, col2 tinyint unsigned);
+insert into t1 values (1,2),(3,4),(5,6),(7,8),(9,10);
+select col1 n from t1 union select col2 n from t1 order by n;
+alter table t1 add index myindex (col2);
+select col1 n from t1 union select col2 n from t1 order by n;
+drop  table t1;

sql/mysql_priv.h

@@ -665,7 +665,7 @@ bool get_key_map_from_key_list(key_map *map, TABLE *table,
 bool insert_fields(THD *thd,TABLE_LIST *tables,
 		   const char *db_name, const char *table_name,
 		   List_iterator<Item> *it);
-bool setup_tables(TABLE_LIST *tables, my_bool reinit);
+bool setup_tables(TABLE_LIST *tables);
 int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
 	       List<Item> *sum_func_list, uint wild_num);
 int setup_fields(THD *thd, Item** ref_pointer_array, TABLE_LIST *tables,

sql/sql_base.cc

@@ -2106,8 +2106,6 @@ int setup_fields(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
   SYNOPSIS
     setup_tables()
     tables - tables list
-    reinit - true if called for table reinitialization before
-             subquery reexecuting
 
    RETURN
      0	ok;  In this case *map will includes the choosed index
@@ -2122,7 +2120,7 @@ int setup_fields(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
      table->map is not set and all Item_field will be regarded as const items.
 */
 
-bool setup_tables(TABLE_LIST *tables, my_bool reinit)
+bool setup_tables(TABLE_LIST *tables)
 {
   DBUG_ENTER("setup_tables");
   uint tablenr=0;
@@ -2149,13 +2147,6 @@ bool setup_tables(TABLE_LIST *tables, my_bool reinit)
       table->keys_in_use_for_query.subtract(map);
     }
     table->used_keys.intersect(table->keys_in_use_for_query);
-    if ((table_list->shared  || table->clear_query_id) && !reinit)
-    {
-      table->clear_query_id= 0;
-      /* Clear query_id that may have been set by previous select */
-      for (Field **ptr=table->field ; *ptr ; ptr++)
-	(*ptr)->query_id=0;
-    }
   }
   if (tablenr > MAX_TABLES)
   {

sql/sql_class.h

@@ -1076,11 +1076,11 @@ class TMP_TABLE_PARAM :public Sql_alloc
   uint  hidden_field_count;
   uint	group_parts,group_length,group_null_parts;
   uint	quick_group;
-  bool  using_indirect_summary_function, all_nulls;
+  bool  using_indirect_summary_function;
 
   TMP_TABLE_PARAM()
     :copy_funcs_it(copy_funcs), copy_field(0), group_parts(0),
-    group_length(0), group_null_parts(0), all_nulls(0)
+    group_length(0), group_null_parts(0)
   {}
   ~TMP_TABLE_PARAM()
   {

sql/sql_help.cc

@@ -686,7 +686,7 @@ int mysqld_help(THD *thd, const char *mask)
     goto end;
   }
   /* Init tables and fields to be usable from items */
-  setup_tables(tables, 0);
+  setup_tables(tables);
   memcpy((char*) used_fields, (char*) init_used_fields, sizeof(used_fields)); 
   if (init_fields(thd, tables, used_fields, array_elements(used_fields)))
   {

sql/sql_insert.cc

@@ -84,7 +84,7 @@ check_insert_fields(THD *thd,TABLE *table,List<Item> &fields,
     table_list.grant=table->grant;
 
     thd->dupp_field=0;
-    if (setup_tables(&table_list, 0) ||
+    if (setup_tables(&table_list) ||
 	setup_fields(thd, 0, &table_list,fields,1,0,0))
       return -1;
     if (thd->dupp_field)
@@ -204,7 +204,7 @@ int mysql_insert(THD *thd,TABLE_LIST *table_list,
   }
 
   if (check_insert_fields(thd,table,fields,*values,1) ||
-      setup_tables(insert_table_list, 0) ||
+      setup_tables(insert_table_list) ||
       setup_fields(thd, 0, insert_table_list, *values, 0, 0, 0) ||
       (duplic == DUP_UPDATE &&
        (setup_fields(thd, 0, insert_table_list, update_fields, 0, 0, 0) ||

sql/sql_lex.cc

@@ -1376,13 +1376,6 @@ create_total_list_n_last_return(THD *thd_arg,
       {
 	TABLE_LIST *cursor;
 	next_table= aux->next;
-	for (cursor= **result_arg; cursor; cursor= cursor->next)
-	  if (!strcmp(cursor->db, aux->db) &&
-	      !strcmp(cursor->real_name, aux->real_name) &&
-	      !strcmp(cursor->alias, aux->alias))
-	    break;
-	if (!cursor)
-	{
 	/* Add not used table to the total table list */
 	if (!(cursor= (TABLE_LIST *) thd->memdup((char*) aux,
 						 sizeof(*aux))))
@@ -1391,13 +1384,9 @@ create_total_list_n_last_return(THD *thd_arg,
 	  return 1;
 	}
 	*new_table_list= cursor;
-	  cursor->table_list= aux; //to be able mark this table as shared
+	cursor->table_list= aux;
 	new_table_list= &cursor->next;
 	*new_table_list= 0;			// end result list
-	}
-	else
-	  // Mark that it's used twice
-	  cursor->table_list->shared= aux->shared= 1;
 	aux->table_list= cursor;
       }
     }

sql/sql_load.cc

@@ -123,7 +123,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   else
   {						// Part field list
     thd->dupp_field=0;
-    if (setup_tables(table_list, 0) ||
+    if (setup_tables(table_list) ||
 	setup_fields(thd, 0, table_list, fields, 1, 0, 0))
       DBUG_RETURN(-1);
     if (thd->dupp_field)

sql/sql_olap.cc

@@ -152,7 +152,7 @@ int handle_olaps(LEX *lex, SELECT_LEX *select_lex)
   List<Item>	all_fields(select_lex->item_list);
 
 
-  if (setup_tables((TABLE_LIST *)select_lex->table_list.first, 0) ||
+  if (setup_tables((TABLE_LIST *)select_lex->table_list.first) ||
       setup_fields(lex->thd, 0, (TABLE_LIST *)select_lex->table_list.first,
 		   select_lex->item_list, 1, &all_fields,1) ||
       setup_fields(lex->thd, 0, (TABLE_LIST *)select_lex->table_list.first,

sql/sql_prepare.cc

@@ -679,7 +679,7 @@ static bool mysql_test_upd_fields(Prepared_statement *stmt,
 #endif
   if (open_and_lock_tables(thd, table_list))
     DBUG_RETURN(1);
-  if (setup_tables(table_list, 0) ||
+  if (setup_tables(table_list) ||
       setup_fields(thd, 0, table_list, fields, 1, 0, 0) || 
       setup_conds(thd, table_list, &conds) || thd->net.report_error)      
     DBUG_RETURN(1);

sql/sql_select.cc

@@ -298,7 +298,7 @@ JOIN::prepare(Item ***rref_pointer_array,
 
   /* Check that all tables, fields, conds and order are ok */
 
-  if (setup_tables(tables_list, 0) ||
+  if (setup_tables(tables_list) ||
       setup_wild(thd, tables_list, fields_list, &all_fields, wild_num) ||
       select_lex->setup_ref_array(thd, og_num) ||
       setup_fields(thd, (*rref_pointer_array), tables_list, fields_list, 1,
@@ -1014,7 +1014,7 @@ JOIN::reinit()
   if (unit->select_limit_cnt == HA_POS_ERROR)
     select_lex->options&= ~OPTION_FOUND_ROWS;
   
-  if (setup_tables(tables_list, 1))
+  if (setup_tables(tables_list))
     DBUG_RETURN(1);
   
   /* Reset of sum functions */
@@ -4964,8 +4964,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 			     tmp_from_field, group != 0,not_all_columns);
 	  if (!new_field)
 	    goto err;					// Should be OOM
-	  if (param->all_nulls)
-	    new_field->flags&= ~NOT_NULL_FLAG;	// Because of outer join
 	  tmp_from_field++;
 	  *(reg_field++)= new_field;
 	  reclength+=new_field->pack_length();
@@ -5001,8 +4999,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 	  goto err;				// Got OOM
 	continue;				// Some kindf of const item
       }
-      if (param->all_nulls)
-	new_field->flags&= ~NOT_NULL_FLAG;	// Because of outer join
       if (type == Item::SUM_FUNC_ITEM)
 	((Item_sum *) item)->result_field= new_field;
       tmp_from_field++;

sql/sql_union.cc

@@ -206,7 +206,6 @@ int st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result,
   if (first_select->next_select())
   {
     union_result->tmp_table_param.field_count= types.elements;
-    union_result->tmp_table_param.all_nulls= true;
     if (!(table= create_tmp_table(thd_arg,
 				  &union_result->tmp_table_param, types,
 				  (ORDER*) 0, !union_option, 1, 
@@ -310,30 +309,6 @@ int st_select_lex_unit::exec()
 	  sl->options|= found_rows_for_union;
 	}
 	sl->join->select_options=sl->options;
-	/*
-	  As far as union share table space we should reassign table map,
-	  which can be spoiled by 'prepare' of JOIN of other UNION parts
-	  if it use same tables
-	*/
-	uint tablenr=0;
-	ulong query_id= thd->query_id;
-	for (TABLE_LIST *table_list= (TABLE_LIST*) sl->table_list.first;
-	     table_list;
-	     table_list= table_list->next, tablenr++)
-	{
-	  if (table_list->shared)
-	  {
-	    /*
-	      review notes: Check it carefully. I still can't understand
-	      why I should not touch table->used_keys. For my point of
-	      view we should do here same procedura as it was done by
-	      setup_table
-	    */
-	    setup_table_map(table_list->table, table_list, tablenr);
-	  }
-	  for (unsigned int i=0; i < table_list->table->fields; i++)
-	    table_list->table->field[i]->query_id= query_id;
-	}
 	res= sl->join->optimize();
       }
       if (!res)

sql/sql_update.cc

@@ -94,7 +94,7 @@ int mysql_update(THD *thd,
   tables.table= table;
   tables.alias= table_list->alias;
 
-  if (setup_tables(update_table_list, 0) ||
+  if (setup_tables(update_table_list) ||
       setup_conds(thd,update_table_list,&conds) ||
       thd->lex->select_lex.setup_ref_array(thd, order_num) ||
       setup_order(thd, thd->lex->select_lex.ref_pointer_array,

sql/table.h

@@ -173,7 +173,7 @@ typedef struct st_table_list
  GRANT_INFO	grant;
   thr_lock_type lock_type;
   uint		outer_join;		/* Which join type */
-  uint		shared;			/* Used in union or in multi-upd */
+  uint		shared;			/* Used in multi-upd */
   uint32        db_length, real_name_length;
   bool		straight;		/* optimize with prev table */
   bool          updating;               /* for replicate-do/ignore table */