Desperate attempt to push part of prepared statements cleanup which was

reviewed in Saint-Petersbourg (including post-review fixes).


include/my_sys.h:
  Added clear_alloc_root (reset alloc root without freeing its memory)
sql/item.h:
  - rename setup_param -> set_parap (function assigns parameter value to item)
sql/mysql_priv.h:
  - all return values are void, because return value is never checked in
      dispatch_command
  - removed unused declaration of setup_param_functions
sql/protocol.h:
  - unused declarations of setup_params_data* removed
sql/sql_class.cc:
  Cleanup:
    - bzero(mem_root) replaced with clear_alloc_root
    - query_id and command members moved back to THD from Statement
  Assignment of mem_root, free_list, query_id and command optimized
  away from set_statement().
sql/sql_class.h:
  - query_id and command moved back to THD from Statement
sql/sql_lex.h:
  - better type for param_list
  - param_count is the same thing as param_list.elements
sql/sql_parse.cc:
  - comments for dispatch_command
sql/sql_prepare.cc:
  Cleanup:
  - added comments to many functions and removed trailing spaces in many 
    lines, some stale comments removed.
  - it's faster to iterate using pointers, than classes
  - Renames: error_in_prepare renamed to get_longdata_error (because it is set
    when there is an error in mysql_send_longdata, rather than in
    mysql_prepare), embedded versions of placeholder assignement functions
    now have prefix emb_, setup_ functions renamed to set_, because they
    perform assignment, not installation, setup_params_data now doesn't
    call insert_params and was renamed to setup_set_param_functions,
  - find_prepared_statement should not send error if called from no-reply
    calls, like mysql_stmt_reset
  - error reporting is checked up, to always report errors and not report
    errors twice. send_prep_stmt can be done mostly in send_prepare_result, 
    rather than in test_* functions.
  - now we don't need to reinit THD->mem_root/free_list in mysql_stmt_execute,
    because it's not reset there.
tests/client_test.c:
  - removed second call to test_subqueries

include/my_sys.h

@@ -714,6 +714,7 @@ extern void my_free_lock(byte *ptr,myf flags);
 #define my_free_lock(A,B) my_free((A),(B))
 #endif
 #define alloc_root_inited(A) ((A)->min_malloc != 0)
+#define clear_alloc_root(A) bzero((void *) (A), sizeof(MEM_ROOT))
 extern void init_alloc_root(MEM_ROOT *mem_root, uint block_size,
 			    uint pre_alloc_size);
 extern gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size);

sql/item.h

@@ -375,9 +375,9 @@ class Item_param :public Item
   bool get_time(TIME *tm);
   void reset() {}
 #ifndef EMBEDDED_LIBRARY
-  void (*setup_param_func)(Item_param *param, uchar **pos);
+  void (*set_param_func)(Item_param *param, uchar **pos);
 #else
-  void (*setup_param_func)(Item_param *param, uchar **pos, ulong data_len);
+  void (*set_param_func)(Item_param *param, uchar **pos, ulong data_len);
 #endif
   enum Item_result result_type () const
   { return item_result_type; }

sql/mysql_priv.h

@@ -620,14 +620,13 @@ int mysqld_show_column_types(THD *thd);
 int mysqld_help (THD *thd, const char *text);
 
 /* sql_prepare.cc */
-bool mysql_stmt_prepare(THD *thd, char *packet, uint packet_length);
+void mysql_stmt_prepare(THD *thd, char *packet, uint packet_length);
 void mysql_stmt_execute(THD *thd, char *packet);
 void mysql_stmt_free(THD *thd, char *packet);
 void mysql_stmt_reset(THD *thd, char *packet);
 void mysql_stmt_get_longdata(THD *thd, char *pos, ulong packet_length);
 int check_insert_fields(THD *thd,TABLE *table,List<Item> &fields,
 			List<Item> &values, ulong counter);
-void setup_param_functions(Item_param *param, uchar param_type);
 
 /* sql_error.cc */
 MYSQL_ERROR *push_warning(THD *thd, MYSQL_ERROR::enum_warning_level level, uint code,

sql/protocol.h

@@ -178,8 +178,3 @@ char *net_store_data(char *to,const char *from, uint length);
 char *net_store_data(char *to,int32 from);
 char *net_store_data(char *to,longlong from);
 
-#ifdef EMBEDDED_LIBRARY
-bool setup_params_data(struct st_prep_stmt *stmt);
-bool setup_params_data_withlog(struct st_prep_stmt *stmt);
-#endif
-

sql/sql_class.cc

@@ -145,8 +145,7 @@ THD::THD():user_time(0), current_statement(0), is_fatal_error(0),
 
   init();
   /* Initialize sub structures */
-  bzero((char*) &transaction.mem_root,sizeof(transaction.mem_root));
-  bzero((char*) &warn_root,sizeof(warn_root));
+  clear_alloc_root(&transaction.mem_root);
   init_alloc_root(&warn_root, WARN_ALLOC_BLOCK_SIZE, WARN_ALLOC_PREALLOC_SIZE);
   user_connect=(USER_CONN *)0;
   hash_init(&user_vars, &my_charset_bin, USER_VARS_HASH_SIZE, 0, 0,
@@ -331,7 +330,7 @@ THD::~THD()
   dbug_sentry = THD_SENTRY_GONE;
 #endif  
   /* Reset stmt_backup.mem_root to not double-free memory from thd.mem_root */
-  init_alloc_root(&stmt_backup.mem_root, 0, 0);
+  clear_alloc_root(&stmt_backup.mem_root);
   DBUG_VOID_RETURN;
 }
 
@@ -1185,10 +1184,8 @@ int select_dumpvar::prepare(List<Item> &list, SELECT_LEX_UNIT *u)
 
 Statement::Statement(THD *thd)
   :id(++thd->statement_id_counter),
-  query_id(thd->query_id),
   set_query_id(1),
   allow_sum_func(0),
-  command(thd->command),
   lex(&main_lex),
   query(0),
   query_length(0),
@@ -1207,10 +1204,8 @@ Statement::Statement(THD *thd)
 
 Statement::Statement()
   :id(0),
-  query_id(0),                                  /* initialized later */
   set_query_id(1),
   allow_sum_func(0),                            /* initialized later */
-  command(COM_SLEEP),                           /* initialized later */ 
   lex(&main_lex),
   query(0),                                     /* these two are set */ 
   query_length(0),                              /* in alloc_query() */
@@ -1229,15 +1224,11 @@ Statement::Type Statement::type() const
 void Statement::set_statement(Statement *stmt)
 {
   id=             stmt->id;
-  query_id=       stmt->query_id;
   set_query_id=   stmt->set_query_id;
   allow_sum_func= stmt->allow_sum_func;
-  command=        stmt->command;
   lex=            stmt->lex;
   query=          stmt->query;
   query_length=   stmt->query_length;
-  free_list=      stmt->free_list;
-  mem_root=       stmt->mem_root;
 }
 
 

sql/sql_class.h

@@ -434,15 +434,6 @@ class Statement
   */
    ulong id;
 
-  /*
-    Id of current query. Statement can be reused to execute several queries
-    query_id is global in context of the whole MySQL server.
-    ID is automatically generated from mutex-protected counter.
-    It's used in handler code for various purposes: to check which columns
-    from table are necessary for this select, to check if it's necessary to
-    update auto-updatable fields (like auto_increment and timestamp).
-  */
-  ulong query_id;
   /*
     - if set_query_id=1, we set field->query_id for all fields. In that case 
     field list can not contain duplicates.
@@ -461,11 +452,6 @@ class Statement
     See item_sum.cc for details.
   */
   bool allow_sum_func;
-  /*
-    Type of current query: COM_PREPARE, COM_QUERY, etc. Set from 
-    first byte of the packet in do_command()
-  */
-  enum enum_server_command command;
 
   LEX *lex;                                     // parse tree descriptor
   /*
@@ -676,6 +662,11 @@ class THD :public ilink,
   uint dbug_sentry; // watch out for memory corruption
 #endif
   struct st_my_thread_var *mysys_var;
+  /*
+    Type of current query: COM_PREPARE, COM_QUERY, etc. Set from 
+    first byte of the packet in do_command()
+  */
+  enum enum_server_command command;
   uint32     server_id;
   uint32     file_id;			// for LOAD DATA INFILE
   /*
@@ -751,6 +742,15 @@ class THD :public ilink,
   List	     <MYSQL_ERROR> warn_list;
   uint	     warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
   uint	     total_warn_count;
+  /*
+    Id of current query. Statement can be reused to execute several queries
+    query_id is global in context of the whole MySQL server.
+    ID is automatically generated from mutex-protected counter.
+    It's used in handler code for various purposes: to check which columns
+    from table are necessary for this select, to check if it's necessary to
+    update auto-updatable fields (like auto_increment and timestamp).
+  */
+  ulong	     query_id;
   ulong	     warn_id, version, options, thread_id, col_access;
 
   /* Statement id is thread-wide. This counter is used to generate ids */

sql/sql_lex.h

@@ -552,7 +552,7 @@ typedef struct st_lex
   List<Item>	      *insert_list,field_list,value_list;
   List<List_item>     many_values;
   List<set_var_base>  var_list;
-  List<Item>          param_list;
+  List<Item_param>    param_list;
   SQL_LIST	      proc_list, auxilliary_table_list, save_list;
   TYPELIB	      *interval;
   create_field	      *last_field;
@@ -577,7 +577,6 @@ typedef struct st_lex
   uint uint_geom_type;
   uint grant, grant_tot_col, which_columns;
   uint fk_delete_opt, fk_update_opt, fk_match_option;
-  uint param_count;
   uint slave_thd_opt;
   uint8 describe;
   bool drop_if_exists, drop_temporary, local_file;

sql/sql_parse.cc

@@ -1232,10 +1232,34 @@ bool do_command(THD *thd)
 		       command_name[command]));
   }
   net->read_timeout=old_timeout;		// restore it
+  /*
+    packet_length contains length of data, as it was stored in packet
+    header. In case of malformed header, packet_length can be zero.
+    If packet_length is not zero, my_net_read ensures that this number
+    of bytes was actually read from network. Additionally my_net_read
+    sets packet[packet_length]= 0 (thus if packet_length == 0,
+    command == packet[0] == COM_SLEEP).
+    In dispatch_command packet[packet_length] points beyond the end of packet.
+  */
   DBUG_RETURN(dispatch_command(command,thd, packet+1, (uint) packet_length));
 }
 #endif  /* EMBEDDED_LIBRARY */
 
+/*
+   Perform one connection-level (COM_XXXX) command.
+  SYNOPSIS
+    dispatch_command()
+    thd             connection handle
+    command         type of command to perform 
+    packet          data for the command, packet is always null-terminated
+    packet_length   length of packet + 1 (to show that data is
+                    null-terminated) except for COM_SLEEP, where it
+                    can be zero.
+  RETURN VALUE
+    0   ok
+    1   request of thread shutdown, i. e. if command is
+        COM_QUIT/COM_SHUTDOWN
+*/
 
 bool dispatch_command(enum enum_server_command command, THD *thd,
 		      char* packet, uint packet_length)

sql/sql_yacc.yy

@@ -4478,11 +4478,17 @@ text_string:
 param_marker:
         '?'
         {
-	  LEX *lex=Lex;
-          if (YYTHD->command == COM_PREPARE)
+          THD *thd=YYTHD;
+	  LEX *lex= thd->lex;
+          if (thd->command == COM_PREPARE)
           {
-            lex->param_list.push_back($$=new Item_param((uint)(lex->tok_start-(uchar *)YYTHD->query)));
-            lex->param_count++;
+            Item_param *item= new Item_param((uint) (lex->tok_start -
+                                                     (uchar *) thd->query));
+            if (!($$= item) || lex->param_list.push_back(item))
+            {
+	      send_error(thd, ER_OUT_OF_RESOURCES);
+	      YYABORT;
+            }
           }
           else
           {

tests/client_test.c

@@ -8470,8 +8470,6 @@ int main(int argc, char **argv)
    
     start_time= time((time_t *)0);
 
-    test_subqueries();
-
     client_query();         /* simple client query test */
 #if NOT_YET_WORKING
     /* Used for internal new development debugging */