merge

sql/item.cc

@@ -969,8 +969,10 @@ bool Item_field::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
 
 void Item_field::cleanup()
 {
+  DBUG_ENTER("Item_field::cleanup");
   Item_ident::cleanup();
   field= result_field= 0;
+  DBUG_VOID_RETURN;
 }
 
 void Item::init_make_field(Send_field *tmp_field,
@@ -1613,9 +1615,11 @@ bool Item_ref::fix_fields(THD *thd,TABLE_LIST *tables, Item **reference)
 
 void Item_ref::cleanup()
 {
+  DBUG_ENTER("Item_ref::cleanup");
   Item_ident::cleanup();
   if (hook_ptr)
     *hook_ptr= orig_item;
+  DBUG_VOID_RETURN;
 }
 
 

sql/item.h

@@ -128,7 +128,13 @@ class Item {
   virtual ~Item() { name=0; }		/*lint -e1509 */
   void set_name(const char *str,uint length, CHARSET_INFO *cs);
   void init_make_field(Send_field *tmp_field,enum enum_field_types type);
-  virtual void cleanup() { fixed=0; }
+  virtual void cleanup()
+  {
+    DBUG_ENTER("Item::cleanup");
+    DBUG_PRINT("info", ("Type: %d", (int)type()));
+    fixed=0;
+    DBUG_VOID_RETURN;
+  }
   virtual void make_field(Send_field *field);
   virtual bool fix_fields(THD *, struct st_table_list *, Item **);
   virtual int save_in_field(Field *field, bool no_conversions);
@@ -413,6 +419,7 @@ class Item_int :public Item
   int save_in_field(Field *field, bool no_conversions);
   bool basic_const_item() const { return 1; }
   Item *new_item() { return new Item_int(name,value,max_length); }
+  void cleanup() { fixed= 1; } // to privent drop fixed flag
   void print(String *str);
 };
 
@@ -900,6 +907,8 @@ class Item_cache: public Item
   enum Type type() const { return CACHE_ITEM; }
   static Item_cache* get_cache(Item_result type);
   table_map used_tables() const { return used_table_map; }
+  virtual void keep_array() {}
+  void cleanup() { fixed= 1; } // to privent drop fixed flag
   void print(String *str);
 };
 
@@ -952,8 +961,10 @@ class Item_cache_row: public Item_cache
 {
   Item_cache  **values;
   uint item_count;
+  bool save_array;
 public:
-  Item_cache_row(): Item_cache(), values(0), item_count(2) {}
+  Item_cache_row()
+    :Item_cache(), values(0), item_count(2), save_array(0) {}
   
   /*
     'allocate' used only in row transformer, to preallocate space for row 
@@ -994,10 +1005,16 @@ class Item_cache_row: public Item_cache
   bool check_cols(uint c);
   bool null_inside();
   void bring_value();
+  void keep_array() { save_array= 1; }
   void cleanup()
   {
+    DBUG_ENTER("Item_cache_row::cleanup");
     Item_cache::cleanup();
+    if (save_array)
+      bzero(values, item_count*sizeof(Item**));
+    else
       values= 0;
+    DBUG_VOID_RETURN;
   }
 };
 
@@ -1023,8 +1040,10 @@ class Item_type_holder: public Item
   Field *example() { return field_example; }
   void cleanup()
   {
+    DBUG_ENTER("Item_type_holder::cleanup");
     Item::cleanup();
     item_type= orig_type;
+    DBUG_VOID_RETURN;
   }
 };
 

sql/item_cmpfunc.cc

@@ -500,7 +500,6 @@ bool Item_in_optimizer::fix_left(THD *thd,
 }
 
 
-
 bool Item_in_optimizer::fix_fields(THD *thd, struct st_table_list *tables,
 				   Item ** ref)
 {
@@ -526,6 +525,7 @@ bool Item_in_optimizer::fix_fields(THD *thd, struct st_table_list *tables,
   return 0;
 }
 
+
 longlong Item_in_optimizer::val_int()
 {
   cache->store(args[0]);
@@ -539,18 +539,38 @@ longlong Item_in_optimizer::val_int()
   return tmp;
 }
 
+
+void Item_in_optimizer::keep_top_level_cache()
+{
+  cache->keep_array();
+  save_cache= 1;
+}
+
+
+void Item_in_optimizer::cleanup()
+{
+  DBUG_ENTER("Item_in_optimizer::cleanup");
+  Item_bool_func::cleanup();
+  if (!save_cache)
+    cache= 0;
+  DBUG_VOID_RETURN;
+}
+
+
 bool Item_in_optimizer::is_null()
 {
   cache->store(args[0]);
   return (null_value= (cache->null_value || args[1]->is_null()));
 }
 
+
 longlong Item_func_eq::val_int()
 {
   int value= cmp.compare();
   return value == 0 ? 1 : 0;
 }
 
+
 /* Same as Item_func_eq, but NULL = NULL */
 
 void Item_func_equal::fix_length_and_dec()

sql/item_cmpfunc.h

@@ -93,9 +93,10 @@ class Item_in_optimizer: public Item_bool_func
 {
 protected:
   Item_cache *cache;
+  bool save_cache;
 public:
   Item_in_optimizer(Item *a, Item_in_subselect *b):
-    Item_bool_func(a, (Item *)b), cache(0) {}
+    Item_bool_func(a, (Item *)b), cache(0), save_cache(0) {}
   bool fix_fields(THD *, struct st_table_list *, Item **);
   bool fix_left(THD *thd, struct st_table_list *tables, Item **ref);
   bool is_null();
@@ -107,8 +108,10 @@ class Item_in_optimizer: public Item_bool_func
     Item_in_optimizer return NULL, else it evaluate Item_in_subselect.
   */
   longlong val_int();
+  void cleanup();
   const char *func_name() const { return "<in_optimizer>"; }
   Item_cache **get_cache() { return &cache; }
+  void keep_top_level_cache();
 };
 
 class Comp_creator
@@ -209,9 +212,11 @@ class Item_bool_rowready_func2 :public Item_bool_func2
   }
   void cleanup()
   {
+    DBUG_ENTER("Item_bool_rowready_func2::cleanup");
     Item_bool_func2::cleanup();
     tmp_arg[0]= orig_a;
     tmp_arg[1]= orig_b;
+    DBUG_VOID_RETURN;
   }
 };
 
@@ -720,10 +725,12 @@ class Item_func_in :public Item_int_func
   void fix_length_and_dec();
   void cleanup()
   {
+    DBUG_ENTER("Item_func_in::cleanup");
     delete array;
     delete in_item;
     array= 0;
     in_item= 0;
+    DBUG_VOID_RETURN;
   }
   optimize_type select_optimize() const
     { return array ? OPTIMIZE_KEY : OPTIMIZE_NONE; }

sql/item_func.h

@@ -999,6 +999,7 @@ class Item_func_match :public Item_real_func
        join_key(0), ft_handler(0), table(0), master(0), concat(0) { }
   void cleanup()
   {
+    DBUG_ENTER("Item_func_match");
     if (!master && ft_handler)
     {
       ft_handler->please->close_search(ft_handler);
@@ -1009,6 +1010,7 @@ class Item_func_match :public Item_real_func
     }
     if (concat)
       delete concat;
+    DBUG_VOID_RETURN;
   }
   enum Functype functype() const { return FT_FUNC; }
   const char *func_name() const { return "match"; }

sql/item_subselect.h

@@ -26,6 +26,7 @@ class JOIN;
 class select_subselect;
 class subselect_engine;
 class Item_bool_func2;
+class Statement;
 
 /* base class for subselects */
 
@@ -35,22 +36,30 @@ class Item_subselect :public Item_result_field
 protected:
   /* thread handler, will be assigned in fix_fields only */
   THD *thd;
+  /* prepared statement, or 0 */
+  Statement *stmt;
   /* substitution instead of subselect in case of optimization */
   Item *substitution;
+  /* unit of subquery */
+  st_select_lex_unit *unit;
   /* engine that perform execution of subselect (single select or union) */
   subselect_engine *engine;
+  /* old engine if engine was changed */
+  subselect_engine *old_engine;
   /* cache of used external tables */
   table_map used_tables_cache; 
   /* allowed number of columns (1 for single value subqueries) */
   uint max_columns;
   /* work with 'substitution' */
   bool have_to_be_excluded;
-  /* cache of constante state */
+  /* cache of constant state */
   bool const_item_cache;
 
 public:
   /* changed engine indicator */
   bool engine_changed;
+  /* subquery is transformed */
+  bool changed;
 
   enum trans_res {RES_OK, RES_REDUCE, RES_ERROR};
   enum subs_type {UNKNOWN_SUBS, SINGLEROW_SUBS,
@@ -94,6 +103,7 @@ class Item_subselect :public Item_result_field
   void print(String *str);
   bool change_engine(subselect_engine *eng)
   {
+    old_engine= engine;
     engine= eng;
     engine_changed= 1;
     return eng == 0;
@@ -116,6 +126,7 @@ class Item_singlerow_subselect :public Item_subselect
   Item_singlerow_subselect(st_select_lex *select_lex);
   Item_singlerow_subselect() :Item_subselect(), value(0), row (0) {}
 
+  void cleanup();
   subs_type substype() { return SINGLEROW_SUBS; }
 
   void reset();
@@ -200,13 +211,6 @@ class Item_in_subselect :public Item_exists_subselect
      
   {}
 
-  void cleanup()
-  {
-    Item_exists_subselect::cleanup();
-    abort_on_null= 0;
-    transformed= 0;
-    upper_not= 0;
-  }
   subs_type substype() { return IN_SUBS; }
   void reset() 
   {
@@ -269,7 +273,7 @@ class subselect_engine: public Sql_alloc
     maybe_null= 0;
   }
   virtual ~subselect_engine() {}; // to satisfy compiler
-  virtual void cleanup() {}
+  virtual void cleanup()= 0;
   
   // set_thd should be called before prepare()
   void set_thd(THD *thd_arg) { thd= thd_arg; }
@@ -318,6 +322,7 @@ class subselect_union_engine: public subselect_engine
   subselect_union_engine(st_select_lex_unit *u,
 			 select_subselect *result,
 			 Item_subselect *item);
+  void cleanup();
   int prepare();
   void fix_length_and_dec(Item_cache** row);
   int exec();
@@ -345,6 +350,7 @@ class subselect_uniquesubquery_engine: public subselect_engine
     set_thd(thd_arg);
   }
   ~subselect_uniquesubquery_engine();
+  void cleanup();
   int prepare();
   void fix_length_and_dec(Item_cache** row);
   int exec();

sql/item_sum.cc

@@ -1084,6 +1084,7 @@ int dump_leaf(byte* key, uint32 count __attribute__((unused)),
 
 void Item_sum_count_distinct::cleanup()
 {
+  DBUG_ENTER("Item_sum_count_distinct::cleanup");
   Item_sum_int::cleanup();
   /*
     Free table and tree if they belong to this item (if item have not pointer
@@ -1104,6 +1105,7 @@ void Item_sum_count_distinct::cleanup()
       use_tree= 0;
     }
   }
+  DBUG_VOID_RETURN;
 }
 
 
@@ -1672,6 +1674,7 @@ Item_func_group_concat::Item_func_group_concat(bool is_distinct,
 
 void Item_func_group_concat::cleanup()
 {
+  DBUG_ENTER("Item_func_group_concat::cleanup");
   /*
     Free table and tree if they belong to this item (if item have not pointer
     to original item from which was made copy => it own its objects )
@@ -1692,6 +1695,7 @@ void Item_func_group_concat::cleanup()
       delete_tree(tree); 
     }
   }
+  DBUG_VOID_RETURN;
 }
 
 

sql/item_sum.h

@@ -60,8 +60,10 @@ class Item_sum :public Item_result_field
   Item_sum(THD *thd, Item_sum *item);
   void cleanup()
   {
+    DBUG_ENTER("Item_sum::cleanup");
     Item_result_field::cleanup();
     result_field=0;
+    DBUG_VOID_RETURN;
   }
 
   enum Type type() const { return SUM_FUNC_ITEM; }

sql/mysql_priv.h

@@ -350,6 +350,11 @@ inline THD *_current_thd(void)
 #include "sql_udf.h"
 #include "item.h"
 typedef Comp_creator* (*chooser_compare_func_creator)(bool invert);
+/* sql_parse.cc */
+void free_items(Item *item);
+void cleanup_items(Item *item);
+class THD;
+void close_thread_tables(THD *thd, bool locked=0, bool skip_derived=0);
 #include "sql_class.h"
 #include "opt_range.h"
 
@@ -411,7 +416,6 @@ bool mysql_rename_tables(THD *thd, TABLE_LIST *table_list);
 bool mysql_change_db(THD *thd,const char *name);
 void mysql_parse(THD *thd,char *inBuf,uint length);
 bool is_update_query(enum enum_sql_command command);
-void free_items(Item *item);
 bool alloc_query(THD *thd, char *packet, ulong packet_length);
 void mysql_init_select(LEX *lex);
 void mysql_init_query(THD *thd);
@@ -688,7 +692,6 @@ bool rm_temporary_table(enum db_type base, char *path);
 void free_io_cache(TABLE *entry);
 void intern_close_table(TABLE *entry);
 bool close_thread_table(THD *thd, TABLE **table_ptr);
-void close_thread_tables(THD *thd, bool locked=0, bool skip_derived=0);
 void close_temporary_tables(THD *thd);
 TABLE_LIST * find_table_in_list(TABLE_LIST *table,
 				const char *db_name, const char *table_name);
@@ -766,9 +769,6 @@ uint check_word(TYPELIB *lib, const char *val, const char *end,
 
 bool is_keyword(const char *name, uint len);
 
-/* sql_parse.cc */
-void free_items(Item *item);
-void cleanup_items(Item *item);
 
 #define MY_DB_OPT_FILE "db.opt"
 bool load_db_opt(THD *thd, const char *path, HA_CREATE_INFO *create);

sql/sql_base.cc

@@ -1631,6 +1631,14 @@ int open_and_lock_tables(THD *thd, TABLE_LIST *tables)
   if (open_tables(thd, tables, &counter) || lock_tables(thd, tables, counter))
     DBUG_RETURN(-1);				/* purecov: inspected */
   fix_tables_pointers(thd->lex->all_selects_list);
+
+  /*
+    open temporary memory pool, which will be closed in
+    mysql_test_select_fields,  mysql_test_upd_fields or
+    mysql_test_insert_fields
+  */
+  if (thd->current_statement)
+    thd->ps_setup_prepare_memory();
   DBUG_RETURN(mysql_handle_derived(thd->lex));
 }
 
@@ -2080,6 +2088,9 @@ int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
 {
   if (!wild_num)
     return 0;
+  Statement *stmt= thd->current_statement, backup;
+  if (stmt)
+    thd->set_n_backup_item_arena(stmt, &backup);
   reg2 Item *item;
   List_iterator<Item> it(fields);
   while ( wild_num && (item= it++))
@@ -2091,7 +2102,11 @@ int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
       uint elem= fields.elements;
       if (insert_fields(thd,tables,((Item_field*) item)->db_name,
 			((Item_field*) item)->table_name, &it))
+      {
+	if (stmt)
+	  thd->restore_backup_item_arena(stmt, &backup);
 	return (-1);
+      }
       if (sum_func_list)
       {
 	/*
@@ -2104,6 +2119,8 @@ int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
       wild_num--;
     }
   }
+  if (stmt)
+      thd->restore_backup_item_arena(stmt, &backup);
   return 0;
 }
 

sql/sql_class.cc

@@ -83,7 +83,7 @@ extern "C" void free_user_var(user_var_entry *entry)
 ** Thread specific functions
 ****************************************************************************/
 
-THD::THD():user_time(0), is_fatal_error(0),
+THD::THD():user_time(0), current_statement(0), is_fatal_error(0),
 	   last_insert_id_used(0),
 	   insert_id_used(0), rand_used(0), in_lock_tables(0),
 	   global_read_lock(0), bootstrap(0)
@@ -1247,6 +1247,27 @@ void Statement::set_statement(Statement *stmt)
 }
 
 
+void Statement::set_n_backup_item_arena(Statement *set, Statement *backup)
+{
+  backup->set_item_arena(this);
+  set_item_arena(set);
+}
+
+
+void Statement::restore_backup_item_arena(Statement *set, Statement *backup)
+{
+  set->set_item_arena(this);
+  set_item_arena(backup);
+  // reset backup mem_root to avoid its freeing
+  init_alloc_root(&backup->mem_root, 0, 0);
+}
+
+void Statement::set_item_arena(Statement *set)
+{
+  mem_root= set->mem_root;
+  free_list= set->free_list;
+}
+
 Statement::~Statement()
 {
   free_root(&mem_root, MYF(0));

sql/sql_class.h

@@ -427,7 +427,7 @@ class Statement
 public:
   /* FIXME: must be private */
   LEX     main_lex;
-public:
+
   /*
     Uniquely identifies each statement object in thread scope; change during
     statement lifetime. FIXME: must be const
@@ -503,6 +503,32 @@ class Statement
   void set_statement(Statement *stmt);
   /* return class type */
   virtual Type type() const;
+
+  inline gptr alloc(unsigned int size) { return alloc_root(&mem_root,size); }
+  inline gptr calloc(unsigned int size)
+  {
+    gptr ptr;
+    if ((ptr=alloc_root(&mem_root,size)))
+      bzero((char*) ptr,size);
+    return ptr;
+  }
+  inline char *strdup(const char *str)
+  { return strdup_root(&mem_root,str); }
+  inline char *strmake(const char *str, uint size)
+  { return strmake_root(&mem_root,str,size); }
+  inline char *memdup(const char *str, uint size)
+  { return memdup_root(&mem_root,str,size); }
+  inline char *memdup_w_gap(const char *str, uint size, uint gap)
+  {
+    gptr ptr;
+    if ((ptr=alloc_root(&mem_root,size+gap)))
+      memcpy(ptr,str,size);
+    return ptr;
+  }
+
+  void set_n_backup_item_arena(Statement *set, Statement *backup);
+  void restore_backup_item_arena(Statement *set, Statement *backup);
+  void Statement::set_item_arena(Statement *set);
 };
 
 
@@ -689,6 +715,10 @@ class THD :public ilink,
 #ifdef SIGNAL_WITH_VIO_CLOSE
   Vio* active_vio;
 #endif
+  /*
+    Current prepared Statement if there one, or 0
+  */
+  Statement *current_statement;
   /*
     next_insert_id is set on SET INSERT_ID= #. This is used as the next
     generated auto_increment value in handler.cc
@@ -850,34 +880,14 @@ class THD :public ilink,
     return 0;
 #endif
   }
-  inline gptr alloc(unsigned int size) { return alloc_root(&mem_root,size); }
-  inline gptr calloc(unsigned int size)
-  {
-    gptr ptr;
-    if ((ptr=alloc_root(&mem_root,size)))
-      bzero((char*) ptr,size);
-    return ptr;
-  }
-  inline char *strdup(const char *str)
-  { return strdup_root(&mem_root,str); }
-  inline char *strmake(const char *str, uint size)
-  { return strmake_root(&mem_root,str,size); }
-  inline char *memdup(const char *str, uint size)
-  { return memdup_root(&mem_root,str,size); }
-  inline char *memdup_w_gap(const char *str, uint size, uint gap)
+  inline gptr trans_alloc(unsigned int size) 
   { 
-    gptr ptr;
-    if ((ptr=alloc_root(&mem_root,size+gap)))
-      memcpy(ptr,str,size);
-    return ptr;
+    return alloc_root(&transaction.mem_root,size);
   }
+
   bool convert_string(LEX_STRING *to, CHARSET_INFO *to_cs,
 		      const char *from, uint from_length,
 		      CHARSET_INFO *from_cs);
-  inline gptr trans_alloc(unsigned int size) 
-  { 
-    return alloc_root(&transaction.mem_root,size);
-  }
   void add_changed_table(TABLE *table);
   void add_changed_table(const char *key, long key_length);
   CHANGED_TABLE_LIST * changed_table_dup(const char *key, long key_length);
@@ -900,6 +910,33 @@ class THD :public ilink,
   }
   inline CHARSET_INFO *charset() { return variables.character_set_client; }
   void update_charset();
+
+  inline void ps_setup_prepare_memory()
+  {
+    DBUG_ASSERT(current_statement!=0);
+    /*
+      We do not want to have in PS memory all that junk,
+      which will be created by preparation => substitute memory
+      from original thread pool.
+
+      We know that PS memory pool is now copied to THD, we move it back
+      to allow some code use it.
+    */
+    current_statement->set_item_arena(this);
+    init_sql_alloc(&mem_root,
+		   variables.query_alloc_block_size,
+		   variables.query_prealloc_size);
+    free_list= 0;
+  }
+  inline void ps_setup_free_memory()
+  {
+    DBUG_ASSERT(current_statement!=0);
+    cleanup_items(current_statement->free_list);
+    free_items(free_list);
+    close_thread_tables(this); // to close derived tables
+    free_root(&mem_root, MYF(0));
+    set_item_arena(current_statement);
+  }
 };
 
 /* Flags for the THD::system_thread (bitmap) variable */

sql/sql_lex.cc

@@ -1500,8 +1500,14 @@ bool st_select_lex::setup_ref_array(THD *thd, uint order_group_num)
 {
   if (ref_pointer_array)
     return 0;
+
+  /*
+    We have to create array in prepared statement memory if it is
+    prepared statement
+  */
+  Statement *stmt= thd->current_statement ? thd->current_statement : thd;
   return (ref_pointer_array= 
-	  (Item **)thd->alloc(sizeof(Item*) *
+	  (Item **)stmt->alloc(sizeof(Item*) *
 			       (item_list.elements +
 				select_n_having_items +
 				order_group_num)* 5)) == 0;
@@ -1629,7 +1635,11 @@ void st_select_lex::print_limit(THD *thd, String *str)
 
 /*
   There are st_select_lex::add_table_to_list & 
-  st_select_lex::set_lock_for_tables in sql_parse.cc
+  st_select_lex::set_lock_for_tables are in sql_parse.cc
 
   st_select_lex::print is in sql_select.h
+
+  st_select_lex_unit::prepare, st_select_lex_unit::exec,
+  st_select_lex_unit::cleanup, st_select_lex_unit::reinit_exec_mechanism
+  are in sql_union.cc
 */

sql/sql_lex.h

@@ -355,6 +355,8 @@ class st_select_lex_unit: public st_select_lex_node {
   int prepare(THD *thd, select_result *result, ulong additional_options);
   int exec();
   int cleanup();
+  inline void unclean() { cleaned= 0; }
+  void reinit_exec_mechanism();
 
   bool check_updateable(char *db, char *table);
   void print(String *str);

sql/sql_prepare.cc

@@ -622,7 +622,12 @@ static bool mysql_test_insert_fields(Prepared_statement *stmt,
     DBUG_RETURN(1); 
 #endif
   if (open_and_lock_tables(thd, table_list))
+  {
+    // this memory pool was opened in open_and_lock_tables
+    thd->ps_setup_free_memory();
     DBUG_RETURN(1);
+  }
+
   table= table_list->table;
 
   if ((values= its++))
@@ -631,7 +636,12 @@ static bool mysql_test_insert_fields(Prepared_statement *stmt,
     ulong counter= 0;
     
     if (check_insert_fields(thd,table,fields,*values,1))
+    {
+      thd->ps_setup_free_memory();
       DBUG_RETURN(1);
+    }
+    // this memory pool was opened in open_and_lock_tables
+    thd->ps_setup_free_memory();
 
     value_count= values->elements;
     its.rewind();
@@ -648,6 +658,11 @@ static bool mysql_test_insert_fields(Prepared_statement *stmt,
       }
     }
   }
+  else
+  {
+    // this memory pool was opened in open_and_lock_tables
+    thd->ps_setup_free_memory();
+  }
   if (send_prep_stmt(stmt, 0))
     DBUG_RETURN(1);
   DBUG_RETURN(0);
@@ -678,11 +693,20 @@ static bool mysql_test_upd_fields(Prepared_statement *stmt,
     DBUG_RETURN(1);
 #endif
   if (open_and_lock_tables(thd, table_list))
+  {
+    // this memory pool was opened in open_and_lock_tables
+    thd->ps_setup_free_memory();
     DBUG_RETURN(1);
   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)
+  {
+    // this memory pool was opened in open_and_lock_tables
+    thd->ps_setup_free_memory();
     DBUG_RETURN(1);
+  }
+  // this memory pool was opened in open_and_lock_tables
+  thd->ps_setup_free_memory();
 
   /* 
      Currently return only column list info only, and we are not
@@ -737,39 +761,50 @@ static bool mysql_test_select_fields(Prepared_statement *stmt,
    DBUG_RETURN(1);
     
   if (open_and_lock_tables(thd, tables))
+  {
+    // this memory pool was opened in open_and_lock_tables
+    thd->ps_setup_free_memory();
     DBUG_RETURN(1);
+  }
 
   if (lex->describe)
   {
     if (send_prep_stmt(stmt, 0))
-      DBUG_RETURN(1);      
+      goto err;
   }
   else 
   {
     if (!result && !(result= new select_send()))
     {
       send_error(thd, ER_OUT_OF_RESOURCES);
-      DBUG_RETURN(1);
+      goto err;
     }
 
-    JOIN *join= new JOIN(thd, fields, select_options, result);
     thd->used_tables= 0;	// Updated by setup_fields  
 
-    if (join->prepare(&select_lex->ref_pointer_array,
-		      (TABLE_LIST*)select_lex->get_table_list(),
-                      wild_num, conds, og_num, order, group, having, proc, 
-                      select_lex, unit))
-      DBUG_RETURN(1);
+    if (unit->prepare(thd, result, 0))
+      goto err_prep;
+
     if (send_prep_stmt(stmt, fields.elements) ||
         thd->protocol_simple.send_fields(&fields, 0)
 #ifndef EMBEDDED_LIBRARY
 	|| net_flush(&thd->net)
 #endif
 	)
-      DBUG_RETURN(1);
-    join->cleanup();
+      goto err_prep;
+
+    unit->cleanup();
   }
+  // this memory pool was opened in open_and_lock_tables
+  thd->ps_setup_free_memory();
   DBUG_RETURN(0);
+
+err_prep:
+  unit->cleanup();
+err:
+  // this memory pool was opened in open_and_lock_tables
+  thd->ps_setup_free_memory();
+  DBUG_RETURN(1);
 }
 
 
@@ -898,6 +933,7 @@ bool mysql_stmt_prepare(THD *thd, char *packet, uint packet_length)
 
   thd->stmt_backup.set_statement(thd);
   thd->set_statement(stmt);
+  thd->current_statement= stmt;
 
   if (alloc_query(thd, packet, packet_length))
     goto alloc_query_err;
@@ -925,9 +961,9 @@ bool mysql_stmt_prepare(THD *thd, char *packet, uint packet_length)
     sl->prep_where= sl->where;
   }
 
-  cleanup_items(thd->free_list);
   stmt->set_statement(thd);
   thd->set_statement(&thd->stmt_backup);
+  thd->current_statement= 0;
 
   if (init_param_items(stmt))
     goto init_param_err;
@@ -944,8 +980,10 @@ bool mysql_stmt_prepare(THD *thd, char *packet, uint packet_length)
 alloc_query_err:
   /* Statement map deletes statement on erase */
   thd->stmt_map.erase(stmt);
+  thd->current_statement= 0;
   DBUG_RETURN(1);
 insert_stmt_err:
+  thd->current_statement= 0;
   delete stmt;
   DBUG_RETURN(1);
 }
@@ -1010,24 +1048,36 @@ void mysql_stmt_execute(THD *thd, char *packet)
     /* Fix ORDER list */
     for (order=(ORDER *)sl->order_list.first ; order ; order=order->next)
       order->item= (Item **)(order+1);
-  }
 
     /*
       TODO: When the new table structure is ready, then have a status bit 
       to indicate the table is altered, and re-do the setup_* 
       and open the tables back.
     */
-  for (TABLE_LIST *tables= (TABLE_LIST*) stmt->lex->select_lex.table_list.first;
+    for (TABLE_LIST *tables= (TABLE_LIST*) sl->table_list.first;
 	 tables;
 	 tables= tables->next)
+    {
       tables->table= 0; // safety - nasty init
+      tables->table_list= 0;
+    }
+    
+    {
+      SELECT_LEX_UNIT *unit= sl->master_unit();
+      unit->unclean();
+      unit->types.empty();
+      // for derived tables & PS (which can't be reset bu Item_subquery)
+      unit->reinit_exec_mechanism();
+    }
+  }
+
 
 #ifndef EMBEDDED_LIBRARY
   if (stmt->param_count && setup_params_data(stmt))
-    DBUG_VOID_RETURN;
+    goto end;
 #else
   if (stmt->param_count && (*stmt->setup_params_data)(stmt))
-    DBUG_VOID_RETURN;
+    goto end;
 #endif
 
   if (!(specialflag & SPECIAL_NO_PRIOR))
@@ -1048,8 +1098,10 @@ void mysql_stmt_execute(THD *thd, char *packet)
 
   free_items(thd->free_list);
   cleanup_items(stmt->free_list);
+  close_thread_tables(thd); // to close derived tables
   free_root(&thd->mem_root, MYF(0));
   thd->set_statement(&thd->stmt_backup);
+end:
   DBUG_VOID_RETURN;
 }
 

sql/sql_select.cc

@@ -327,8 +327,7 @@ JOIN::prepare(Item ***rref_pointer_array,
   // Is it subselect
   {
     Item_subselect *subselect;
-    if ((subselect= select_lex->master_unit()->item) &&
-	select_lex->linkage != GLOBAL_OPTIONS_TYPE)
+    if ((subselect= select_lex->master_unit()->item))
     {
       Item_subselect::trans_res res;
       if ((res= subselect->select_transformer(this)) !=

sql/sql_union.cc

@@ -453,3 +453,9 @@ int st_select_lex_unit::cleanup()
   }
   DBUG_RETURN(error);
 }
+
+
+void st_select_lex_unit::reinit_exec_mechanism()
+{
+  prepared= optimized= executed= 0;
+}

tests/client_test.c

@@ -8189,6 +8189,90 @@ static void test_bug2247()
   fprintf(stdout, "OK");
 }
 
+
+
+static void test_subqueries()
+{
+  MYSQL_STMT *stmt;
+  int rc, i;
+  const char *query= "SELECT (SELECT SUM(a+b) FROM t2 where t1.b=t2.b GROUP BY t1.a LIMIT 1) as scalar_s, exists (select 1 from t2 where t2.a/2=t1.a) as exists_s, a in (select a+3 from t2) as in_s, (a-1,b-1) in (select a,b from t2) as in_row_s FROM t1, (select a x, b y from t2) tt WHERE x=a";
+
+  myheader("test_subquery");
+  
+  rc = mysql_query(mysql, "DROP TABLE IF EXISTS t1,t2");
+  myquery(rc);
+  
+  rc= mysql_query(mysql,"CREATE TABLE t1 (a int , b int);");
+  myquery(rc);
+
+  rc= mysql_query(mysql,
+		  "insert into t1 values (1,1), (2, 2), (3,3), (4,4), (5,5);");
+  myquery(rc);
+
+  rc= mysql_query(mysql,"create table t2 select * from t1;");
+  myquery(rc);
+
+  stmt= mysql_prepare(mysql, query, strlen(query));
+  mystmt_init(stmt);
+  for (i= 0; i < 3; i++)
+  {
+    rc= mysql_execute(stmt);
+    mystmt(stmt, rc);
+    assert(5 == my_process_stmt_result(stmt));
+  }
+  mysql_stmt_close(stmt);
+
+  rc= mysql_query(mysql, "DROP TABLE t1,t2");
+  myquery(rc);
+}
+
+
+static void test_bad_union()
+{
+  MYSQL_STMT *stmt;
+  const char *query= "SELECT 1, 2 union SELECT 1";
+
+  myheader("test_bad_union");
+  
+  stmt= mysql_prepare(mysql, query, strlen(query));
+  assert(stmt == 0);
+  myerror(NULL); 
+}
+
+static void test_distinct()
+{
+  MYSQL_STMT *stmt;
+  int rc, i;
+  const char *query= 
+    "SELECT 2+count(distinct b), group_concat(a) FROM t1 group by a";
+
+  myheader("test_subquery");
+  
+  rc = mysql_query(mysql, "DROP TABLE IF EXISTS t1");
+  myquery(rc);
+  
+  rc= mysql_query(mysql,"CREATE TABLE t1 (a int , b int);");
+  myquery(rc);
+
+  rc= mysql_query(mysql,
+		  "insert into t1 values (1,1), (2, 2), (3,3), (4,4), (5,5),\
+(1,10), (2, 20), (3,30), (4,40), (5,50)\;");
+  myquery(rc);
+
+  for (i= 0; i < 3; i++)
+  {
+    stmt= mysql_prepare(mysql, query, strlen(query));
+    mystmt_init(stmt);
+    rc= mysql_execute(stmt);
+    mystmt(stmt, rc);
+    assert(5 == my_process_stmt_result(stmt));
+    mysql_stmt_close(stmt);
+  }
+
+  rc= mysql_query(mysql, "DROP TABLE t1");
+  myquery(rc);
+}
+
 /*
   Test for bug#2248 "mysql_fetch without prior mysql_execute hangs"
 */
@@ -8385,6 +8469,9 @@ int main(int argc, char **argv)
     test_count= 1;
    
     start_time= time((time_t *)0);
+
+    test_subqueries();
+
     client_query();         /* simple client query test */
 #if NOT_YET_WORKING
     /* Used for internal new development debugging */
@@ -8437,7 +8524,8 @@ int main(int argc, char **argv)
     client_use_result();    /* usage of mysql_use_result() */  
     test_tran_bdb();        /* transaction test on BDB table type */
     test_tran_innodb();     /* transaction test on InnoDB table type */ 
-    test_prepare_ext();     /* test prepare with all types conversion -- TODO */
+    test_prepare_ext();     /* test prepare with all types
+			       conversion -- TODO */
     test_prepare_syntax();  /* syntax check for prepares */
     test_field_names();     /* test for field names */
     test_field_flags();     /* test to help .NET provider team */
@@ -8450,7 +8538,7 @@ int main(int argc, char **argv)
     test_stmt_close();      /* mysql_stmt_close() test -- hangs */
     test_prepare_field_result(); /* prepare meta info */
     test_multi_stmt();      /* multi stmt test */
-    test_multi_statements(); /* test multi statement execution */
+/*    test_multi_statements(); *//* test multi statement execution */
     test_store_result();    /* test the store_result */
     test_store_result1();   /* test store result without buffers */
     test_store_result2();   /* test store result for misc case */
@@ -8497,6 +8585,10 @@ int main(int argc, char **argv)
     test_bug2247();         /* test that mysql_stmt_affected_rows() returns
                                number of rows affected by last prepared 
                                statement execution */
+    test_subqueries();	    /* repeatable subqueries */
+    test_bad_union();       /* correct setup of UNION */
+    test_distinct();	    /* distinct aggregate functions */
+
 
     end_time= time((time_t *)0);
     total_time+= difftime(end_time, start_time);