diff options
Diffstat (limited to 'sql')
| -rw-r--r-- | sql/sql_select.cc | 73 | ||||
| -rw-r--r-- | sql/sql_select.h | 9 |
2 files changed, 40 insertions, 42 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 90a5c5c4c8b..75c11c2ac64 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -87,7 +87,6 @@ static store_key *get_store_key(THD *thd, KEYUSE *keyuse, table_map used_tables, KEY_PART_INFO *key_part, uchar *key_buff, uint maybe_null); -static bool make_simple_join(JOIN *join,TABLE *tmp_table); static void make_outerjoin_info(JOIN *join); static bool make_join_select(JOIN *join,SQL_SELECT *select,COND *item); static void make_join_readinfo(JOIN *join, ulonglong options); @@ -1879,7 +1878,7 @@ JOIN::exec() /* Free first data from old join */ curr_join->join_free(); - if (make_simple_join(curr_join, curr_tmp_table)) + if (curr_join->make_simple_join(this, curr_tmp_table)) DBUG_VOID_RETURN; calc_group_buffer(curr_join, group_list); count_field_types(select_lex, &curr_join->tmp_table_param, @@ -2002,7 +2001,7 @@ JOIN::exec() curr_join->select_distinct=0; } curr_tmp_table->reginfo.lock_type= TL_UNLOCK; - if (make_simple_join(curr_join, curr_tmp_table)) + if (curr_join->make_simple_join(this, curr_tmp_table)) DBUG_VOID_RETURN; calc_group_buffer(curr_join, curr_join->group_list); count_field_types(select_lex, &curr_join->tmp_table_param, @@ -5686,48 +5685,42 @@ store_val_in_field(Field *field, Item *item, enum_check_fields check_flag) } -static bool -make_simple_join(JOIN *join,TABLE *tmp_table) +/** + @details Initialize a JOIN as a query execution plan + that accesses a single table via a table scan. + + @param parent contains JOIN_TAB and TABLE object buffers for this join + @param tmp_table temporary table + + @retval FALSE success + @retval TRUE error occurred +*/ +bool +JOIN::make_simple_join(JOIN *parent, TABLE *tmp_table) { - TABLE **tableptr; - JOIN_TAB *join_tab; - DBUG_ENTER("make_simple_join"); + DBUG_ENTER("JOIN::make_simple_join"); /* Reuse TABLE * and JOIN_TAB if already allocated by a previous call to this function through JOIN::exec (may happen for sub-queries). */ - if (!join->table_reexec) - { - if (!(join->table_reexec= (TABLE**) join->thd->alloc(sizeof(TABLE*)))) - DBUG_RETURN(TRUE); /* purecov: inspected */ - if (join->tmp_join) - join->tmp_join->table_reexec= join->table_reexec; - } - if (!join->join_tab_reexec) - { - if (!(join->join_tab_reexec= - (JOIN_TAB*) join->thd->alloc(sizeof(JOIN_TAB)))) - DBUG_RETURN(TRUE); /* purecov: inspected */ - if (join->tmp_join) - join->tmp_join->join_tab_reexec= join->join_tab_reexec; - } - tableptr= join->table_reexec; - join_tab= join->join_tab_reexec; - - join->join_tab=join_tab; - join->table=tableptr; tableptr[0]=tmp_table; - join->tables=1; - join->const_tables=0; - join->const_table_map=0; - 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; - join->first_record=join->sort_and_group=0; - join->send_records=(ha_rows) 0; - join->group=0; - join->row_limit=join->unit->select_limit_cnt; - join->do_send_rows = (join->row_limit) ? 1 : 0; + if (!parent->join_tab_reexec && + !(parent->join_tab_reexec= (JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB)))) + DBUG_RETURN(TRUE); /* purecov: inspected */ + + join_tab= parent->join_tab_reexec; + table= &parent->table_reexec[0]; parent->table_reexec[0]= tmp_table; + tables= 1; + const_tables= 0; + const_table_map= 0; + tmp_table_param.field_count= tmp_table_param.sum_func_count= + tmp_table_param.func_count= 0; + tmp_table_param.copy_field= tmp_table_param.copy_field_end=0; + first_record= sort_and_group=0; + send_records= (ha_rows) 0; + group= 0; + row_limit= unit->select_limit_cnt; + do_send_rows= row_limit ? 1 : 0; join_tab->cache.buff=0; /* No caching */ join_tab->table=tmp_table; @@ -5744,7 +5737,7 @@ make_simple_join(JOIN *join,TABLE *tmp_table) join_tab->ref.key = -1; join_tab->not_used_in_distinct=0; join_tab->read_first_record= join_init_read_record; - join_tab->join=join; + join_tab->join= this; join_tab->ref.key_parts= 0; bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record)); tmp_table->status=0; diff --git a/sql/sql_select.h b/sql/sql_select.h index c5961f097c2..7d794b71f4d 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -402,9 +402,12 @@ public: cleared only at the end of the execution of the whole query and not caching allocations that occur in repetition at execution time will result in excessive memory usage. + Note: make_simple_join always creates an execution plan that accesses + a single table, thus it is sufficient to have a one-element array for + table_reexec. */ SORT_FIELD *sortorder; // make_unireg_sortorder() - TABLE **table_reexec; // make_simple_join() + TABLE *table_reexec[1]; // make_simple_join() JOIN_TAB *join_tab_reexec; // make_simple_join() /* end of allocation caching storage */ @@ -434,7 +437,7 @@ public: exec_tmp_table1= 0; exec_tmp_table2= 0; sortorder= 0; - table_reexec= 0; + table_reexec[0]= 0; join_tab_reexec= 0; thd= thd_arg; sum_funcs= sum_funcs2= 0; @@ -526,6 +529,8 @@ public: return (unit == &thd->lex->unit && (unit->fake_select_lex == 0 || select_lex == unit->fake_select_lex)); } +private: + bool make_simple_join(JOIN *join, TABLE *tmp_table); }; |