From b42ec166c043a95206bb27f84538893b50c1b829 Mon Sep 17 00:00:00 2001 From: "Sinisa@sinisa.nasamreza.org" <> Date: Thu, 28 Feb 2002 13:50:00 +0200 Subject: [PATCH] Surgical changes in sql_select and sql_union code in order to accomodate EXPLAIN properly for all possible variant of UNION's derived tables etc ... This also fixes all reported (and unreported) bugs when EXPLAIN is run on UNION's. select_describe() now has a very dirty hack to avoid some problems with transactional tables on table unlocking. Code speedup is possible. For the moment all that was important was that all tests are passed. --- sql/sql_select.cc | 108 ++++++++++++++++++++++++---------------------- sql/sql_union.cc | 58 ++++++++++++------------- 2 files changed, 85 insertions(+), 81 deletions(-) diff --git a/sql/sql_select.cc b/sql/sql_select.cc index ae6c38a874e..3135fe050dc 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -6963,13 +6963,16 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, { List field_list; Item *item; + List item_list; THD *thd=join->thd; + MYSQL_LOCK *save_lock; SELECT_LEX *select_lex = &(join->thd->lex.select_lex); + select_result *result=join->result; DBUG_ENTER("select_describe"); /* Don't log this into the slow query log */ select_lex->options&= ~(QUERY_NO_INDEX_USED | QUERY_NO_GOOD_INDEX_USED); - if (join->thd->lex.select == select_lex) + if (thd->lex.select == select_lex) { field_list.push_back(new Item_empty_string("table",NAME_LEN)); field_list.push_back(new Item_empty_string("type",10)); @@ -6985,24 +6988,22 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, item->maybe_null=1; field_list.push_back(new Item_real("rows",0.0,0,10)); field_list.push_back(new Item_empty_string("Extra",255)); - if (send_fields(thd,field_list,1)) + if (result->send_fields(field_list,1)) return; } - char buff[512],*buff_ptr; - String tmp(buff,sizeof(buff)),*packet= &thd->packet; + if (message) { - packet->length(0); - net_store_null(packet); - net_store_null(packet); - net_store_null(packet); - net_store_null(packet); - net_store_null(packet); - net_store_null(packet); - net_store_null(packet); - net_store_data(packet,message,strlen(message)); - if (my_net_write(&thd->net,(char*) packet->ptr(),packet->length())) - DBUG_VOID_RETURN; + item_list.push_back(new Item_empty_string("",0)); + item_list.push_back(new Item_empty_string("",0)); + item_list.push_back(new Item_empty_string("",0)); + item_list.push_back(new Item_empty_string("",0)); + item_list.push_back(new Item_empty_string("",0)); + item_list.push_back(new Item_empty_string("",0)); + item_list.push_back(new Item_empty_string("",0)); + item_list.push_back(new Item_string(message,strlen(message))); + if (result->send_data(item_list)) + result->send_error(0,NullS); } else { @@ -7011,69 +7012,70 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, { JOIN_TAB *tab=join->join_tab+i; TABLE *table=tab->table; - + char buff[512],*buff_ptr=buff; + char buff1[512], buff2[512], bufff[512]; + String tmp1(buff1,sizeof(buff1)); + String tmp2(buff2,sizeof(buff2)); + item_list.empty(); if (tab->type == JT_ALL && tab->select && tab->select->quick) tab->type= JT_RANGE; - packet->length(0); - net_store_data(packet,table->table_name); - net_store_data(packet,join_type_str[tab->type]); - tmp.length(0); + item_list.push_back(new Item_string(table->table_name,strlen(table->table_name))); + item_list.push_back(new Item_string(join_type_str[tab->type],strlen(join_type_str[tab->type]))); + tmp1.length(0); tmp2.length(0); key_map bits; uint j; for (j=0,bits=tab->keys ; bits ; j++,bits>>=1) { if (bits & 1) { - if (tmp.length()) - tmp.append(','); - tmp.append(table->key_info[j].name); + if (tmp1.length()) + tmp1.append(','); + tmp1.append(table->key_info[j].name); } } - if (tmp.length()) - net_store_data(packet,tmp.ptr(),tmp.length()); + if (tmp1.length()) + item_list.push_back(new Item_string(tmp1.ptr(),tmp1.length())); else - net_store_null(packet); + item_list.push_back(new Item_null()); if (tab->ref.key_parts) { - net_store_data(packet,table->key_info[tab->ref.key].name); - net_store_data(packet,(uint32) tab->ref.key_length); - tmp.length(0); + item_list.push_back(new Item_string(table->key_info[tab->ref.key].name,strlen(table->key_info[tab->ref.key].name))); + item_list.push_back(new Item_int((int) tab->ref.key_length)); for (store_key **ref=tab->ref.key_copy ; *ref ; ref++) { - if (tmp.length()) - tmp.append(','); - tmp.append((*ref)->name()); + if (tmp2.length()) + tmp2.append(','); + tmp2.append((*ref)->name()); } - net_store_data(packet,tmp.ptr(),tmp.length()); + item_list.push_back(new Item_string(tmp2.ptr(),tmp2.length())); } else if (tab->type == JT_NEXT) { - net_store_data(packet,table->key_info[tab->index].name); - net_store_data(packet,(uint32) table->key_info[tab->index].key_length); - net_store_null(packet); + item_list.push_back(new Item_string(table->key_info[tab->index].name,strlen(table->key_info[tab->index].name))); + item_list.push_back(new Item_int((int) table->key_info[tab->index].key_length)); + item_list.push_back(new Item_null()); } else if (tab->select && tab->select->quick) { - net_store_data(packet,table->key_info[tab->select->quick->index].name);; - net_store_data(packet,(uint32) tab->select->quick->max_used_key_length); - net_store_null(packet); + item_list.push_back(new Item_string(table->key_info[tab->select->quick->index].name,strlen(table->key_info[tab->select->quick->index].name))); + item_list.push_back(new Item_int((int) tab->select->quick->max_used_key_length)); + item_list.push_back(new Item_null()); } else { - net_store_null(packet); - net_store_null(packet); - net_store_null(packet); + item_list.push_back(new Item_null()); + item_list.push_back(new Item_null()); + item_list.push_back(new Item_null()); } - sprintf(buff,"%.0f",join->best_positions[i].records_read); - net_store_data(packet,buff); + sprintf(bufff,"%.0f",join->best_positions[i].records_read); + item_list.push_back(new Item_string(bufff,strlen(bufff))); my_bool key_read=table->key_read; if (tab->type == JT_NEXT && ((table->used_keys & ((key_map) 1 << tab->index)))) key_read=1; - buff_ptr=buff; if (tab->info) - net_store_data(packet,tab->info); + item_list.push_back(new Item_string(tab->info,strlen(tab->info))); else if (tab->select) { if (tab->use_quick == 2) @@ -7127,16 +7129,20 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, } buff_ptr=strmov(buff_ptr,"Distinct"); } - net_store_data(packet,buff,(uint) (buff_ptr - buff)); - if (my_net_write(&thd->net,(char*) packet->ptr(),packet->length())) - DBUG_VOID_RETURN; /* Purecov: Inspected */ - + item_list.push_back(new Item_string(buff,(uint) (buff_ptr - buff))); // For next iteration used_tables|=table->map; + if (result->send_data(item_list)) + result->send_error(0,NullS); } } if (!join->thd->lex.select->next) - send_eof(&thd->net); + { + save_lock=thd->lock; + thd->lock=(MYSQL_LOCK *)0; + result->send_eof(); + thd->lock=save_lock; + } DBUG_VOID_RETURN; } diff --git a/sql/sql_union.cc b/sql/sql_union.cc index 51ad2425022..60155e0ce8d 100644 --- a/sql/sql_union.cc +++ b/sql/sql_union.cc @@ -31,10 +31,11 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) ORDER *order; List item_list; TABLE *table; + int describe=(lex->select_lex.options & SELECT_DESCRIBE) ? 1 : 0; + int res; TABLE_LIST result_table_list; TMP_TABLE_PARAM tmp_table_param; select_union *union_result; - int res; DBUG_ENTER("mysql_union"); /* Fix tables 'to-be-unioned-from' list to point at opened tables */ @@ -70,33 +71,26 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) lex_sl=0; order=0; } - - if (lex->select_lex.options & SELECT_DESCRIBE) + + if (describe) { - for (sl= &lex->select_lex; sl; sl=sl->next) - { - lex->select=sl; - thd->offset_limit=sl->offset_limit; - thd->select_limit=sl->select_limit+sl->offset_limit; - if (thd->select_limit < sl->select_limit) - thd->select_limit= HA_POS_ERROR; // no limit - if (thd->select_limit == HA_POS_ERROR) - sl->options&= ~OPTION_FOUND_ROWS; - res=mysql_select(thd, (TABLE_LIST*) sl->table_list.first, - sl->item_list, - sl->where, - ((sl->braces) ? - (ORDER *) sl->order_list.first : (ORDER *) 0), - (ORDER*) sl->group_list.first, - sl->having, - (ORDER*) NULL, - (sl->options | thd->options | SELECT_NO_UNLOCK | - SELECT_DESCRIBE), - result); - } - DBUG_RETURN(0); + Item *item; + item_list.push_back(new Item_empty_string("table",NAME_LEN)); + item_list.push_back(new Item_empty_string("type",10)); + item_list.push_back(item=new Item_empty_string("possible_keys", + NAME_LEN*MAX_KEY)); + item->maybe_null=1; + item_list.push_back(item=new Item_empty_string("key",NAME_LEN)); + item->maybe_null=1; + item_list.push_back(item=new Item_int("key_len",0,3)); + item->maybe_null=1; + item_list.push_back(item=new Item_empty_string("ref", + NAME_LEN*MAX_REF_PARTS)); + item->maybe_null=1; + item_list.push_back(new Item_real("rows",0.0,0,10)); + item_list.push_back(new Item_empty_string("Extra",255)); } - + else { Item *item; List_iterator it(lex->select_lex.item_list); @@ -113,7 +107,7 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) bzero((char*) &tmp_table_param,sizeof(tmp_table_param)); tmp_table_param.field_count=item_list.elements; if (!(table=create_tmp_table(thd, &tmp_table_param, item_list, - (ORDER*) 0, !lex->union_option, + (ORDER*) 0, !describe & !lex->union_option, 1, 0, (lex->select_lex.options | thd->options | TMP_TABLE_ALL_COLUMNS)))) @@ -130,7 +124,9 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) res= -1; goto exit; } - for (sl= &lex->select_lex; sl; sl=sl->next) + union_result->save_time_stamp=!describe; + + for (sl=&lex->select_lex;sl;sl=sl->next) { thd->offset_limit=sl->offset_limit; thd->select_limit=sl->select_limit+sl->offset_limit; @@ -146,7 +142,7 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) (ORDER*) sl->group_list.first, sl->having, (ORDER*) NULL, - sl->options | thd->options | SELECT_NO_UNLOCK, + sl->options | thd->options | SELECT_NO_UNLOCK | ((describe) ? SELECT_DESCRIBE : 0), union_result); if (res) goto exit; @@ -187,6 +183,8 @@ int mysql_union(THD *thd, LEX *lex,select_result *result) if (thd->select_limit == HA_POS_ERROR) thd->options&= ~OPTION_FOUND_ROWS; } + if (describe) + thd->select_limit= HA_POS_ERROR; // no limit res=mysql_select(thd,&result_table_list, item_list, NULL, /*ftfunc_list,*/ order, (ORDER*) NULL, NULL, (ORDER*) NULL, @@ -222,7 +220,7 @@ select_union::~select_union() int select_union::prepare(List &list) { - if (list.elements != table->fields) + if (save_time_stamp && list.elements != table->fields) { my_message(ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT, ER(ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT),MYF(0));