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Some code optimisations related to EXPLAIN of derived tables and the

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resulting code cleanup in our main loop.
This commit is contained in:
Sinisa@sinisa.nasamreza.org
2002-11-09 15:40:46 +02:00
parent bd6f8e0b5f
commit d96c670c70
6 changed files with 37 additions and 90 deletions
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107
sql/sql_parse.cc
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@@ -1328,74 +1328,24 @@ mysql_execute_command(THD *thd)
#endif
}
select_result *explain_result= 0;
/*
TODO: make derived tables processing 'inside' SELECT processing.
TODO: solve problem with depended derived tables in subselects
*/
if (lex->sql_command == SQLCOM_SELECT &&
lex->describe && lex->derived_tables)
{
if (!(explain_result= new select_send()))
{
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_VOID_RETURN;
}
//check rights
for (cursor= tables;
cursor;
cursor= cursor->next)
if (cursor->derived)
{
TABLE_LIST *tables=
(TABLE_LIST *)((SELECT_LEX_UNIT *)
cursor->derived)->first_select()->table_list.first;
int res;
if (tables)
res= check_table_access(thd,SELECT_ACL, tables);
else
res= check_access(thd, SELECT_ACL, any_db);
if (res)
DBUG_VOID_RETURN;
}
thd->send_explain_fields(explain_result);
// EXPLAIN derived tables
for (cursor= tables;
cursor;
cursor= cursor->next)
if (cursor->derived)
{
SELECT_LEX *select_lex= ((SELECT_LEX_UNIT *)
cursor->derived)->first_select();
if (!open_and_lock_tables(thd,
(TABLE_LIST*) select_lex->table_list.first))
{
mysql_explain_select(thd, select_lex,
"DERIVED", explain_result);
// execute derived table SELECT to provide table for other SELECTs
if (mysql_derived(thd, lex, (SELECT_LEX_UNIT *)cursor->derived,
cursor, 1))
DBUG_VOID_RETURN;
}
else
DBUG_VOID_RETURN;
}
}
else if (lex->derived_tables)
if (lex->derived_tables)
{
for (TABLE_LIST *cursor= tables;
cursor;
cursor= cursor->next)
if (cursor->derived && (res=mysql_derived(thd, lex,
(SELECT_LEX_UNIT *)cursor->derived,
cursor, 0)))
cursor)))
{
if (res < 0)
send_error(thd,thd->killed ? ER_SERVER_SHUTDOWN : 0);
DBUG_VOID_RETURN;
}
}
}
if ((lex->select_lex.next_select_in_list() &&
lex->unit.create_total_list(thd, lex, &tables)) ||
(table_rules_on && tables && thd->slave_thread &&
@@ -1435,19 +1385,18 @@ mysql_execute_command(THD *thd)
{
if (lex->describe)
{
if (!explain_result)
if (!(explain_result= new select_send()))
{
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_VOID_RETURN;
}
else
thd->send_explain_fields(explain_result);
if (!(result= new select_send()))
{
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_VOID_RETURN;
}
else
thd->send_explain_fields(result);
fix_tables_pointers(select_lex);
res= mysql_explain_union(thd, &thd->lex.unit, explain_result);
res= mysql_explain_union(thd, &thd->lex.unit, result);
MYSQL_LOCK *save_lock= thd->lock;
thd->lock= (MYSQL_LOCK *)0;
explain_result->send_eof();
result->send_eof();
thd->lock= save_lock;
}
else
@@ -2901,26 +2850,24 @@ void
mysql_init_query(THD *thd)
{
DBUG_ENTER("mysql_init_query");
thd->lex.unit.init_query();
thd->lex.unit.init_select();
thd->lex.select_lex.init_query();
thd->lex.unit.slave= &thd->lex.select_lex;
thd->lex.unit.global_parameters= &thd->lex.select_lex; //Global limit & order
thd->lex.select_lex.master= &thd->lex.unit;
thd->lex.select_lex.prev= &thd->lex.unit.slave;
thd->select_number= thd->lex.select_lex.select_number= 1;
thd->lex.value_list.empty();
LEX *lex=&thd->lex;
lex->unit.init_query();
lex->unit.init_select();
lex->select_lex.init_query();
lex->value_list.empty();
lex->param_list.empty();
lex->unit.global_parameters= lex->unit.slave= lex->current_select= &lex->select_lex;
lex->select_lex.master= &lex->unit;
lex->select_lex.prev= &lex->unit.slave;
lex->olap=lex->describe=0;
lex->derived_tables= false;
thd->select_number= lex->select_lex.select_number= 1;
thd->free_list= 0;
thd->lex.current_select= &thd->lex.select_lex;
thd->lex.olap=thd->lex.describe=0;
thd->lex.select_lex.olap= UNSPECIFIED_OLAP_TYPE;
thd->fatal_error= 0; // Safety
thd->total_warn_count=0; // Warnings for this query
thd->last_insert_id_used= thd->query_start_used= thd->insert_id_used=0;
thd->sent_row_count= thd->examined_row_count= 0;
thd->rand_used=0;
thd->fatal_error= thd->rand_used=0;
thd->safe_to_cache_query= 1;
thd->lex.param_list.empty();
DBUG_VOID_RETURN;
}
@@ -2932,7 +2879,6 @@ mysql_init_select(LEX *lex)
select_lex->init_select();
select_lex->master_unit()->select_limit= select_lex->select_limit=
lex->thd->variables.select_limit;
select_lex->olap= UNSPECIFIED_OLAP_TYPE;
lex->exchange= 0;
lex->result= 0;
lex->proc_list.first= 0;
@@ -3016,14 +2962,13 @@ mysql_parse(THD *thd, char *inBuf, uint length)
mysql_init_query(thd);
thd->query_length = length;
thd->lex.derived_tables= false;
if (query_cache_send_result_to_client(thd, inBuf, length) <= 0)
{
LEX *lex=lex_start(thd, (uchar*) inBuf, length);
if (!yyparse() && ! thd->fatal_error)
{
if (mqh_used && thd->user_connect &&
check_mqh(thd, thd->lex.sql_command))
check_mqh(thd, lex->sql_command))
{
thd->net.error = 0;
}