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Merge magare.gmz:/home/kgeorge/mysql/work/B30377-5.0-opt

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into  magare.gmz:/home/kgeorge/mysql/work/B30377-5.1-opt
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gkodinov/kgeorge@magare.gmz
2007-08-29 11:38:05 +03:00
parent 2df0485d93 cfaa0983c8
commit acf0ebe69f
4 changed files with 107 additions and 1 deletions
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48
mysql-test/r/status.result
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@ -87,6 +87,54 @@ SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME LIKE 'max_us
VARIABLE_NAME VARIABLE_VALUE VARIABLE_NAME VARIABLE_VALUE
MAX_USED_CONNECTIONS 4 MAX_USED_CONNECTIONS 4
SET GLOBAL thread_cache_size=@save_thread_cache_size; SET GLOBAL thread_cache_size=@save_thread_cache_size;
CREATE TABLE t1 ( a INT );
INSERT INTO t1 VALUES (1), (2);
SELECT a FROM t1 LIMIT 1;
a
1
SHOW SESSION STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 2.402418
EXPLAIN SELECT a FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
SHOW SESSION STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 2.402418
SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a;
a
1
2
SHOW SESSION STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 0.000000
EXPLAIN SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
2 UNION t1 ALL NULL NULL NULL NULL 2
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL Using filesort
SHOW SESSION STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 0.000000
SELECT a IN (SELECT a FROM t1) FROM t1 LIMIT 1;
a IN (SELECT a FROM t1)
1
SHOW SESSION STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 0.000000
SELECT (SELECT a FROM t1 LIMIT 1) x FROM t1 LIMIT 1;
x
1
SHOW SESSION STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 0.000000
SELECT * FROM t1 a, t1 b LIMIT 1;
a a
1 1
SHOW SESSION STATUS LIKE 'Last_query_cost';
Variable_name Value
Last_query_cost 4.805836
DROP TABLE t1;
show status like 'com_show_status'; show status like 'com_show_status';
Variable_name Value Variable_name Value
Com_show_status 3 Com_show_status 3

32
mysql-test/t/status.test
View File

@ -186,6 +186,38 @@ disconnect con3;
disconnect con2; disconnect con2;
disconnect con1; disconnect con1;
#
# Bug #30377: EXPLAIN loses last_query_cost when used with UNION
#
CREATE TABLE t1 ( a INT );
INSERT INTO t1 VALUES (1), (2);
SELECT a FROM t1 LIMIT 1;
SHOW SESSION STATUS LIKE 'Last_query_cost';
EXPLAIN SELECT a FROM t1;
SHOW SESSION STATUS LIKE 'Last_query_cost';
SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a;
SHOW SESSION STATUS LIKE 'Last_query_cost';
EXPLAIN SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a;
SHOW SESSION STATUS LIKE 'Last_query_cost';
SELECT a IN (SELECT a FROM t1) FROM t1 LIMIT 1;
SHOW SESSION STATUS LIKE 'Last_query_cost';
SELECT (SELECT a FROM t1 LIMIT 1) x FROM t1 LIMIT 1;
SHOW SESSION STATUS LIKE 'Last_query_cost';
SELECT * FROM t1 a, t1 b LIMIT 1;
SHOW SESSION STATUS LIKE 'Last_query_cost';
DROP TABLE t1;
# End of 5.0 tests # End of 5.0 tests
# #

22
sql/sql_lex.h
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@ -1799,6 +1799,28 @@ typedef struct st_lex : public Query_tables_list
bool table_or_sp_used(); bool table_or_sp_used();
bool is_partition_management() const; bool is_partition_management() const;
/**
@brief check if the statement is a single-level join
@return result of the check
@retval TRUE The statement doesn't contain subqueries, unions and
stored procedure calls.
@retval FALSE There are subqueries, UNIONs or stored procedure calls.
*/
bool is_single_level_stmt()
{
/*
This check exploits the fact that the last added to all_select_list is
on its top. So select_lex (as the first added) will be at the tail
of the list.
*/
if (&select_lex == all_selects_list && !sroutines.records)
{
DBUG_ASSERT(!all_selects_list->next_select_in_list());
return TRUE;
}
return FALSE;
}
} LEX; } LEX;
struct st_lex_local: public st_lex struct st_lex_local: public st_lex

4
sql/sql_select.cc
View File

@ -4505,7 +4505,11 @@ choose_plan(JOIN *join, table_map join_tables)
/* /*
Store the cost of this query into a user variable Store the cost of this query into a user variable
Don't update last_query_cost for statements that are not "flat joins" :
i.e. they have subqueries, unions or call stored procedures.
TODO: calculate a correct cost for a query with subqueries and UNIONs.
*/ */
if (join->thd->lex->is_single_level_stmt())
join->thd->status_var.last_query_cost= join->best_read; join->thd->status_var.last_query_cost= join->best_read;
DBUG_RETURN(FALSE); DBUG_RETURN(FALSE);
} }