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| author | unknown <gkodinov/kgeorge@magare.gmz> | 2007-08-28 18:51:03 +0300 |
|---|---|---|
| committer | unknown <gkodinov/kgeorge@magare.gmz> | 2007-08-28 18:51:03 +0300 |
| commit | 310afbd4a96baeedc7202a3b2cac7860c76d83e2 (patch) | |
| tree | a6f10748580275e7b10aa99d7f88d2a5e1f10d02 /mysql-test/r/status.result | |
| parent | 42aa480b4345aa920e0ff60001b09eb52c9c04c5 (diff) | |
| download | mariadb-git-310afbd4a96baeedc7202a3b2cac7860c76d83e2.tar.gz | |
Bug #30377: EXPLAIN loses last_query_cost when used with UNION
Currently the Last_query_cost session status variable shows
only the cost of a single flat subselect. For complex queries
(with subselects or unions etc) Last_query_cost is not valid
as it was showing the cost for the last optimized subselect.
Fixed by reseting to zero Last_query_cost when the complete
cost of the query cannot be determined.
Last_query_cost will be non-zero only for single flat queries.
mysql-test/r/status.result:
Bug #30377: test case
mysql-test/t/status.test:
Bug #30377: test case
sql/sql_lex.h:
Bug #30377: helper function
sql/sql_select.cc:
Bug #30377: don't assign cost if not on single level statement
Diffstat (limited to 'mysql-test/r/status.result')
| -rw-r--r-- | mysql-test/r/status.result | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/mysql-test/r/status.result b/mysql-test/r/status.result index ca21b333a6a..36857e22aaf 100644 --- a/mysql-test/r/status.result +++ b/mysql-test/r/status.result @@ -43,3 +43,51 @@ SHOW STATUS LIKE 'max_used_connections'; Variable_name Value Max_used_connections 4 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; |