|
The following test case
SET optimizer_switch = 'derived_merge=on,in_to_exists=on';
|
|
CREATE TABLE t1 (a INT) ENGINE=MyISAM;
|
INSERT INTO t1 VALUES (4),(8);
|
|
CREATE TABLE t2 (b INT) ENGINE=MyISAM;
|
INSERT INTO t2 VALUES (7),(0);
|
|
CREATE TABLE t3 (c INT, d INT NOT NULL) ENGINE=MyISAM;
|
INSERT INTO t3 VALUES (0,4),(8,6);
|
|
SELECT * FROM t1
|
WHERE a >= ALL (
|
SELECT d FROM t2 LEFT JOIN ( SELECT * FROM t3 ) AS alias ON ( c = b )
|
WHERE b >= a
|
);
|
returns 2 rows:
The same query without the inner subquery returns only one row:
SELECT * FROM t1
|
WHERE a >= ALL ( SELECT d FROM t2 LEFT JOIN t3 ON ( c = b ) WHERE b >= a );
|
a
|
---
|
8
|
A query with a view instead of the inner subquery also returns one row:
CREATE ALGORITHM=MERGE VIEW v AS SELECT * FROM t3;
|
SELECT * FROM t1 WHERE a >= ALL (
|
SELECT d FROM t2 LEFT JOIN v ON ( c = b )
|
WHERE b >= a
|
);
|
a
|
---
|
8
|
CREATE OR REPLACE ALGORITHM=TEMPTABLE VIEW v AS SELECT * FROM t3;
|
SELECT * FROM t1 WHERE a >= ALL (
|
SELECT d FROM t2 LEFT JOIN v ON ( c = b )
|
WHERE b >= a
|
);
|
a
|
---
|
8
|
1 row is the correct result.
branch: maria/5.3
|
revision-id: sergii@pisem.net-20121123121131-p4nfv8j2cbh68dbg
|
date: 2012-11-23 13:11:31 +0100
|
revno: 3605
|
On maria/5.3 the problem appeared with revno 3592 (Merge MariaDB 5.1.66 -> 5.2 -> 5.3).
Also reproducible on maria/5.5, maria/10.0.
MySQL 5.6 returns the correct result.
Minimal optimizer_switch: derived_merge=on,in_to_exists=on
Full optimizer_switch (default):
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on
|
EXPLAIN (with the default optimizer_switch):
EXPLAIN EXTENDED
|
SELECT * FROM t1
|
WHERE a >= ALL (
|
SELECT d FROM t2 LEFT JOIN ( SELECT * FROM t3 ) AS alias ON ( c = b )
|
WHERE b >= a
|
);
|
id select_type table type possible_keys key key_len ref rows filtered Extra
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00 Using where
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 2100.00 Using where
|
2 DEPENDENT SUBQUERY t3 ALL NULL NULL NULL NULL 2100.00 Using where; Using join buffer (flat, BNL join)
|
Warnings:
|
Note 1276 Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
|
Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` where <not>(<expr_cache><`test`.`t1`.`a`>(<in_optimizer>(`test`.`t1`.`a`,<exists>(select `test`.`t3`.`d` from `test`.`t2` left join (`test`.`t3`) on((`test`.`t3`.`c` = `test`.`t2`.`b`)) where ((`test`.`t2`.`b` >= `test`.`t1`.`a`) and trigcond((<cache>(`test`.`t1`.`a`) < `test`.`t3`.`d`)))))))
|
Setting it to Minor for now as it can be considered an edge case.
|