database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

MDEV-21102: Server crashes in JOIN_CACHE::write_record_data upon EXPLAIN with subqueries

Browse Source 
JOIN_CACHE has a light-weight initialization mode that's targeted at
EXPLAINs. In that mode, JOIN_CACHE objects are not able to execute.

Light-weight mode was used whenever the statement was an EXPLAIN. However
the EXPLAIN can execute subqueries, provided they enumerate less than
@@expensive_subquery_limit rows.

Make sure we use light-weight initialization mode only when the select is
more expensive @@expensive_subquery_limit.

Also add an assert into JOIN_CACHE::put_record() which prevents its use
if it was initialized for EXPLAIN only.
This commit is contained in:
Sergei Petrunia
2024-03-20 13:09:12 +03:00
parent a618ff2b1c
commit 8cc36fb743
5 changed files with 68 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
mysql-test/main/join_cache.test
View File

@ -4305,6 +4305,27 @@ eval $q2;
DROP TABLE t1,t2,t3,t4;
--echo #
--echo # MDEV-21102: Server crashes in JOIN_CACHE::write_record_data upon EXPLAIN with subqueries and constant tables
--echo #
CREATE TABLE t1 (a int, b int) ENGINE=MyISAM;
CREATE TABLE t2 (c int, d int) ENGINE=MyISAM;
INSERT INTO t2 VALUES (1,10);
CREATE TABLE t3 (e int, key (e)) ENGINE=MyISAM;
INSERT INTO t3 VALUES (2),(3);
--echo # Must not crash, must use join buffer in subquery
EXPLAIN
SELECT * FROM t1
WHERE a > b OR a IN (
SELECT c FROM t2 WHERE EXISTS (
SELECT * FROM t3 t3a JOIN t3 t3b WHERE t3a.e < d
)
);
DROP TABLE t1,t2,t3;
--echo #
--echo # End of 10.4 tests
--echo #