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Bug#51494 crash with join, explain and 'sounds like' operator

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The crash happens because of discrepancy between values of
conts_tables and join->const_table_map(make_join_statisctics).
Calculation of conts_tables used condition with
HA_STATS_RECORDS_IS_EXACT flag check. Calculation of
join->const_table_map does not use this flag check.
In case of MERGE table without union with index
the table does not become const table and
thus join_read_const_table() is not called
for the table. join->const_table_map supposes
this table is const and later in make_join_select
this table is used for making&calculation const
condition. As table record buffer is not populated
it leads to crash.
The fix is adding a check if an engine supports
HA_STATS_RECORDS_IS_EXACT flag before updating
join->const_table_map.
This commit is contained in:
Sergey Glukhov
2010-03-19 10:01:02 +04:00
parent 0d608d5b11
commit bed0948145
3 changed files with 29 additions and 1 deletions
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12
mysql-test/r/merge.result
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@ -2286,4 +2286,16 @@ m1 CREATE TABLE `m1` (
DROP TABLE m1;
DROP TABLE `test@1`.`t@1`;
DROP DATABASE `test@1`;
#
# Bug#51494c rash with join, explain and 'sounds like' operator
#
CREATE TABLE t1 (a INT) ENGINE=MYISAM;
INSERT INTO t1 VALUES(1);
CREATE TABLE t2 (b INT NOT NULL,c INT,d INT,e BLOB NOT NULL,
KEY idx0 (d, c)) ENGINE=MERGE;
EXPLAIN SELECT * FROM t1 NATURAL RIGHT JOIN
t2 WHERE b SOUNDS LIKE e AND d = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
DROP TABLE t2, t1;
End of 5.1 tests