Wrong result with hash join and join_cache_level=6
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
MariaDB |
Fix Released
|
Critical
|
Igor Babaev |
Bug Description
In maria-5.3 , the following query:
SELECT STRAIGHT_JOIN t1.f2 FROM t1 JOIN t2 ON t1.f4 = t2.f5 WHERE ( t2.f1 OR t2.f2 ) AND t2.f3 IS NULL ;
returns no rows even though 1 row matches the WHERE predicate and is returned by all other plans.
explain:
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE t2 ref f3 f3 5 const 1 Using where; Using join buffer (flat, BNLH join)
test case:
CREATE TABLE t1 (f2 int(11), f4 varchar(10)) ;
INSERT IGNORE INTO t1 VALUES ('19','
CREATE TABLE t2 (f5 varchar(10), f2 int(11), f1 int(11), f3 int(11), KEY (f3)) ;
INSERT IGNORE INTO t2 VALUES ('time'
SET SESSION join_cache_level=6;
SET SESSION optimizer_
SELECT STRAIGHT_JOIN t1.f2 FROM t1 JOIN t2 ON t1.f4 = t2.f5 WHERE ( t2.f1 OR t2.f2 ) AND t2.f3 IS NULL ;
EXPLAIN SELECT STRAIGHT_JOIN t1.f2 FROM t1 JOIN t2 ON t1.f4 = t2.f5 WHERE ( t2.f1 OR t2.f2 ) AND t2.f3 IS NULL ;
SET SESSION join_cache_level=0;
SET SESSION optimizer_
SELECT STRAIGHT_JOIN t1.f2 FROM t1 JOIN t2 ON t1.f4 = t2.f5 WHERE ( t2.f1 OR t2.f2 ) AND t2.f3 IS NULL ;
Even though this particular test case includes join_cache_bka=off, the problematic query plan was also observed without having to force it.
Changed in maria: | |
status: | New → Confirmed |
importance: | Undecided → Critical |
Changed in maria: | |
status: | Confirmed → In Progress |
Changed in maria: | |
status: | In Progress → Fix Committed |
Changed in maria: | |
status: | Fix Committed → Fix Released |
bzr version-info:
revision-id: <email address hidden>
date: 2010-12-25 18:54:14 -0800
build-date: 2010-12-26 12:03:40 +0200
revno: 2871
branch-nick: maria-5.3