Use_count: Wrong count for key error in maria-5.3
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
MariaDB |
Fix Released
|
Medium
|
Igor Babaev |
Bug Description
Not repeatable in maria-5.2, mysql-5.1, mysql-5.5. See also mysql bug #58731. It is best that all such errors are assertions in debug mode.
In the error log:
110621 16:06:04 [Note] Use_count: Wrong count for key at 0x1cdd37f0, 0 should be 1
110621 16:06:04 [Note] Use_count: Wrong count for key at 0x1cdd37f0, 0 should be 1
test case:
CREATE TABLE t1 ( f1 int NOT NULL , f2 int, f3 int, KEY (f3,f2), PRIMARY KEY (f1)) ;
INSERT IGNORE INTO t1 VALUES (19,1,NULL)
SELECT *
FROM t1 AS alias1 STRAIGHT_JOIN t1 AS alias2 ON alias2.f2
WHERE
( alias1.f1 > 238 OR alias1.f2 NOT BETWEEN 238 AND 238 )
AND alias1.f3 != 'y' AND alias1.f2 BETWEEN 238 AND 238 AND
( alias1.f3 = 'u' OR alias1.f1 = 245 );
explain:
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE alias1 range PRIMARY,f3 PRIMARY 4 NULL 1 Using where; Rowid-ordered scan
1 SIMPLE alias2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
bzr version-info:
revision-id: <email address hidden>
date: 2011-06-17 23:00:26 +0200
build-date: 2011-06-21 16:22:30 +0300
revno: 3051
branch-nick: maria-5.3
optimizer_switch:
index_merge=
Changed in maria: | |
milestone: | none → 5.3 |
Changed in maria: | |
status: | New → Confirmed |
importance: | Undecided → Medium |
Changed in maria: | |
status: | Confirmed → In Progress |
Changed in maria: | |
status: | In Progress → Fix Committed |
Changed in maria: | |
status: | Fix Committed → Fix Released |
The bug can be reproduced with all optimizer switches set to OFF.
Slightly simplified example:
CREATE TABLE t1 ( f1 int NOT NULL , f2 int, f3 int, KEY (f3,f2), PRIMARY KEY (f1)) ; ,(20,5, 'r'); ,(20,5, 'r');
INSERT IGNORE INTO t1 VALUES (19,1,NULL)
CREATE TABLE t2 ( f1 int NOT NULL , f2 int, f3 int, KEY (f3,f2), PRIMARY KEY (f1)) ;
INSERT IGNORE INTO t2 VALUES (19,1,NULL)
SELECT * FROM t1, t2
t1.f3 != 'y' AND
t1.f2 BETWEEN 238 AND 238 AND
WHERE (t1.f1 > 238 OR t1.f2 NOT BETWEEN 238 AND 238 ) AND
( t1.f3 = 'u' OR t1.f1 = 245 );