Bug #49973 Corrupt partitioned table after concurrent DDL / transactional LOCK TABLE

• Submitted: 29 Dec 2009 11:25
• Modified: 27 May 2010 9:40
• Reporter: Philip Stoev
• Status: Can't repeat
• Category: MySQL Server: Locking
• Severity: S2 (Serious)
• Version: mysql-next-mr-wl3561
• OS: Any
• Assigned to: Ingo Strüwing
• CPU Architecture: Any

[29 Dec 2009 11:25] Philip Stoev

Description:
On two separate occassions, executing a DDL workload that contained transactional LOCK TABLE against the mysql-next-mr-wl3561 tree resulted in a corrupted partitioned table

mysql> select * from t1_part1_N;
ERROR 1194 (HY000): Table 't1_part1_N' is marked as crashed and should be repaired

mysql> repair table t1_part1_N extended;
+---------------------+--------+----------+------------------------------------+
| Table               | Op     | Msg_type | Msg_text                           |
+---------------------+--------+----------+------------------------------------+
| testdb_S.t1_part1_N | repair | warning  | Number of rows changed from 1 to 0 |
| testdb_S.t1_part1_N | repair | warning  | Number of rows changed from 3 to 0 |
| testdb_S.t1_part1_N | repair | status   | OK                                 |
+---------------------+--------+----------+------------------------------------+
3 rows in set (0.00 sec)

In other words, the table contained some rows, but after repair, it is now empty.

The datadir shows some files of zero length:

[philips@fedora10 testdb_S]$ ls -la | grep t1_part1
-rw-rw---- 1 philips philips 8636 2009-12-29 12:01 t1_part1_N.frm
-rw-rw---- 1 philips philips   28 2009-12-29 12:01 t1_part1_N.par
-rw-rw---- 1 philips philips    0 2009-12-29 12:01 t1_part1_N#P#p0.MYD
-rw-rw---- 1 philips philips 1024 2009-12-29 12:01 t1_part1_N#P#p0.MYI
-rw-rw---- 1 philips philips    0 2009-12-29 12:01 t1_part1_N#P#p1.MYD
-rw-rw---- 1 philips philips 1024 2009-12-29 12:01 t1_part1_N#P#p1.MYI

How to repeat:
If this is consistently repeatable, a simplified test case will be uploaded. In the meantime, the datadir will be made available for examination.

[29 Dec 2009 11:35] Philip Stoev

Datadir, containing the corrupt table before repair:

http://mysql-systemqa.s3.amazonaws.com/var-bug49973.zip

[27 May 2010 9:40] Ingo Strüwing

This had been reported against a former attempt to backport WL#3561.
It does no longer belong to any existing software any more.
In similar tests against the new backport this hasn't been seen again.