Bug #4877 Concurrent SELECT and ALTER TABLE deadlocks Merge table
Submitted: 3 Aug 2004 18:20 Modified: 6 Aug 2004 1:53
Reporter: Bill Taylor Email Updates:
Status: Can't repeat Impact on me:
Category:MySQL Server Severity:S1 (Critical)
Version:4.0.20 OS:Linux (Debian Linux 3.0 r1)
Assigned to: CPU Architecture:Any

[3 Aug 2004 18:20] Bill Taylor
Deadlock has been seen several times between a SELECT and a UNION changing ALTER TABLE on a MyISAM merge table.

This may be related to bug 2408, but there is definitely only 1 thread issuing ALTER TABLE.

How to repeat:
We have not been able to reproduce this reliably but see it freqently.

Set up a merge table as a union of partitions. Issue an ALTER TABLE to change the union to add a new table and remove an old one.

At the same time issue a SELECT on the merge table. (We have not been able to ascertain which is actually starting first)
[6 Aug 2004 1:53] MySQL Verification Team
Not enough information was provided for us to be able
to handle this bug. Please re-read the instructions at

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to this bug and change the status back to 'Open'.

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