[Maia-users] web pages hang on maia, forced to reboot server. ..

[Robert LeBlanc]

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Kurt Buff wrote:

> Update below - the problem isn't resolved.

- From what you're describing, it sounds like your problem may be with a
corrupt MySQL table or index.  Have you checked your MySQL logs for
indications of any errors?

What happens (disturbingly often, it seems, with MySQL) is that the
bayes_token table gets corrupted--it's the busiest table in the
database, so it's the most likely to get corrupted--and when that
happens MySQL shuts down and tries to restart itself, over and over
again.  What you get is intermittent database connectivity: the
connection attempts that hit the server during the seconds or minutes
that it's alive and running go through, but the ones that arrive while
mysqld is restarting can't connect.

The fact that you're seeing database connection failures from
amavisd-maia, the process-quarantine script, and the PHP scripts all
point to intermittent database failures.  I'd investigate your MySQL
logs, as that seems to be the heart of the problem.

If it does turn out to be a table/index corruption, you can use
mysqldump to salvage what information you can from the affected table
and then drop and recreate the table and reload that data.  If it's any
of the bayes_* tables, though, just drop and recreate all of
them--they'll regenerate on their own over the course of a day or two.
This was discussed a few weeks ago on this list, so there's more advice
on this in the archives if you need it.

As for why tables get corrupted in the first place, that's a matter of
debate.  Some people blame bugs in MySQL, while the MySQL devs claim
InnoDB tables aren't corruptible unless your hardware (disk or RAM) is
faulty.  Personally, I've seen it happen with bad RAM, which causes the
data to be corrupted in the write cache before it's handed to the
filesystem.  Clearly it could also be caused by a faulty drive, but
that's usually much easier to diagnose.

- --
Robert LeBlanc <rjl at renaissoft.com>
Renaissoft, Inc.
Maia Mailguard <http://www.maiamailguard.com/>

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