Fw: Stalled MySQL process causing high CPU load

["Bruno Prior" <bruno@xxxxxxxxxxxxxxxxx>]

Sorry if two copies of this message end up on the list, but when it didn't
show up after 16 hours, I assumed there was a problem.

Cheers,

Bruno Prior

----- Original Message -----
From: Bruno Prior <bruno@xxxxxxxxxxxxxxxxx>
To: <mysql@xxxxxxxxxxxxxxx>
Sent: Wednesday, November 21, 2001 10:05 PM
Subject: Stalled MySQL process causing high CPU load


> I am a MySQL novice, so there may be a simple explanation for this. But I
> have been unable to find one in the list archives, although several people
> seem to have had similar problems.
>
> I am running MySQL 3.23.36 from the package that comes with Mandrake linux
> 8.0. I am using linux software-RAID mirroring, which required upgrading
the
> kernel to 2.4.6-ac2. The hardware is relatively limited (Duron 800, 128Mb
> RAM), but so are our MySQL requirements. I currently run 2 databases from
> it. One is a home-grown contacts and document management database with
> around 20 tables, none with more than 1,000 records, which I migrated off
MS
> Access 2000. The other is the tables (around 30 or so) required for
> phpgrouware, which I am testing, and consequently have very few records in
> any of the tables.
>
> phpgroupware was the first to be set up, and shortly after I started
> trialling it, I started having a problem with random MySQL processes
> suddenly going into a spin and consuming all the CPU time (around 95%
> according to top), consequently slowing the machine dramatically.
According
> to ps, the stalled process is a sibling of the process whose pid is stored
> in the pid file, but the process does not respond in any way to
mysqladmin.
> the process cannot be killed with mysqladmin or kill, and attempts to
> shutdown the database with mysqladmin or safe-mysql (called from the init
> script) go into a permanent loop. The only way I can get out of it is to
> reboot the server.
>
> What makes this particularly hard to track down is that it often occurs
when
> no one is even using the database. It occurs with both databases, so I
don't
> think it is caused by PHP or MyODBC, which are used to connect to the two
> databases. Nor is the load real - these lockups usually occur when there
is
> little happening on the server, and nothing happening with MySQL. Nor do I
> think it is a lock problem - it has occurred frequently when I have been
the
> only person accessing the server.
>
> To avoid posting all my vital statistics to the mailing list, I have put
the
> output of various mysqladmin commands on our server, in the hope that
> someone might like to take a look to see if I have an obvious problem with
> my configuration. The output of mysqladmin version, extended-status,
> variables and processlist are on http://www.summerleaze.co.uk respectively
> at /mysql-vers.txt, /mysql-status.txt, /mysql-vars.txt and /mysql-process.
>
> I hope I have provided sufficient information. Does anyone have any idea
> what might be causing this?
>
> Cheers,
>
> Bruno Prior
> bruno@xxxxxxxxxxxxxxxxx
>
>


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