[Systems] [Fwd: [Systems-logs] Cron <mirrorbrain at sunjammer> ulimit -c unlimited ; mirrorprobe -t 20]

[Sascha Silbe]

Excerpts from Peter Pöml's message of Wed Sep 15 23:46:33 +0200 2010:

> What are these processes? Could you share the output without "|wc -l"?

All entries look like this (with "ps aux|grep mirrorbrain"):

postgres   606  0.0  0.0 106492 13460 ?        Ss   08:16   0:00 postgres: mirrorbrain mirrorbrain 127.0.0.1(50153) idle                                                                     

The PIDs are rapidly increasing (about 2Hz).
There's nothing running as user mirrorbrain and no PostgreSQL processes
running other than those for mirrorbrain and 6 special purpose ones
(autovacuum, wal writer etc.).
Nothing useful in /var/log/postgresql/postgresql-8.3-main.log and
neither in /var/log/syslog.

Where (or as which user) does mirrorbrain run?

> 
> > > -------- Forwarded Message --------
> [...]
> > I'm getting one of these every 5 minutes. Disabling the cron job until
> > we fix the issue.
> 
> 
> What do you get -- the backtrace, shown below, that indicates
> "connection limit exceeded"?

Yes.

> The source is a usage of too many connections (probably about 100, if
> you use the PostgreSQL defaults). I cannot tell you the reason yet. But
> if you can provide details, I will understand it and can tell you more.

Is there anything else you need?
Thanks for looking into it, BTW!


> One thing I can already say. For all cron jobs which are run
> periodically and might not complete within the interval they are
> scheduled for, it is advantagous to run them under a locking wrapper.

At least some cron daemons do not run the same job in parallel if it
takes longer than its frequency. Not sure what Vixie cron does, I would
have to dive into the source (the documentation doesn't specify
behaviour in this case).
However it isn't our problem: The cron job is deactivated and we still
get the same error (at least in the logs - no idea who/where the client
is).

Sascha
-- 
http://sascha.silbe.org/
http://www.infra-silbe.de/
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