On Jul 28, 11:12 pm, Agustin Henze <[email protected]> wrote:
> El mar, 27-07-2010 a las 16:03 -0700, Graham Dumpleton escribió:
>
> > Please better define 'apache proccesses an unlimited increase'.
>
> Apache processes start to grow without limits[0].

Okay, so the number of processes grows, rather than the amount of
memory used by a process. That is what I wanted to clarify.

> The configuration of
> the VH is:
> WSGIDaemonProcess trac user=www-data group=www-data processes=1
> threads=1 maximum-requests=1000 display-name=wsgi-trac

Do you have WSGIProcessGroup and WSGIApplicationGroup directives in
your configuration as well? Post the more complete configuration.

As is, your graph suggests classic problem of running stuff in
embedded mode with prefork MPM. That is, chance you aren't delegating
Trac to daemon process group properly. See:

  http://blog.dscpl.com.au/2009/03/load-spikes-and-excessive-memory-usage.html

Even if daemon mode used, your use of a single process with single
thread is a bad idea. This is because you can only handle one request
at a time. If for some reason a request blocks or takes a really long
time, then no other requests can be handled at the same time. What
will happen then if using prefork MPM is that Apache will create more
and more Apache server child processes to accept the pending requests,
but they will all block waiting to be able to proxy to daemon process.
Since for prefork MPM the default is 150 processes, you can see as
many as that number of processes created as requests arrive.

As such, if any extensions are thread safe (Trac core is already),
then you should run more than a single thread. If code is still
blocking or taking a long time, those additional threads will still be
able to handle requests. If those all threads get stuck in same way,
then still can have same issue.

if you are not using PHP, you should also change to worker MPM.

BTW, what version of mod_wsgi are you using?

Graham

> Before the actualization from 0.11.7 to 0.12, works with the same
> configuration and didn't happen. I can't reproduce the error and doesn't
> happen very often. But the problem is that when it happens, trac is out
> of service.
>
> [0]http://www.imageno.com/w5wxdsofudqbpic.html
>
> --
> TiN
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