[Mono-list] Thread Pool issues

Gonzalo Paniagua Javier gonzalo.mono at gmail.com
Fri Dec 11 17:09:38 EST 2009

On Fri, 2009-12-11 at 17:00 -0500, Miguel de Icaza wrote:
> Hello,
> > The problem is we have a web service using mod_mono on Apache
> > 2.2.13.  The problem occurs when a lot of simultaneous web requests come in,
> > and/or we spawn a lot of background threads (by "a lot" I mean about 20-25). 
> > At this time, one of our web service threads gets a ThreadAbortException,
> > and httpd's error_log says:
> > "[Tue Nov 24 21:12:21 2009] [error] Maximum number (20) of concurrent
> > mod_mono requests to /tmp/mod_mono_dashboard_default_2.lock reached.
> > Dropping request."
> We recently found a threadpool leak that could cause threads from the
> pool to be leaked and lost forever.   I no longer remember the
> conditions under which this happened.
> The fix is available on 2.6, would you mind testing it?

Miguel, this has nothing to do with that potential leak.

David, that can be fixed by adding this to your apache configuration:

	MonoMaxActiveRequests 0
        MonoMaxWaitingRequests 0

The default setting (which shouldn't be the default, IMO) is 20 active
requests. That makes mod-mono hold or discard any request once there's
20 active ones.


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