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From Mladen Turk <>
Subject Re: Events, Destruction and Locking
Date Tue, 07 Jul 2009 05:56:53 GMT
Paul Querna wrote:
> Can't sleep, so finally writing this email I've been meaning to write
> for about 7 months now :D
> Pools don't help, but don't really make it worse, and are good enough
> for the actual cleanup part -- the difficultly lies in knowing *when*
> you can cleanup an object.

Pool pre cleanup is meant to deal with such issues.
You register a pre-cleanup and it will run before any of the
pool objects are actually destroyed.

In your case pre-cleanup callback could break the wait loop
and make sure you don't reference a zombie object.
The only issue left is guarding thread access to a singleton
pollset interrupt (we even have pollset_interrupt with latest APR)
from a pre-cleanup callback (or simply using a queue to serialize
the objects that needs to get removed from the pollset)

The exact problem we have/had with Tomcat native where shutting
down the server can lead to JVM crash in case the connections
are still in the pool waiting for the network event to happen.


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