[Zope] Performance under load using SQL (Postgresql)

[Mayers, Philip J]

I seem to be able to kill Zope *very* easily (with about 5 requests/sec) if
that request does a lot of SQL activity. Now, this activity is not
avoidable, but that load is pretty puny.

Also, it doesn't just seem to die either - it seems to hang completely under
some circumstances.

I'm using Postgresql (makes no different whether it's 7.0 or the 7.1RC1)
with ZPoPyDA and/or psycopg - they both suffer from the problem. What
happens is that the child threads of ZServer die, leaving me with the
top-level process (doing a waitpid on it's child) and the child (doing a
select on the PCGI socket)

How can I debug this? The machine is plenty fast enough to handle this load,
and with static pages it's fine - just the ones that make SQL calls. Surely
it should degrade gracefully, rather than just *dying*?

Cheers,
Phil