[Zope] high loads, more threads, spinning wheels

[Jens Vagelpohl]

On Apr 25, 2005, at 17:46, Tim Middleton wrote:

>
> I've been doing some simple load tests on a zope application, and I've 
> found
> when i increase the zserver-threads in zope.conf very much the zope 
> server
> goes into some sort of cycle where it eats 100% cpu and refuses to any 
> future
> requests until restarted.

To put it in a very simple way, you should not tweak the threads 
setting unless you really know what you are doing. If your goal is 
performance the usual way of going about that is to run ZEO and add ZEO 
clients as needed.

You're bumping into the very simple fact that there are two items 
interacting badly: Threads and the connections in the Zope database 
connection pool. A thread, under normal circumstances, can only do work 
if it has a connection to work with, and wwill only release the 
connection when the request is finished. There are 7 connections in the 
pool by default.

jens