From: Dieter Maurer <dieter@handshake.de> Arnar Lundesgaard writes:

...

... The problem has been scarily easy to reproduce, and manifests itself whenever multiple persons are working (writing articles etc). As long as only one person is working on the site, it has the expected performance. Not very fast, a few seconds per write operation, but acceptable. However as soon as more people log in and start publishing, we often experience hangs which may last for 10-15 minutes on write operations that usually takes only a few seconds to perform. In this situation Zope doesn't respond to any requests.

Maybe, there are "ConflictError"s. When they occur, Zope automatically restarts the requests. I have some doubts that Zope does it in a way that prevents a new "ConflictError" with high probability. On the other hand, it is not too likely, that the automatic repetition increases the time by almost two orders...

This interests me, I got "ConflictError" log messages when I was trying to use "on-the-fly" generated images in Zope. When a page would request the same image in several different sizes, my server would start thrashing. I never waited 10-15 minutes to find out, but that estimate doesn't surprise me (actually I'm surprised to find that it would recover at all -- I wonder if mine would've done so). This happened often, though not quite everytime (though it was almost certain to happen if I used a new client to view the page -- the browser's cache must've been saving me on the other times). I then put in some code to cause threads to wait if the object was being used (rather clumsily -- I didn't use the threading module, since I hadn't learned about it yet, sigh -- I still have to clear that mess). This reduced the problem considerably, though not quite completely (maybe doing the thread-locking correctly would've solved it completely -- but actually I'm going to try solving it with a solution based on Temp Folders, since I just upgraded Zope, so I may not find out about the original problem). I'm describing this in the hopes that my experience may give you some insight into what might cause this sort of problem, though I'm not sure if it'll help. Good luck, Terry -- ------------------------------------------------------ Terry Hancock hancock@anansispaceworks.com Anansi Spaceworks http://www.anansispaceworks.com P.O. Box 60583 Pasadena, CA 91116-6583 ------------------------------------------------------