Apologies for the imposing subject line... Briefly, since increasing the NUMBER_OF_THREADS that Zope uses from the default (4) to 20, Zope has been hanging randomly. A request will be sent off to Zope (whether through apache with mod_pcgi, or directly through ZServer), but the request is never served up, and Z2.log shows no record of it. No additional CPU is taken by the python process. Environment: Zope 2.1.3 (source release) python 1.5.2 GCC 2.7.2.3 FreeBSD 3.3-RELEASE The problem was reproducible on pages with framesets, where some of the frame documents are loaded, and one is omitted. It occurs when viewing the management interface, for example (manage_main is displayed, but manage_workspace is not). It seems that only one thread hangs, since other requests continue to be served. Not only frameset pages were affected, though only on frameset pages did the hanging consistently occur. This behaviour was exhibited under minimal load (one or two users), and ceased when I reverted to 4 threads and restarted Zope. Our development machine, running 2.1.4 source, had no such problems when running Zope with 20 threads. I don't recall any drastic changes or checkins between 2.1.3 and 2.1.4, though... (that was basically the /REQUEST traversal security fix) I'll be installing Zope 2.1.6, and try to approximate the the same conditions, but since this is a live machine, it's going to be tricky to find a window of time to perform the switch-over... Anyone out there with some ideas as to the root cause of these hangings, or with similar tales to tell? TIA, -- Marcus