I have a problem where I periodically get a python thread that never dies by itself, or dies only after 8+ hours. I have tried to mitigate the problem by limiting memory and CPU usage of any individual python thread on my Linux box; it works to a point. A very small point ;) It does prevent these hangs from completely stopping site use, but it also prevents the site running as fast as it could at other times. I am pretty sure that one of two products is the culprit here: ZMySQLDA-2.0.8 (latest stable release) ExtFile-1.1.3 (ExtFile 1.2.0 has since been released with some issues reported on this list) The server experiencing the problem is running Redhat Linux 7.2, Zope 2.5.1, and Python 2.1.3. I have some very large files which are stored as ExtFile objects that my users download via HTTP access at the moment (some 100+ MB). Also, 90% of my website content is dynamically derived from the MySQL database. There are roughly 1000 users that use the site consistently throughout each day. I had found a post (or an archive on the zope.org site) a few weeks ago about a way to debug python threads or to watch a live traceback of threads through some debugging method in order to debug products, but I can't find it again now. I am probably using the wrong search terms this time around. Anyhow, hoping someone knows a way to trace the problem back to the product responsible for the thread hangs (assuming it isn't a problem with either the version of Zope or the version of Python that I am using). Thanks for any help, Ryan