A followup to my own post. We are still having problems, but we have some new information:
We tried activating the debug_log once, using instructions obtained from a message posted to this list. Unfortunately, that was the attempt wherein Zope ran for half an hour under heavy load with no problem.
Our server got hung up again, last night at 3:42am. But this time, I had the debug log running. The result may be interesting to somebody, but I don't think I know enough to interpret it. The last two entries in Z2.log are: aaa.bbb.ccc.ddd - - [13/Dec/1999:03:42:50 -0500] "GET /SRF/images/srflogo64 HTTP/1.0" 200 18236 "http://www.sourcegear.com/SRF" "Mozilla/4.7 [en] (WinNT; U)" aaa.bbb.ccc.ddd - - [13/Dec/1999:03:42:51 -0500] "GET /SRF/images/srfad HTTP/1.0" 200 49994 "http://www.sourcegear.com/SRF" "Mozilla/4.7 [en] (WinNT; U)" and those entries seem to be reflected properly in the debug.log file: B 143352400 1999-12-13T03:42:50 GET /SRF/images/srflogo64 I 143352400 1999-12-13T03:42:50 0 B 144071968 1999-12-13T03:42:50 GET /SRF/images/srfad I 144071968 1999-12-13T03:42:50 0 A 143352400 1999-12-13T03:42:50 200 18236 E 143352400 1999-12-13T03:42:50 A 144071968 1999-12-13T03:42:50 200 49994 E 144071968 1999-12-13T03:42:51 The debug.log file has an obvious pattern. Every web server hit seems to generate four entries in the file, each with a different letter at the beginning of the line: B, I, A, and E. I'm speculating that these entries correspond to four stages of serving the transaction, and that the B and E probably refer to Beginning and End. There are no further entries in Z2.log, but there are LOTS of subsequent entries in debug.log. The first few look like this: B 143461304 1999-12-13T03:43:04 GET /robots.txt I 143461304 1999-12-13T03:43:04 0 B 143095944 1999-12-13T03:43:10 GET /Store I 143095944 1999-12-13T03:43:10 0 B 143514056 1999-12-13T03:44:59 GET /SOS I 143514056 1999-12-13T03:44:59 0 and that remains the pattern for the remainder of the debug.log file. Every attempted web transaction generates a B line and an I line, but there is never an A or E line. It appears interesting to note that the first failed transaction attempt was a fetch of /robots.txt, but I think that's a coincidence. We do not have a robots.txt file on our site right now, but there are lots of other occurrences in the log files of attempts to fetch that file, returning the 404 properly. Any ideas? -- Eric W. Sink, Software Craftsman SourceGear Corporation eric@sourcegear.com