[Python-Dev] bsddb3 test hang (original) (raw)

Tim Peters tim.one@comcast.net
Mon, 21 Jul 2003 22:15:43 -0400

BTW, all the bsddb3 tests people have reported gross problems with (hangs and AssertionErrors) recently come from a group of 8 tests that can be run by themselves, via your platform equivalent of

python ../Lib/bsddb/test/test_thread.py

Add

-v

and unittest will show you the names of the 8 tests as they're running. Add

verbose

and the tests themselves will display a lot about what they're doing.

Since there seem to be timing-related bugs here, trying this on a lot of platforms may help us gather better clues. For example, I was able just once to provoke "a hang" on Win2K when using "-v verbose", by using a debug build of Python, which revealed that it was stuck in an infinite loop in DeadlockWrap, not really hung. Switching options, Python builds, and background loads may all help provoke problems.

I never saw AssertionErrors on Win2K no matter what I did. Fred and Barry did on Linux, though, in the same place Skip reported them. Of (IMO) vital importance is that the assertion details were identical too: in all, the very first (key, value) pair added by writerThread #2 vanished by the time the thread tried to read back all the pairs it wrote. Other AssertionErrors also appeared to be at, or very near, the first (key, value) pair written by a thread.

There's no reason to believe these failures are new, so I wouldn't hold the release for them. But especially on Windows, Berkeley has a rotten reputation (thanks to using the plain broken 1.85 for so many years), and people using bsddb3 in the spambayes Outlook addin are reporting more than their share of seemingly database-related bugs too. The evidence suggests there are still potentially catastrophic bugs in bsddb3!

OTOH, there are no known bugs in ZODB or ZEO. This is because we stopped running their test suites in a loop .