[Zope-Checkins] CVS: ZODB/src/ZODB/tests - PackableStorage.py:1.36
tim.one at comcast.net
Tue Mar 16 18:51:07 EST 2004
Update of /cvs-repository/ZODB/src/ZODB/tests
In directory cvs.zope.org:/tmp/cvs-serv30994/src/ZODB/tests
Bugfix for pack(). Approximately forever, we've seen extremely rare
failures in the ZEO FileStorage pack-while-writing tests, where they die
CorruptedError: ... transaction with checkpoint flag set
By coincidence, the same kind of death during pack() was reported on
zodb-dev today(!). The new checkPackLotsWhileWriting test provokes this
on my box reliably (failed each time it was run).
The problem appears to be that pack's idea of where a FileStorage
ends was obtained merely by seeking to the end of the file. But if
a transaction is in progress, there can be an extra "not really there
yet" transaction at the end of the file, and when either buildPackIndex()
or findReachableFromFuture() bumped into a such a thing, the CorruptedError
above got raised. This is always rare, and was exceedingly rare before
because only one pack per test was tried. The new test tries packing
repeatedly while a thread keeps hammering the database, so is much more
likely to provoke the problem.
The fix amounts to passing FileStorage._pos to the pack code, telling
the latter directly where the legit transactions in the file end.
=== ZODB/src/ZODB/tests/PackableStorage.py 1.35 => 1.36 ===
--- ZODB/src/ZODB/tests/PackableStorage.py:1.35 Fri Mar 12 21:49:22 2004
+++ ZODB/src/ZODB/tests/PackableStorage.py Tue Mar 16 18:51:07 2004
@@ -260,8 +260,7 @@
- # XXX Disabled because it always fails now.
- def XXXcheckPackLotsWhileWriting(self):
+ def checkPackLotsWhileWriting(self):
# This is like the other pack-while-writing tests, except it packs
# repeatedly until the client thread is done. At the time it was
# introduced, it reliably provoked
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