[ZODB-Dev] FileStorage: getting rid of tid cache
Jim Fulton
jim at zope.com
Wed Sep 17 10:32:25 EDT 2008
Several years ago, we added a "tid" cache, that cached current
ttransaction ids (tids) for objects. The intent was to speed both
stores and full cache verification. We've since realized that full
verification is a bad idea for databases large enough that caching is
needed. It's not clear how much benefit the cache provides when
storing data.
Recently, we've had multiple serious failures due to memory errors
occurring when the cache became too big. I recently made a change that
makes the errors somewhat less likely to occur (by using a BTree
rather than a dictionary), but the cache can still grow unacceptably
large.
Unless there are strong objections, I'm going to remove the tid cache
in ZODB 3.8.1.
Jim
--
Jim Fulton
Zope Corporation
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