[ZODB-Dev] PersistentMapping vs OOBTree revisited

[Chris Cioffi]

I know we've talked about this before, but since we now have v3.3 and
maybe a little more benchmarking I thought I'd ask again.

How large does a keyspace have to be to tip the preference from a
PersistentMapping object to a OOBTree?

Right now my rule of thumb as has been that frequently randomly
accessed objects with more than 2000 keys are better as OOBTrees.  For
spaces where I mostly access the object by iterating over the entire
space I leave it as a PersistentMapping until the keyspace grows to
5000+ keys.

My interest is mostly for a standalone ZODB, though I guess the answer
would also apply to Zope as well...

Chris

PS:  Great thanks to the ZODB core developers, I really appreciate
your efforts...storing the objects my code is using as opposed to
having to make a SQL->object mapping has sped up development time
enormously!
-- 
"I was born not knowing and have had only a little time to change that
here and there." -- Richard Feynman