[ZODB-Dev] ZODB cache reimplementation

[Toby Dickenson]

>>Guido is confident that
>>this is safe, assuming, that the keys (oid) don't change their value or
>> hash.
>
>Nice. Ill give it a try.

It was easier than I expected....

Ive updated http://www.zope.org/Members/htrd/cache with a snapshot
that uses weak references. This is my 'Variant A' which is very
similar to Jims proposal.

>These ghosts are always=20
>scanned before the real work can proceed. It is only adding about 6ms to=
 a=20
>worst-case scan, but I think this does justify the complexity of =
weakrefs.

This current revision reduces the duration of a worst case garbage
collection scan to roughly 0.3ms. The memory usage profile is low and
flat, as before.

I wont be needing beer to make me happy tonight ;-)

Toby Dickenson
tdickenson@geminidataloggers.com