[ZODB-Dev] Re: BTrees strangeness (was [Zope-dev] Zope 2.X BIGSession problems - blocker - our site dies - need help of experienceZope developer, please)

[Tim Peters]

[Chris McDonough]
> ...
> I'd really rather just figure out why the code is failing in the
> first place.  I'd just rather not mask the problem until I understand
> the cause.  That may never happen, of course, but a man can dream.

I definitely want to know it if there's still a way remaining to provoke
conflict resolution into creating insane BTrees, although I only care if
it's a most-recent version of ZODB (3.1.5, 3.2.1, or HEAD) (earlier versions
have known, relevant bugs that have been fixed).

BTrees appear sensitive to tiny timing holes just because they're
complicated data structures and are involved in conflict resolution a lot.
But apart from the bugs in the BTree implmentation fixed a loooong time ago,
no other "corruption bug" we've squashed since then actually had anything to
do with BTrees -- they were general timing holes that could corrupt anything
at all involved in conflict resolution (generally hard-to-provoke failure of
invalidation to keep caches consistent).