[ZODB-Dev] Re: [Zope-dev] Conflict reduced BTrees for catalogin

[Jeremy Hylton]

> I am working on a CMS on top of ZODB for large amounts of
> large SGML/XML documents.

> To speed things up, a colleague started two import processes
> and we get incredible amounts of "database read conflict error"s
> from cataloguing (although we already use "QueueCatalog" for
> most indexes).

> I think, the data structures used for cataloguing and indexing
> could have a "def _p_independent(self): return 1".

> Does anybody objects?

> If not, I will implement "_p_independent" BTrees and friends.

Conflict resolution for BTrees is very subtle.  I'd like to see a
careful analysis of what impact ignoring read conflicts will have.  It's
definitely impossible for internal nodes, but it might be possible for
buckets.  

Can you prove that ignoring read conflicts is safe?  If you can't, then
I'd say it isn't worth the risk.

Jeremy