[ZODB-Dev] ZODB-level indexing

[Jeremy Hylton]

On Wed, 2003-11-05 at 11:05, Roché Compaan wrote:
> QueuedCatalog only addresses performance hits suffered while objects are
> indexed. You still end up with a lot of unnecessary invalidations being
> pushed to clients.

It does reduce the number of invalidations, because you can batch
operations.  You're right that this isn't the primary effect.

> > The drawback is that the catalog is a little bit out of sync with the
> > content.  You get improved performance and the cost of reduced
> > consistency.
> 
> We need up-to-date indexes most of the time.

Which is at odds with using QueueCatalog to reduce the number of
invalidations :-).

> This sounds like a very workable idea and without the complication of
> trying to integrate this with a ZODB storage. I doubt if a typical ZEO
> setup will benefit from this because there is still a round trip from
> client to server.

A typical ZEO setup might benefit.  You may get better performance from
an indexing server, because you let the app servers focus on doing
everything else.  There's less cache contention between content and
index data, and less work for the app servers because they're no
re-loading index data all the time.

Jeremy