On 3/21/11 3:24 AM, Greg Stark wrote: >> 2-level caches work well for a variety of applications. > > I think 2-level caches with simple heuristics like "pin all the > indexes" is unlikely to be helpful. At least it won't optimize the > average case and I think that's been proven. It might be helpful for > optimizing the worst-case which would reduce the standard deviation. > Perhaps we're at the point now where that matters.
You're missing my point ... Postgres already *has* a 2-level cache: shared_buffers and the FS cache. Anything we add to that will be adding levels. We already did that, actually, when we implemented ARC: effectively gave PostgreSQL a 3-level cache. The results were not very good, although the algorithm could be at fault there. -- -- Josh Berkus PostgreSQL Experts Inc. http://www.pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers