I'm no closer to a solution, but here are some additional data points - all taken on Fedora Core 6.
Postgres 8.1 built from source. Auto vacuum disabled. Create Empty Database. Run our load on the system for 2 hours to populate and exercise the database. Run Vacuum. Takes more than a minute. Run Vacuum immediately again. Takes more than a minute. Reindex the database. Takes 10 seconds. Run Vacuum again. Takes 2 seconds. Allow load to run on the system for 30 minutes. Run Vacuum again. Takes more than a minute. Postgres 8.3 built from source. Auto vacuum disabled. Create Empty Database. Run our load on the system for 2 hours to populate and exercise the database. Run Vacuum. Takes more than a minute. Run Vacuum immediately again. Takes 15 seconds. Run Vacuum immediately again. Takes 15 seconds. Reindex the database. Takes 10 seconds. Run Vacuum again. Takes 2 seconds. So, PostgreSQL 8.3 shows better behaviour, but it is still showing some sort of performance issue which a reindex fixes. And then of course, the kicker is that we can't recreate any of these issues when running the same exact test, on the same exact hardware - but using a different underlying OS. When we were running under a modern Ubuntu, the vacuum never takes more than 2 seconds. We will be checking other OSs soon. I guess if we can't figure out what is causing it, we can at least isolate the distros that we need to tell our customers not to use (or to schedule a reindex if they insist on not upgrading their OS) -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
