"Henrik Steffen" <steffen@city-map.de> writes:
> I have many UPDATEs and INSERTs on my log-statistics. For each
> http-request there will be an INSERT into the logfile. And if
> certain customer pages are downloaded there will even be an UPDATE
> in a customer-statistics table causing a hits column to be set to
> hits+1... I didn't think this was a dramatical change so far.
Just to clarify, INSERT does not create dead rows -- tables that have
lots of INSERTS don't need to be vacuumed particularly often. In
contrast, an UPDATE is really a DELETE plus an INSERT, so it *will*
create dead rows.
To get an idea of how many dead tuples there are in a table, try
contrib/pgstattuple (maybe it's only in 7.3's contrib/, not sure).
> Still sure to run VACUUM ANALYZE on these tables so often?
Well, the ANALYZE part is probably rarely needed, as I wouldn't think
the statistical distribution of the data in the table changes very
frequently -- so maybe run a database-wide ANALYZE once per day? But
if a table is updated frequently, VACUUM frequently is definately a
good idea.
Cheers,
Neil
--
Neil Conway <neilc@samurai.com> || PGP Key ID: DB3C29FC