Magnus Hagander <magnus@xxxxxxxxxxxx> writes: > On Wed, Sep 2, 2009 at 00:01, Wei Yan<weiyan1@xxxxxxxxx> wrote: >> Looks like after postgres db server reboot, first query is very slow >> (10+mins). After the system cache built, query is pretty fast. >> Now the question is how to speed up the first query slow issue? > Schedule a run of a couple of representative queries right as the > database has started? That should pre-populate the cache before your > users get there, hopefully. I wonder if VACUUMing his key tables would be a good answer. I bet that a lot of the problem is swapping in indexes in a slow random-access fashion. In recent-model Postgres, VACUUM will do a sequential scan of the indexes (at least for btree) which should be a much more efficient way of bringing them into kernel cache. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
