On Wed, Oct 27, 2010 at 12:59 PM, Jon Nelson <jnelson+pgsql@xxxxxxxxxxx> wrote: > On Wed, Oct 27, 2010 at 12:44 PM, Mladen Gogala > <mladen.gogala@xxxxxxxxxxx> wrote: >> On 10/27/2010 1:29 PM, Jon Nelson wrote: >> How big is your default statistics target? The default is rather small, it >> doesn't produce very good or usable histograms. > > Currently, default_statistics_target is 50. I set it to 500 and restarted postgres. No change in (most of) the query plans! The update statement that updates 7 rows? No change. The one that updates 242 rows? No change. 3714? No change. I killed the software before it got to the 1-row-only statements. > I'm not trying creating them after the first UPDATE (which updates > 2.8million of the 10million rows). I mean to say that I (tried) creating the indexes after the first UPDATE statement. This did not improve things. I am now trying to see how creating the indexes before between the COPY and the UPDATE performs. I didn't really want to do this because I know that the first UPDATE statement touches about 1/3 of the table, and this would bloat the index and slow the UPDATE (which should be a full table scan anyway). It's every subsequent UPDATE that touches (at most) 4000 rows (out of 10 million) that I'm interested in. -- Jon -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
