On Wed, Oct 27, 2010 at 1:32 PM, Reid Thompson <Reid.Thompson@xxxxxxxx> wrote: > On Wed, 2010-10-27 at 13:23 -0500, Jon Nelson wrote: >> set it to 500 and restarted postgres. > > did you re-analyze? Not recently. I tried that, initially, and there was no improvement. I'll try it again now that I've set the stats to 500. The most recent experiment shows me that, unless I create whatever indexes I would like to see used *before* the large (first) update, then they just don't get used. At all. Why would I need to ANALYZE the table immediately following index creation? Isn't that part of the index creation process? Currently executing is a test where I place an "ANALYZE foo" after the COPY, first UPDATE, and first index, but before the other (much smaller) updates. .. Nope. The ANALYZE made no difference. This is what I just ran: BEGIN; CREATE TEMPORARY TABLE foo COPY ... UPDATE ... -- 1/3 of table, approx CREATE INDEX foo_rowB_idx on foo (rowB); ANALYZE ... -- queries from here to 'killed' use WHERE rowB = 'someval' UPDATE ... -- 7 rows. seq scan! UPDATE ... -- 242 rows, seq scan! UPDATE .. -- 3700 rows, seq scan! UPDATE .. -- 3100 rows, seq scan! killed. -- Jon -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
