> default_statistics_target = 100 (tried with 500, no change). Vacuum > analyzed > before initial query, and after each change to default_statistics_target. Modifying the statistics target is useful only if the estimates are seriously off, which is not your case - so it won't help, at least not reliably. > The same query, with a different "ofid", will occasionally get the more > optimal plan -- I assume that the distribution of data is the > differentiator > there. Yes, the difference between costs of the two plans is quite small (11796 vs. 13153) so it's very sensible to data distribution. > Is there any other data I can provide to shed some light on this? You may try to play with the 'cost' constants - see this: http://www.postgresql.org/docs/8.4/interactive/runtime-config-query.html#RUNTIME-CONFIG-QUERY-CONSTANTS You just need to modify them so that the bitmap index scan / bitmap heap scan is prefered to plain index scan. Just be careful - if set in the postgresql.conf, it affects all the queries and may cause serious problems with other queries. So it deserves proper testing ... regards Tomas -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
