On Sun, May 21, 2006 at 02:01:14PM -0600, Brendan Duddridge wrote: > When the query planner uses the indexes with the concatenated values > and the where clause, the query can be sub-second response times (but > not always depending on the category_id value). By just doing a > regular join as you suggested, it's always slower. The trick is > getting Postgres to use the proper index all the time. And so far the > only way I can do that is by turning off sequential scans, but that's > something I didn't want to do because I don't know how it would > affect the performance of the rest of my application. You can always disable them for just that query... BEGIN; SET LOCAL enable_seqscan=off; SELECT ... COMMIT; > Just a note, I have random_page_cost set to 1 to try and get it to > favour index scans. The database machine has 8GB of RAM and I have > effective_cache_size set to 2/3 of that. That's rather low for that much memory; I'd set it to 7GB. -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
