Greg Smith <greg@xxxxxxxxxxxxxxx> writes: > and the query optimizer needs to be careful about what it does and > doesn't pull from disk. If that's not the case, like here where there's > 8GB of RAM and a 7GB database, dramatic reductions to both seq_page_cost > and random_page_cost can make sense. Don't be afraid to think lowering > below 1.0 is going too far--something more like 0.01 for sequential and > 0.02 for random may actually reflect reality here. If you are tuning for an all-in-RAM situation, you should set random_page_cost equal to seq_page_cost (and usually set both smaller than 1). By definition, those costs are equal if you're fetching from RAM. If it's only mostly-in-RAM then keeping random_page_cost a bit higher makes sense. 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
