Sok Ann Yap <sokann@xxxxxxxxx> wrote: > So, index scan wins by a very small margin over sequential scan > after the tuning. I am a bit puzzled because index scan is more > than 3000 times faster in this case, but the estimated costs are > about the same. Did I do something wrong? Tuning is generally needed to get best performance from PostgreSQL. Needing to reduce random_page_cost is not unusual in situations where a good portion of the active data is in cache (between shared_buffers and the OS cache). Please show us your overall configuration and give a description of the hardware (how many of what kind of cores, how much RAM, what sort of storage system). The configuration part can be obtained by running the query on this page and pasting the result into your next post: http://wiki.postgresql.org/wiki/Server_Configuration There are probably some other configuration adjustments you could do to ensure that good plans are chosen. -Kevin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
