On Thu, Apr 2, 2009 at 2:48 PM, rafalak <rafalak@xxxxxxxxx> wrote: > Hello i have big table > 80mln records, ~6GB data, 2columns (int, int) > > if query > select count(col1) from tab where col2=1234; > return low records (1-10) time is good 30-40ms > but when records is >1000 time is >12s > > > How to increse performace ? > > > my postgresql.conf > shared_buffers = 810MB > temp_buffers = 128MB > work_mem = 512MB > maintenance_work_mem = 256MB > max_stack_depth = 7MB > effective_cache_size = 800MB Try lowering random_page_cost close to the setting of seq_page_cost (i.e. just over 1 on a default seq_page_cost) and see if that helps. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
