On Fri, Apr 3, 2009 at 2:18 AM, rafalak <rafa...@gmail.com> 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 > > > db 8.3.7 > server, atlon dual-core 2,0Ghz, 2GB RAM, SATA > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general > Is the table has indexes? Decreasing the work_mem also increase performance. Monitor these changes by explain the query plan.
Regards, Abbas.
