On Thu, Jan 7, 2010 at 4:57 PM, Ivan Voras <ivo...@freebsd.org> wrote: > 2010/1/7 Lefteris <lsi...@gmail.com>: >> On Thu, Jan 7, 2010 at 3:51 PM, Ivan Voras <ivo...@freebsd.org> wrote: >>> On 7.1.2010 15:23, Lefteris wrote: >>> >>>> I think what you all said was very helpful and clear! The only part >>>> that I still disagree/don't understand is the shared_buffer option:)) >>> >>> Did you ever try increasing shared_buffers to what was suggested (around >>> 4 GB) and see what happens (I didn't see it in your posts)? >> >> No I did not to that yet, mainly because I need the admin of the >> machine to change the shmmax of the kernel and also because I have no >> multiple queries running. Does Seq scan uses shared_buffers? > > Everything uses shared_buffers, even things that do not benefit from > it. This is because shared_buffers is the part of the general database > IO - it's unavoidable. >
I will increase the shared_buffers once my kernel is configured and I will report back to you. As for the index scan, I already build an b-tree on year/month but PG (correctly) decides not to use it. The data are from year 1999 up to 2009 (my typo mistake) so it is almost 90% of the data to be accessed. When I ask for a specific year, like 2004 then the index is used and query times become faster. lefteris -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
