On Thu, Jan 07, 2010 at 01:38:41PM +0100, Lefteris wrote:
> airtraffic=# EXPLAIN ANALYZE SELECT "DayOfWeek", count(*) AS c FROM
> ontime WHERE "Year" BETWEEN 2000 AND 2008 GROUP BY "DayOfWeek" ORDER
> BY c DESC;
Well, this query basically has to be slow. Correct approach to this
problem is to add precalculated aggregates - either with triggers or
with some cronjob.
Afterwards query speed depends only on how good are your aggregates,
and/or how detailed.
Of course calculating them is not free, but is done on write (or
periodically), and not on user-request, which makes user-requests *much*
faster.
depesz
--
Linkedin: http://www.linkedin.com/in/depesz / blog: http://www.depesz.com/
jid/gtalk: depesz@depesz.com / aim:depeszhdl / skype:depesz_hdl / gg:6749007
