On Fri, Jul 08, 2005 at 12:04:07PM -0400, Stephen Bowman wrote:
>
> Clearly it needs to use the index =)
Indeed -- now to figure out why the estimates for index scans are
so high. The row count estimates are almost spot-on, so that's not
it. What are your settings for the following configuration variables?
shared_buffers
random_page_cost
effective_cache_size
cpu_tuple_cost
cpu_index_tuple_cost
How much RAM do you have? Have you set shared_buffers and
effective_cache_size accordingly? The default values are pretty
low for most modern equipment; see the following for tips on
choosing appropriate values:
http://www.powerpostgresql.com/PerfList/
You mentioned that you've analyzed the table, but have you also
vacuumed it recently?
BTW, I should have mentioned earlier that this thread might be
on-topic in pgsql-performance.
--
Michael Fuhr
http://www.fuhr.org/~mfuhr/