2009/9/14 <tv@fuzzy.cz>:
> It seems there's something very wrong - the plans are "equal" but in the
> first case the results (actual time) are multiplied by 100. Eithere there
> is some sort of cache (so the second execution is much faster), or the
> system was busy during the first execution, or there is something wrong
> with the hardware.
I think you should run this query more than twice. If it's slow the
first time and fast every time for many executions after that, then
it's probably just the data getting loaded into the OS cache (or
shared buffers). If it's bouncing back and forth between fast and
slow, you might want to check whether your machine is swapping.
It might also be helpful to post all the uncommented settings from
your postgresql.conf file.
...Robert