Re: Slower query after psql changed it's execution plan

Romuald Brunet  writes:
> After some investigation, we found out that the PostgreSQL server
> (8.1) changed the execution plan (I'm assuming because the number of
> rows increased).

The problem seems to be that the estimate for the number of rows fetched
from dc_post changed drastically --- it was in the right ballpark, and
now it's off by a factor of 30.  Why is that?  Maybe you had had a
special statistics target setting, and it got dropped?

> The statistics are at the default value everywhere (10)

Almost certainly not enough.

			regards, tom lane