Robins Tharakan <robins(dot)tharakan(at)comodo(dot)com> wrote:
> I stumbled upon a situation where the planner comes with a bad
> query plan, but I wanted to mention upfront that I'm using a dated
> PG version and I already see an update which mentions about
> improving planner performance. I just wanted to check if this
> issue is already resolved, and if so, which version should I be
> eyeing.
>
> My PG Version: 8.4.7
> Probably solved in: 8.4.8 / 9.0.4 ?
First off, did you use pg_upgrade from an earlier major release? If
so, be sure you've dealt with this issue:
http://wiki.postgresql.org/wiki/20110408pg_upgrade_fix
Second, the releases you should be considering are on this page:
http://www.postgresql.org/
So 8.4.9, 9.0.5, or 9.1.1.
If anybody recognized the issue from your description, they probably
would have posted by now. The fact that there has been no such post
doesn't necessarily mean it's not fixed -- the description is a
little vague without table definitions and EXPLAIN ANALYZE output,
so people might just not be sure. Since it's arguably in your best
interest to update at least to 8.4.9 anyway, the easiest way to get
your answer might be to do so and test it.
http://www.postgresql.org/support/versioning
> Do let me know if this is a new case. I could try to give you the
> EXPLAIN ANALYSE outputs / approximate table sizes if required.
If you establish that the latest versions of the software still show
the issue, please post with more information, as described here:
http://wiki.postgresql.org/wiki/SlowQueryQuestions
-Kevin