Re: Adding additional index causes 20,000x slowdown for certain select queries - postgres 9.0.3

[Timothy Garnett <tgarnett@xxxxxxxxxxx>]

Thanks, we'll give these a try.

Tim

On Thu, Mar 17, 2011 at 2:13 PM, Kevin Grittner <Kevin.Grittner@xxxxxxxxxxxx> wrote:

Timothy Garnett <tgarnett@xxxxxxxxxxx> wrote:

> We'd still be interested in other suggestions for convincing the
> query planner not to pick the bad plan in this case

You could try boosting cpu_tuple_cost.  I've seen some evidence that
the default number is a bit low in general, so it wouldn't
necessarily be bad to try your whole load with a higher setting.  If
that doesn't work you could set it for the one query.  If that
setting alone doesn't do it, you could either decrease both page
cost numbers or multiply all the cpu numbers (again, probably
boosting cpu_tuple_cost relative to the others).

-Kevin