Re: suggestions on improving a query

On Tue, 2007-02-13 at 21:44 -0500, Tom Lane wrote:
> Rajarshi Guha <rguha(at)indiana(dot)edu> writes:
> > However the clause:
> > dock.target = '1YC1' and
> > dock.dockid = dockscore_plp.id
> > reduces the number of rows from 4.6M to 96K.
>
> The planner seems to be estimating about ten times that many. Perhaps
> increasing the statistics target for dock.target would help?

My original message had a typo: I expected that it should ~ 960K, so
postgres is working as expected.

However increasing the statistics target for dock.target did lead to an
improvement in performance. Could this be because dock.target has only 5
unique values? So though the table has ~4.6M rows, each set of ~960K
rows for dock.dockid is associated with a single value of dock.target.

Thanks,

-------------------------------------------------------------------
Rajarshi Guha <rguha(at)indiana(dot)edu>
GPG Fingerprint: 0CCA 8EE2 2EEB 25E2 AB04 06F7 1BB9 E634 9B87 56EE
-------------------------------------------------------------------
All great ideas are controversial, or have been at one time.