| From: | Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com> |
|---|---|
| To: | Ang Chin Han <angch(at)bytecraft(dot)com(dot)my> |
| Cc: | Rhaoni Chiu Pereira <rhaoni(at)sistemica(dot)info>, PostgreSQL Performance <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Query too slow |
| Date: | 2003-08-26 15:47:52 |
| Message-ID: | 20030826084326.M30963-100000@megazone.bigpanda.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On Tue, 26 Aug 2003, Ang Chin Han wrote:
> Stephan Szabo wrote:
>
> > Looking at the explain:
>
> Veering aside a bit, since we usually pinpoint performance problems by
> looking at EXPLAIN ANALYZE's differences between the planner's
> estimation and actual execution's stats, what's involved in parsing the
> EXPLAIN ANALYZE results, and highlighting the places where they are way
> different? Bold, underline, or put some asterisks in front of those steps.
The hardest part is determining where it matters I think. You can use the
row counts as the base for that, but going from 1 row to 50 is not
necessarily going to be an issue, but it might be if a nested loop is
chosen.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2003-08-26 16:01:32 | Re: Query too slow |
| Previous Message | JM | 2003-08-26 13:42:52 | Best tweak for fast results.. ? |