From: | Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com> |
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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 |
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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.
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