Re: SORT performance - slow?

From: Samuel Gendler <sgendler(at)ideasculptor(dot)com>
To: "Strange, John W" <john(dot)w(dot)strange(at)jpmchase(dot)com>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: SORT performance - slow?
Date: 2011-05-19 21:41:21
Message-ID: BANLkTiniQSV7e-=t5z2+EwH83sWs-8YC4A@mail.gmail.com
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Plus the entire explain analyze output into the form at
http://explain.depesz.com/ and you'll get a nicely human readable output
which shows both the inclusive and exclusive time spent on each step of the
query. It also highlights any steps which show inaccurate statistics. It
will also give you a perma-link which you can use in emails so that everyone
else can see the pretty version, too.

On Thu, May 19, 2011 at 2:13 PM, Strange, John W <
john(dot)w(dot)strange(at)jpmchase(dot)com> wrote:

> Am I reading this right in that the sort is taking almost 8 seconds?
>
>
>
> *"GroupAggregate (cost=95808.09..95808.14 rows=1 width=142) (actual
> time=14186.999..14694.524 rows=315635 loops=1)"*
>
> " Output: sq.tag, sq.instrument, s.d1, s.d2, s.d3, s.d4, s.d5, s.d6, s.d7,
> s.d8, s.d9, s.d10, sum(sq.v)"
>
> " Buffers: shared hit=9763"
>
> *" -> Sort (cost=95808.09..95808.09 rows=1 width=142) (actual
> time=14186.977..14287.068 rows=315635 loops=1)"*
>
> " Output: sq.tag, sq.instrument, s.d1, s.d2, s.d3, s.d4, s.d5, s.d6,
> s.d7, s.d8, s.d9, s.d10, sq.v"
>
> " Sort Key: sq.tag, sq.instrument, s.d1, s.d2, s.d3, s.d4, s.d5,
> s.d6, s.d7, s.d8, s.d9, s.d10"
>
> " Sort Method: quicksort Memory: 79808kB"
>
> " Buffers: shared hit=9763"
>
> *" -> Hash Join (cost=87341.48..95808.08 rows=1 width=142)
> (actual time=6000.728..12037.492 rows=315635 loops=1)"*
>
> " Output: sq.tag, sq.instrument, s.d1, s.d2, s.d3, s.d4, s.d5,
> s.d6, s.d7, s.d8, s.d9, s.d10, sq.v"
>
> " Hash Cond: (s.scenarioid = sq.scenarioid)"
>
> " Buffers: shared hit=9763"
>
>
>
>
>
>
> _______________________________________________________________________________________________
> |* John W. Strange* | Vice President | Global Commodities Technology
> | J.P. Morgan | 700 Louisiana, 11th Floor | T: 713-236-4122 | C:
> 281-744-6476 | F: 713 236-3333
> | john(dot)w(dot)strange(at)jpmchase(dot)com | jpmorgan.com
>
>
>
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