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Re: Adding foreign key performance

From: Jeff <threshar(at)torgo(dot)978(dot)org>
To: Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au>
Cc: sszabo(at)megazone(dot)bigpanda(dot)com, pgsql-performance(at)postgresql(dot)org
Subject: Re: Adding foreign key performance
Date: 2003-10-29 14:01:54
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Lists: pgsql-performance
On Wed, 29 Oct 2003 09:47:28 +0800
Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> wrote:

> >>Just loaded up delicious 7.4b5 and wow...
> >>
> >>sort_mem 8192:  137038ms [lots of tmp file activity]
> >>sort_mem 256000: 83109ms
> > 

> 1. A full ANALYZE
> 2. A delete all from pg_statistic
I had previously analyze'd before I ran those numbers.
But I did it again with and without stats. 

Run 1 Time: 80157.21 ms
Run 2 Time: 80763.59 ms

Killed statistics:

Time: 80571.71 ms
Time: 80759.18 ms

Chances are it is going to seq scan regardless so the stats are rather
useless.  Perhaps in other scenarios it would help.

Jeff Trout <jeff(at)jefftrout(dot)com>

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