Re: Possible to improve query plan?

From: Cédric Villemain <cedric(dot)villemain(dot)debian(at)gmail(dot)com>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: Jeremy Palmer <JPalmer(at)linz(dot)govt(dot)nz>, Robert Haas <robertmhaas(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>, "andy(at)squeakycode(dot)net" <andy(at)squeakycode(dot)net>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: Possible to improve query plan?
Date: 2011-01-25 13:44:17
Message-ID: AANLkTimJZqWHVraOX=2_e0UmFyp3Eo6wMB6z8vJPfoQu@mail.gmail.com
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2011/1/25 Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>:
> Jeremy Palmer <JPalmer(at)linz(dot)govt(dot)nz> wrote:
>
>> Kevin I've now clustered the table. And the performance did
>> increase quite a bit.
>
> Yeah, that's enough to notice the difference.
>
>> My only question is how often will I need to re-cluster the table,
>> because it comes at quite a cost. The setup I'm running will mean
>> that 10,000 new rows will be inserted, and 2,500 rows will be
>> updated on this table each day.
>
> You're going to see performance drop off as the data fragments.
> You'll need to balance the performance against maintenance
> down-time.  I would guess, though, that if you have a weekly
> maintenance window big enough to handle the CLUSTER, it might be
> worth doing it that often.

Was FILLFACTOR already suggested regarding the INSERT vs UPDATE per day ?

http://www.postgresql.org/docs/9.0/static/sql-altertable.html (and
index too, but they already have a default at 90% for btree)

>
> -Kevin
>
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--
Cédric Villemain               2ndQuadrant
http://2ndQuadrant.fr/     PostgreSQL : Expertise, Formation et Support

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