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Re: Any better plan for this query?..

From: Dimitri <dimitrik(dot)fr(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Simon Riggs <simon(at)2ndquadrant(dot)com>, Merlin Moncure <mmoncure(at)gmail(dot)com>, PostgreSQL Performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Any better plan for this query?..
Date: 2009-05-11 16:22:39
Message-ID: 5482c80a0905110922tf958431ofe468e9c0fd9ac90@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
Hi Tom,

it was not willing :-)
it just stayed so after various probes with a query plan.

Anyway, on 8.4 the default target is 100, an just by move it to 5 I
reached on 16cores  10.500 TPS instead of 8.000 initially. And I think
you have a good reason to keep it equal to 100 by default, isn't it?
;-)

And what about scalability on 32cores?..
Any idea?

Rgds,
-Dimitri

On 5/11/09, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Dimitri <dimitrik(dot)fr(at)gmail(dot)com> writes:
>> Anyone may explain me why analyze target may have so huge negative
>> secondary effect?..
>
> If these are simple queries, maybe what you're looking at is the
> increase in planning time caused by having to process 10x as much
> statistical data.  Cranking statistics_target to the max just because
> you can is not necessarily a good strategy.
>
> 			regards, tom lane
>

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