From: Gerald Fontenay <gvfontenay@lbl.gov>
To: pgsql-performance@postgresql.org
Subject: Re: Strange explain on partitioned tables
Date: Fri, 23 Jul 2010 23:29:37 -0700
Message-ID: <4C4A8851.3090608@lbl.gov> (raw)
In-Reply-To: <1279923370.9866.37.camel@jd-desktop.unknown.charter.com>
References: <4C47F8C8.10005@edd.fr>
<4C484874.3060609@2ndquadrant.com>
<4C4A11CB.6040800@lbl.gov>
<1279923370.9866.37.camel@jd-desktop.unknown.charter.com>
Joshua D. Drake wrote:
> On Fri, 2010-07-23 at 15:03 -0700, Gerald Fontenay wrote:
>
>>> The PostgreSQL partitioning system is aimed to support perhaps a
>>> hundred inherited tables. You can expect to get poor performance on
>>> queries if you create 1000 of them.
>>>
>> Hi,
>>
>> Why is that you would expect poor performance for say 1000 or more? I
>> have a ~1000 inherited tables and I don't see any significant slowdowns.
>> I only ever access a single inherited table at a time though in this
>> situation. I suppose I am using inheritance only for organization in
>> this case...
>>
>
> It is variable based on workload and as I recall has to do with the
> planning time. As the number of children increases, so does the planning
> time.
>
>
I do not execute queries against the parent and children tables.
It became obvious that this can be quite slow.
I am asking specifically if I can expect problems in *that* situation, again, where I directly query a single child table only and where I may have thousands. Just like a any other single table query, no?
Thank you,
Gerald
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To: pgsql-performance@postgresql.org
Cc: gvfontenay@lbl.gov
Subject: Re: Strange explain on partitioned tables
In-Reply-To: <4C4A8851.3090608@lbl.gov>
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