From: Robert Haas <robertmhaas@gmail.com>
To: Josh Berkus <josh@agliodbs.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Estimation issue with partitioned tables
Date: Mon, 8 Mar 2010 16:56:03 -0500
Message-ID: <603c8f071003081356p123274cep45ae89f4509e56d4@mail.gmail.com> (raw)
In-Reply-To: <4B93E906.5030804@agliodbs.com>
References: <4B8ACFE7.6040207@agliodbs.com>
<603c8f071003030912k5750abadif64cb36d67ab99ae@mail.gmail.com>
<4B8ED891.7060405@agliodbs.com>
<603c8f071003031807p52f136edh683d19a1d5b46660@mail.gmail.com>
<4B93E906.5030804@agliodbs.com>
On Sun, Mar 7, 2010 at 12:57 PM, Josh Berkus <josh@agliodbs.com> wrote:
>>> Yeah, I can generate one pretty easily; the behavior is readily
>>> observable and repeatable. Will get on it RSN, but at you said, we're
>>> not doing anything about it for 9.0.
>
> Well, I can generate a test case, but on examination it turns out to be
> nothing to do with partitioning; it's just good old "n-distinct
> underestimation", and not really related to partitioning or joins.
Ah. Well in 9.0 there will be a work around, by me as it happens. :-)
...Robert
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To: pgsql-performance@postgresql.org
Cc: robertmhaas@gmail.com, josh@agliodbs.com
Subject: Re: Estimation issue with partitioned tables
In-Reply-To: <603c8f071003081356p123274cep45ae89f4509e56d4@mail.gmail.com>
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