From: Ken Geis <kgeis@speakeasy.org>
To: Bruno Wolff III <bruno@wolff.to>
Cc: pgsql-performance@postgresql.org
Subject: Re: bad estimates / non-scanning aggregates
Date: Thu, 28 Aug 2003 20:00:32 -0700
Message-ID: <3F4EC1D0.5010503@speakeasy.org> (raw)
In-Reply-To: <20030829030156.GF4373@wolff.to>
References: <3F4E99F7.7080604@speakeasy.org>
<20030829025109.GD4373@wolff.to>
<3F4EBF7E.8020602@speakeasy.org>
<20030829030156.GF4373@wolff.to>
Bruno Wolff III wrote:
>>Not according to the optimizer! Plus, this is not guaranteed to return
>>the correct results.
>
> For it to be fast you need an index on (stock_id, price_date) so that
> you can use an index scan.
I already said that such an index existed. In fact, it is the primary
key of the table. And yes, I *am* analyzed!
> The answers are guarenteed to be correct. See:
> http://developer.postgresql.org/docs/postgres/sql-select.html#SQL-DISTINCT
That's good to know. Thanks!
Ken
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To: pgsql-performance@postgresql.org
Cc: kgeis@speakeasy.org, bruno@wolff.to
Subject: Re: bad estimates / non-scanning aggregates
In-Reply-To: <3F4EC1D0.5010503@speakeasy.org>
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