From: pasman pasmański <pasman.p@gmail.com>
To: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Why we don't want hints Was: Slow count(*) again...
Date: Sun, 5 Jun 2011 16:25:39 +0100
Message-ID: <BANLkTimE3isrTRmZFG8obsvYJCUxSmJzaA@mail.gmail.com> (raw)
In-Reply-To: <AANLkTimjt7PGuSyXFsedjCsANzMiVYNDfUUaPJ6_wqrr@mail.gmail.com>
References: <4D53CA4F020000250003A789@gw.wicourts.gov>
<201102162122.p1GLMQS29138@momjian.us>
<AANLkTimjt7PGuSyXFsedjCsANzMiVYNDfUUaPJ6_wqrr@mail.gmail.com>
Hi. I have the idea: hints joined to function. For example instead of
WHERE table1.field1=table2.field2
write:
WHERE specificeq(table1.field1,table2.field2)
and hints add to declaration of specificeq function.
2011/2/23, Robert Haas <robertmhaas@gmail.com>:
> On Wed, Feb 16, 2011 at 4:22 PM, Bruce Momjian <bruce@momjian.us> wrote:
>> I am not excited about the idea of putting these correlations in
>> queries. What would be more intesting would be for analyze to build a
>> correlation coeffficent matrix showing how columns are correlated:
>>
>> a b c
>> a 1 .4 0
>> b .1 1 -.3
>> c .2 .3 1
>>
>> and those correlations could be used to weigh how the single-column
>> statistics should be combined.
>
> If you can make it work, I'll take it... it's (much) easier said than
> done, though.
>
> --
> Robert Haas
> EnterpriseDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
>
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--
------------
pasman
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Subject: Re: Why we don't want hints Was: Slow count(*) again...
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