Message-ID: <44EE87BB.4050104@commandprompt.com>
Date: Thu, 24 Aug 2006 22:16:43 -0700
From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
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To: Tom Lane <tgl@sss.pgh.pa.us>
CC: Sriram Dandapani <sdandapani@counterpane.com>,
	"Pgsql-Performance (E-mail)" <pgsql-performance@postgresql.org>
Subject: Re: select max(column) from parent table very slow
References: <6992E470F12A444BB787B5C937B9D4DF057500BF@ca-mail1.cis.local>
	<44EE4DA1.5060701@commandprompt.com>
	<18394.1156480407@sss.pgh.pa.us>
In-Reply-To: <18394.1156480407@sss.pgh.pa.us>
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Tom Lane wrote:
> "Joshua D. Drake" <jd@commandprompt.com> writes:
>> Sriram Dandapani wrote:
>>> Parent table has a column say column1 which is indexed (parent table and
>>> all child tables are indexed on that column)
> 
>> In older versions of postgresql that would scan the whole table. In 8.1 
>> and above it doesn't. However, I am guess that since this is a 
>> partitioned table the planner isn't smart enough to just perform the 
>> query on each child and a max on the set that is returned.
> 
> It is not.  Feel free to submit a patch for planagg.c ...

I think my patch to pgbench may have set your expectations of me a bit 
high ;)...

Joshua D. Drake


> 
> 			regards, tom lane
> 


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