Message-ID: <4DFB4C02.3020505@peak6.com>
Date: Fri, 17 Jun 2011 07:43:46 -0500
From: Shaun Thomas <sthomas@peak6.com>
Reply-To: <sthomas@peak6.com>
Organization: Peak6
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To: Svetlin Manavski <svetlin.manavski@gmail.com>
CC: Magnus Hagander <magnus@hagander.net>, <pgsql-performance@postgresql.org>
Subject: Re: seq scan in the case of max() on the primary key column
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On 06/17/2011 06:22 AM, Svetlin Manavski wrote:

> Shaun, that solution is brilliant.

Don't thank me. I actually got the basic idea from a post here a couple 
years ago. The only difference is I formalized it somewhat and put it in 
our utility schema, where I put lots of other random useful stored procs 
I've accumulated over the years. I have another one that works with 
dates. :)

I assume you already modified it by removing the 'utility' schema prefix 
from the recursive call. The recursive call is in case the child tables 
are themselves used as a template for further inheritance. It's rare, 
but possible. This function will always get you the max value on a 
column in a series of partitioned tables, and quickly so long as it's 
indexed.

It's a bit of a hack, but it's worked fine for us while we wait for the 
planner to catch up. :)

-- 
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas@peak6.com

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