From: Joshua D. Drake <jd@commandprompt.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Sriram Dandapani <sdandapani@counterpane.com>
Cc: Pgsql-Performance (E-mail) <pgsql-performance@postgresql.org>
Subject: Re: select max(column) from parent table very slow
Date: Thu, 24 Aug 2006 22:16:43 -0700
Message-ID: <44EE87BB.4050104@commandprompt.com> (raw)
In-Reply-To: <18394.1156480407@sss.pgh.pa.us>
References: <6992E470F12A444BB787B5C937B9D4DF057500BF@ca-mail1.cis.local>
<44EE4DA1.5060701@commandprompt.com>
<18394.1156480407@sss.pgh.pa.us>
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
>
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240
Providing the most comprehensive PostgreSQL solutions since 1997
http://www.commandprompt.com/
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: jd@commandprompt.com, tgl@sss.pgh.pa.us, sdandapani@counterpane.com
Subject: Re: select max(column) from parent table very slow
In-Reply-To: <44EE87BB.4050104@commandprompt.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox