From: Robert Haas <robertmhaas@gmail.com>
To: Aaron Guyon <battlemage@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Postgres 8.3, four times slower queries?
Date: Thu, 5 Mar 2009 08:21:56 -0500
Message-ID: <603c8f070903050521q64ea85efnff129b1cb6d5c502@mail.gmail.com> (raw)
In-Reply-To: <f0afbb9b0903041520u25aae965y6abc15d39644eb5b@mail.gmail.com>
References: <f0afbb9b0903021618w616f1158t84dbf119f0b72c70@mail.gmail.com>
<2870.1236050632@sss.pgh.pa.us>
<f0afbb9b0903030931g7b219137n2954cf058d523e52@mail.gmail.com>
<17797.1236119652@sss.pgh.pa.us>
<f0afbb9b0903041520u25aae965y6abc15d39644eb5b@mail.gmail.com>
On Wed, Mar 4, 2009 at 6:20 PM, Aaron Guyon <battlemage@gmail.com> wrote:
> On Tue, Mar 3, 2009 at 5:34 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>
>> Comparisons on
>> numerics aren't terribly fast though (in either release). I wonder
>> whether you could change the key columns to int or bigint.
>
> I changed the affected columns from numeric to integers and I was unable to
> get any performance gain:
> 8.3.3: 1195 ms
> 8.2.12: 611 ms
>
> I've attached the new query plans.
>
>> Are you doing
>> something to force the join order, like running with a small
>> join_collapse_limit setting? If so maybe you shouldn't.
>
> No, we left the join_collapse_limit to the default 8. We tried a higher
> value, but there was no difference in performance.
>
> I'll post the query and the table descriptions in separate messages to the
> list to avoid my mail from being rejected for exceeding the size limit :)
Well, it looks like the problem is that 8.3 is not using the index
idx_bundle_content_bundle_id. But I don't know why that should be
happening, unless there's a problem with that index.
...Robert
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: robertmhaas@gmail.com, battlemage@gmail.com
Subject: Re: Postgres 8.3, four times slower queries?
In-Reply-To: <603c8f070903050521q64ea85efnff129b1cb6d5c502@mail.gmail.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