From: Jeff Frost <jeff@frostconsultingllc.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: Index usage problem on 8.3.3
Date: Thu, 30 Oct 2008 18:22:19 -0700
Message-ID: <490A5DCB.9060403@frostconsultingllc.com> (raw)
In-Reply-To: <14519.1225415657@sss.pgh.pa.us>
References: <490A4EBE.9030804@frostconsultingllc.com>
<13272.1225413116@sss.pgh.pa.us>
<490A56C1.8020804@frostconsultingllc.com>
<14519.1225415657@sss.pgh.pa.us>
Tom Lane wrote:
> Okay. What that means is that the indexes were created on data that had
> already been inserted and updated to some extent, resulting in
> HOT-update chains that turned out to be illegal for the new indexes.
> The way we deal with this is to mark the indexes as not usable by any
> query that can still see the dead HOT-updated tuples.
>
> Your best bet for dodging the problem is probably to break the operation
> into two transactions, if that's possible. INSERT and UPDATE in the
> first xact, create the indexes at the start of the second. (Hmm ...
> I'm not sure if that's sufficient if there are other concurrent
> transactions; but it's certainly necessary.) Another possibility is
> to create the indexes just after data load, before you start updating
> the columns they're on.
>
>
Thanks Tom!
Any idea why I don't see it on 8.3.4?
--
Jeff Frost, Owner <jeff@frostconsultingllc.com>
Frost Consulting, LLC http://www.frostconsultingllc.com/
Phone: 916-647-6411 FAX: 916-405-4032
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: jeff@frostconsultingllc.com, tgl@sss.pgh.pa.us
Subject: Re: Index usage problem on 8.3.3
In-Reply-To: <490A5DCB.9060403@frostconsultingllc.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