From: Tom Lane <tgl@sss.pgh.pa.us>
To: Michael van Rooyen <michael@loot.co.za>
Cc: pgsql-performance@postgresql.org
Subject: Re: Slow queries on 9.3.1 despite use of index
Date: Mon, 28 Apr 2014 13:50:20 -0400
Message-ID: <23166.1398707420@sss.pgh.pa.us> (raw)
In-Reply-To: <535E8BFF.1010503@loot.co.za>
References: <535E8BFF.1010503@loot.co.za>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
Michael van Rooyen <michael@loot.co.za> writes:
> I'm trying to get to the bottom of a performance issue on a server
> running PostgreSQL 9.3.1 on Centos 5.
Hm ... it seems pretty suspicious that all of these examples take just
about exactly 1 second longer than you might expect. I'm wondering
if there is something sitting on an exclusive table lock somewhere,
and releasing it after 1 second.
In particular, this looks quite a bit like the old behavior of autovacuum
when it was trying to truncate empty pages off the end of a relation ---
it would hold off other accesses to the table until deadlock_timeout
elapsed, whereupon it'd get kicked off the exclusive lock (and have to
retry the truncation next time). Are you *sure* this server is running
9.3.1, and not something pre-9.3?
regards, tom lane
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
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: tgl@sss.pgh.pa.us, michael@loot.co.za
Subject: Re: Slow queries on 9.3.1 despite use of index
In-Reply-To: <23166.1398707420@sss.pgh.pa.us>
* 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