From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dave Cramer <pg@fastcrypt.com>
Cc: pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: performance regression with 9.2
Date: Thu, 15 Nov 2012 14:21:13 -0500
Message-ID: <20478.1353007273@sss.pgh.pa.us> (raw)
In-Reply-To: <CADK3HHKA-JAs1Bno4=_956NnAoNZars60qU0PBiX7-gOnWnEaQ@mail.gmail.com>
References: <CADK3HHKA-JAs1Bno4=_956NnAoNZars60qU0PBiX7-gOnWnEaQ@mail.gmail.com>
Dave Cramer <pg@fastcrypt.com> writes:
> This query is a couple orders of magnitude slower the first result is
> 9.2.1, the second 9.1
Thanks for sending me the test case off-list. I found the reason why
I'd not been able to reproduce the problem: the index you're hoping it
will use is declared
"note_sets_parent_id_idx" btree (parent_id) WHERE parent_id IS NOT NULL
Apparently 9.2 is less bright than 9.1 about when it can use a partial
index. I'm not sure where I broke that, but will look.
regards, tom lane
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, pg@fastcrypt.com
Subject: Re: performance regression with 9.2
In-Reply-To: <20478.1353007273@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