From: Jean-Max Reymond <jmreymond@free.fr>
To: pgsql-performance@postgresql.org
Subject: Performance of UNION vs IN
Date: Thu, 20 Mar 2014 17:57:41 +0100
Message-ID: <532B1E05.70409@free.fr> (raw)
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
I have a very complex view zinfoexp and running the view as:
SELECT * FROM zinfoexp WHERE idmembre in (1,84)
take 2700 ms
So, I try another syntax:
SELECT * FROM zinfoexp WHERE idmembre = 1
union
SELECT * FROM zinfoexp WHERE idmembre = 84
and for me, two calls to my view takes a lot of time (may be x2) and it
takes 134 ms !
How is it possible that the optimizer cannot optimize the IN as UNION ?
I have a database postgresql 9.3 freshly vacuumed
--
Jean-Max Reymond
CKR Solutions Open Source http://www.ckr-solutions.com
--
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: jmreymond@free.fr
Subject: Re: Performance of UNION vs IN
In-Reply-To: <532B1E05.70409@free.fr>
* 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