From: Tom Lane <tgl@sss.pgh.pa.us>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: zotov@oe-it.ru
Cc: pgsql-performance@postgresql.org
Subject: Re: Bad plan when join on function
Date: Mon, 17 Jan 2011 16:33:44 -0500
Message-ID: <21547.1295300024@sss.pgh.pa.us> (raw)
In-Reply-To: <AANLkTi=527XTtWUfgXQKwG8AGENxyKUvJHRxYgSje39W@mail.gmail.com>
References: <4D34576C02000025000396CB@gw.wicourts.gov>
<AANLkTi=527XTtWUfgXQKwG8AGENxyKUvJHRxYgSje39W@mail.gmail.com>
Pavel Stehule <pavel.stehule@gmail.com> writes:
> it should to work without functional index - but not sure about effectivity
As long as the function is VOLATILE, the planner can't use any
intelligent query plan. Merge or hash join both require at least
stable join keys.
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, pavel.stehule@gmail.com, Kevin.Grittner@wicourts.gov, zotov@oe-it.ru
Subject: Re: Bad plan when join on function
In-Reply-To: <21547.1295300024@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