From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Kellerer <spam_eater@gmx.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: Using ctid column changes plan drastically
Date: Tue, 24 Jul 2012 10:23:01 -0400
Message-ID: <21308.1343139781@sss.pgh.pa.us> (raw)
In-Reply-To: <julsfr$otg$1@dough.gmane.org>
References: <julsfr$otg$1@dough.gmane.org>
Thomas Kellerer <spam_eater@gmx.net> writes:
> DELETE FROM dupes
> WHERE id NOT IN (SELECT min(b.id)
> FROM dupes b
> GROUP BY first_name, last_Name
> HAVING count(*) > 1);
Doesn't that kill the non-duplicates too?
> Why does the usage of the CTID column change the plan so drastically?
IIRC, type tid doesn't have any hash support.
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, spam_eater@gmx.net
Subject: Re: Using ctid column changes plan drastically
In-Reply-To: <21308.1343139781@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