From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jonatan Evald Buus <jonatan.buus@cellpointmobile.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Poor performance for delete query
Date: Thu, 24 Apr 2014 17:25:03 -0400
Message-ID: <29874.1398374703@sss.pgh.pa.us> (raw)
In-Reply-To: <CABnF-8J9G7XfEuyV-DhUb3VkuZ_XCF=t7_okJFW7nZ1qMmi94Q@mail.gmail.com>
References: <CABnF-8Lyps8ribpp=BOFnqGEeWp2K5iuLukMo3txQ5UkgHjF7g@mail.gmail.com>
<28604.1398371340@sss.pgh.pa.us>
<CABnF-8J9G7XfEuyV-DhUb3VkuZ_XCF=t7_okJFW7nZ1qMmi94Q@mail.gmail.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
Jonatan Evald Buus <jonatan.buus@cellpointmobile.com> writes:
> On 24 April 2014 22:29, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I'd really have to bet that you forgot to index one of the referencing
>> tables.
> *That was our first thought, so we went through the child tables to check
> but apparently we missed some. (please see below for the difference in the
> explain analyze output)*
I'm confused. Your second EXPLAIN ANALYZE looks like you fixed the
problem. Are you still thinking there's an issue?
> Why is "order2transaction_fk" being triggered twice? Is that because
> there're two affected rows?
No, I'd have expected a delete of multiple rows to show as calls=N,
not N separate entries.
Maybe there are recursive queries buried under here somewhere?
That is, are you expecting any of the cascaded deletes to cascade further?
I don't recall exactly what EXPLAIN is likely to do with such cases.
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, jonatan.buus@cellpointmobile.com
Subject: Re: Poor performance for delete query
In-Reply-To: <29874.1398374703@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