From: Tom Lane <tgl@sss.pgh.pa.us>
To: Adam Brusselback <adambrusselback@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Query much slower after upgrade to 9.6.1
Date: Mon, 07 Nov 2016 14:16:49 -0500
Message-ID: <3809.1478546209@sss.pgh.pa.us> (raw)
In-Reply-To: <CAMjNa7cWH=rHs7x96wGfNd5DxzTtLyO-ZxZmia8MXaO+eQ1EzA@mail.gmail.com>
References: <CAMjNa7cirhpZxx-9HaDcXNFt95w7eoXLwWscTBa2kEFzLQFaZg@mail.gmail.com>
<CAMjNa7cWH=rHs7x96wGfNd5DxzTtLyO-ZxZmia8MXaO+eQ1EzA@mail.gmail.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
Adam Brusselback <adambrusselback@gmail.com> writes:
> As suggested in the Postgres slack channel by lukasfittl, I disabled
> hashagg on my old server, and ran the query again. That changed one piece
> to a groupagg (like was used on the new server) and the performance was
> similar to the 9.6.1 box.
If the problem is "new server won't use hashagg", I'd wonder whether
the work_mem setting is the same, or whether maybe you need to bump
it up some (the planner's estimate of how big the hashtable would be
might have changed a bit).
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, adambrusselback@gmail.com
Subject: Re: Query much slower after upgrade to 9.6.1
In-Reply-To: <3809.1478546209@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