Received: from malur.postgresql.org ([217.196.149.56])
	by arkaria.postgresql.org with esmtp (Exim 4.84_2)
	(envelope-from <pgsql-bugs-owner+archive@lists.postgresql.org>)
	id 1eNEm5-0001TA-1V
	for pgsql-bugs@arkaria.postgresql.org; Fri, 08 Dec 2017 09:16:53 +0000
Received: from localhost ([127.0.0.1] helo=malur.postgresql.org)
	by malur.postgresql.org with esmtp (Exim 4.84_2)
	(envelope-from <pgsql-bugs-owner+archive@lists.postgresql.org>)
	id 1eNEm4-0007FJ-Ev
	for pgsql-bugs@arkaria.postgresql.org; Fri, 08 Dec 2017 09:16:52 +0000
Received: from makus.postgresql.org ([2001:4800:1501:1::229])
	by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256)
	(Exim 4.84_2)
	(envelope-from <mailings@oopsware.de>)
	id 1eNEiS-0008N1-4h
	for pgsql-bugs@lists.postgresql.org; Fri, 08 Dec 2017 09:13:08 +0000
Received: from dd6214.kasserver.com ([85.13.131.7])
	by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256)
	(Exim 4.89)
	(envelope-from <mailings@oopsware.de>)
	id 1eNEiN-0004TS-Sp
	for pgsql-bugs@postgresql.org; Fri, 08 Dec 2017 09:13:06 +0000
Received: from niheb.land.credativ.lan (fw-front.credativ.com [62.154.226.94])
	by dd6214.kasserver.com (Postfix) with ESMTPSA id 7CE461BC062D;
	Fri,  8 Dec 2017 10:13:00 +0100 (CET)
Message-ID: <1512724380.9720.37.camel@oopsware.de>
Subject: Re: PostgreSQL crashes with SIGSEGV
From: Bernd Helmle <mailings@oopsware.de>
To: Peter Geoghegan <pg@bowt.ie>
Cc: pgsql-bugs@postgresql.org
Date: Fri, 08 Dec 2017 10:13:00 +0100
In-Reply-To: 
 <CAH2-WzkYZy633TUDQ6Uc-vq9uUj-57vFFKmZ5jGCskw47mJfLA@mail.gmail.com>
References: <1512661638.9720.34.camel@oopsware.de>
	 <CAH2-WzkYZy633TUDQ6Uc-vq9uUj-57vFFKmZ5jGCskw47mJfLA@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
X-Mailer: Evolution 3.24.6 (3.24.6-1.fc26) 
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
List-Id: <pgsql-bugs.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-bugs@lists.postgresql.org>
List-Owner: <mailto:pgsql-bugs-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-bugs>
Precedence: bulk

Am Donnerstag, den 07.12.2017, 18:23 -0800 schrieb Peter Geoghegan:
> Does "set replacement_sort_tuples = 0" change anything on
> REL9_6_STABLE? If you only get a crash when there is very little
> work_mem, then that might be a good avenue of investigation. Note
> that
> my changes to external sorting started in REL9_6_STABLE, so they
> can't
> be involved here.
> 

replacement_sort_tuples = 0 changes the picture, indeed. With that
setting, the query runs without problems in REL9_6_STABLE.

> Are you aware of commit 512f67c8d02cc558f9c269cc848b0f0f788c4fe1,
> which fixed a bug affecting external sorts? Are you sure that you
> have
> that fix on REL9_5_STABLE + REL9_6_STABLE?

My test instances are build against a fresh pull from yesterday.