From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Thomas Munro <thomas.munro@enterprisedb.com>,
        Andres Freund <andres@anarazel.de>, amul sul <sul_amul@yahoo.co.in>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Server crash due to SIGBUS(Bus Error) when trying to access the
 memory created using dsm_create().
In-reply-to: 
 <CA+TgmoY+pXip_OrQdii91iH0UJpL6Z6NTqQ3ETwBj_Chg8jNrg@mail.gmail.com>
References: <25838.1471010881@sss.pgh.pa.us>
 <CAEepm=24jFz-Bm6awX-U=qfvcxrbQVS1ZU6uUry07r=aGyePgg@mail.gmail.com>
 <CAEepm=1ySPpiPG8hyy98vTGbvi6uXvavsy-zahevkM=tTRUDSQ@mail.gmail.com>
 <CA+TgmoagA8KGfUZzQs8xMTt2rqjw1Ko+vJQV05R=qZz2a98OGQ@mail.gmail.com>
 <CAEepm=0euOKPaYWz0-gFv9xfG+8ptAjhFjiQEX0CCJaYN--sDQ@mail.gmail.com>
 <CA+TgmoYw296PTpQ+iFqcqWECR5x9QW-TE+Rd5Lv9=p0XCxZvOA@mail.gmail.com>
 <CAEepm=27q=VLg5Mh76a1NfzK=9Xi1jnrpYm5VQNbQQJomwhU4A@mail.gmail.com>
 <CA+TgmoY=jMECqMz=RKG3=x=kvMZrf008Ggc4mYNyajqbVkMW4w@mail.gmail.com>
 <CAEepm=3KjgWXAqseQOXxpz4DtkZJ9U5Zcx9hU8iFrVtm5mwFKg@mail.gmail.com>
 <CAEepm=2GAgjcnLGCHOCVTD04eVR+rP+8_-6Z4c391-AFo1sL7g@mail.gmail.com>
 <20170628230458.n5ehizmvhoerr5yq@alap3.anarazel.de>
 <CAEepm=00bvrcNGaHWv7=9F_SE9YKfW1_DuFbAjFh41ycg8mLxw@mail.gmail.com>
 <CAEepm=37ptJz+epr6+iW+O1wCCAxeT04r27Uc8rXmJBoFT2ExA@mail.gmail.com>
 <CAEepm=3b+Wu81XgseDcc_a6JUC6_JCgyj41LGWfY1qto3gE1KA@mail.gmail.com>
 <26247.1506349378@sss.pgh.pa.us> <CA+TgmoY+pXip_OrQdii91iH0UJpL6!
 Z6NTqQ3ETwBj_Chg8jNrg@mail.gmail.com>
Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Mon, 25 Sep 2017 12:13:27 -0400"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <487.1506364109.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Mon, 25 Sep 2017 14:28:29 -0400
Message-ID: <488.1506364109@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Sep 25, 2017 at 10:22 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I think we don't really have a lot of choice.  I propose applying this
>> as far back as 9.6 --- anyone think differently?

> +1.  If applies to 9.5 and 9.4 without a lot of work, I think we
> should apply it there as well, in case there is out-of-core use of DSM
> (or, in 9.5, also of ParallelContext).

Hmm, so I tested this patch on my RHEL6 box (kernel 2.6.32) and it
immediately fell over with

2017-09-25 14:23:48.410 EDT [325] FATAL:  could not resize shared memory se=
gment "/PostgreSQL.1682054886" to 6928 bytes: Operation not supported

during startup.  I wonder whether we need to round off the request.

			regards, tom lane


--=20
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers