Patch for pg_upgrade to turn off autovacuum

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Alvaro Herrera <alvherre(at)commandprompt(dot)com>, Jeff Davis <pgsql(at)j-davis(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Patch for pg_upgrade to turn off autovacuum
Date: 2011-04-21 20:47:35
Message-ID: 201104212047.p3LKlZh26387@momjian.us
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Bruce Momjian wrote:
> Robert Haas wrote:
> > On Thu, Mar 31, 2011 at 12:11 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> > > Robert Haas wrote:
> > >> On Thu, Mar 31, 2011 at 11:32 AM, Heikki Linnakangas
> > >> <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> > >> >> ?I think the maintenance
> > >> >> overhead of an invisible variable is too much.
> > >> >
> > >> > A simple GUC or command-line switch isn't much code.
> > >>
> > >> I like the idea of a command-line switch.
> > >
> > > If you want to do that you should gereralize it as --binary-upgrade in
> > > case we have other needs for it.
> >
> > Yeah. Or we could do a binary_upgrade GUC which has the effect of
> > forcibly suppressing autovacuum, and maybe other things later. I
> > think that's a lot less hazardous than fiddling with the autovacuum
> > GUC.
>
> I like the idea of a command-line flag because it forces everything to
> be affected, and cannot be turned on and off in sessions --- if you are
> doing a binary upgrade, locked-down is good. :-)

The attached patch adds a new postmaster/postgres binary upgrade mode
(-b) which disables autovacuum, allows only super-user connections, and
prevents pg_upgrade_support oid assignment when not in upgrade mode.
It also modifies pg_upgrade to use this new mode rather than play with
trying to stop autovacuum.

This does fix a very rare bug that could happen if
autovacuum_freeze_max_age were set to maximum by the user.

I think this should be applied to PG 9.1.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

Attachment Content-Type Size
/rtmp/pg_upgrade text/x-diff 15.3 KB

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