Message-ID: <457698805e88b7692300586bef905c1f9cac72e1.camel@oopsware.de>
Subject: Re: Offline enabling/disabling of data checksums
From: Bernd Helmle <mailings@oopsware.de>
To: Fabien COELHO <coelho@cri.ensmp.fr>
Cc: Michael Banck <michael.banck@credativ.de>, Magnus Hagander
 <magnus@hagander.net>, Michael Paquier <michael@paquier.xyz>, Postgres
 hackers <pgsql-hackers@postgresql.org>
Date: Tue, 08 Jan 2019 16:41:35 +0100
In-Reply-To: <alpine.DEB.2.21.1901081614210.32421@lancre>
References: <20181221201616.GD4974@nighthawk.caipicrew.dd-dns.de>
	   <alpine.DEB.2.21.1812261900400.32444@lancre>
	   <20181227011534.GD2106@paquier.xyz>
	   <CABUevEwbPVR_6Uv4D44fCd9tB_=aFxG4awUx+DJawD8_speuCA@mail.gmail.com>
	   <alpine.DEB.2.21.1812271206340.32444@lancre>
	 <1546945543.32387.8.camel@credativ.de>
	  <alpine.DEB.2.21.1901081505010.32421@lancre>
	 <65e4f3684f7563acc8b309393b8e14388b5eae0d.camel@oopsware.de>
	 <alpine.DEB.2.21.1901081614210.32421@lancre>
Content-Type: text/plain; charset="UTF-8"
User-Agent: Evolution 3.30.3 (3.30.3-1.fc29) 
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Precedence: bulk

Am Dienstag, den 08.01.2019, 16:17 +0100 schrieb Fabien COELHO:
> > > Adding a new state to ControlFileData which would prevent it from
> > > starting?
> > 
> > But then you have to make sure the control flag gets cleared in any
> > case pg_verify_checksums crashes somehow or gets SIGKILL'ed ...
> 
> The usual approach is a restart with some --force option?
> 
> > Setting the checksum flag is done after having finished all blocks,
> > so
> > there is no problem.
> 
> There is also a problem if the db is started while the checksum is
> being 
> enabled.

What i mean is that interrupting pg_verify_checksums won't leave
pg_control in a state where starting the cluster won't work without any
further interaction.

Bernd.