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From: Robert Haas <robertmhaas@gmail.com>
Date: Mon, 25 Oct 2021 10:45:21 -0400
Message-ID: 
 <CA+TgmoZrtgZCTA++wOS+=nXGPhrp6965EZorpRfyvyEpFfdWiQ@mail.gmail.com>
Subject: Re: [Patch] ALTER SYSTEM READ ONLY
To: Amul Sul <sulamul@gmail.com>
Cc: Jaime Casanova <jcasanov@systemguards.com.ec>,
 Rushabh Lathia <rushabh.lathia@gmail.com>,
	Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>,
	Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
	Ibrar Ahmed <ibrar.ahmad@gmail.com>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>,
 Prabhat Sahu <prabhat.sahu@enterprisedb.com>
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On Mon, Oct 25, 2021 at 3:05 AM Amul Sul <sulamul@gmail.com> wrote:
> Ok, did the same in the attached 0001 patch.
>
> There is no harm in calling LocalSetXLogInsertAllowed() calling
> multiple times, but the problem I can see is that with this patch user
> is allowed to call LocalSetXLogInsertAllowed() at the time it is
> supposed not to be called e.g. when LocalXLogInsertAllowed = 0;
> WAL writes are explicitly disabled.

I've pushed 0001 and 0002 but I reversed the order of them and made a
few other edits.

I don't really see the issue you mention here as a problem. There's
only one place where we set LocalXLogInsertAllowed = 0, and I don't
know that we'll ever have another one.

-- 
Robert Haas
EDB: http://www.enterprisedb.com