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In-Reply-To: 
 <OS0PR01MB5716965E416547A42DE1E35094009@OS0PR01MB5716.jpnprd01.prod.outlook.com>
From: Amit Kapila <amit.kapila16@gmail.com>
Date: Fri, 11 Nov 2022 12:51:45 +0530
Message-ID: 
 <CAA4eK1LZY_LM_10JDBNx63RCcVGOcvTjf_c66axFimJNhDZa9g@mail.gmail.com>
Subject: Re: Perform streaming logical transactions by background workers and
 parallel apply
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>,
	"wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>,
 Peter Smith <smithpb2250@gmail.com>,
	Dilip Kumar <dilipbalaut@gmail.com>,
 "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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 <https://www.postgresql.org/message-id/CAA4eK1LZY_LM_10JDBNx63RCcVGOcvTjf_c66axFimJNhDZa9g%40mail.gmail.com>
Precedence: bulk

On Fri, Nov 11, 2022 at 7:57 AM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> On Monday, November 7, 2022 6:18 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > Here are comments on v42-0001:
> >
> > We have the following three similar name functions regarding to
> > starting a new parallel apply worker:
> > ---
> >          /*
> >           * Exit if any parameter that affects the remote connection
> > was changed.
> > -         * The launcher will start a new worker.
> > +         * The launcher will start a new worker, but note that the
> > parallel apply
> > +         * worker may or may not restart depending on the value of
> > the streaming
> > +         * option and whether there will be a streaming transaction.
> >
> > In which case does the parallel apply worker don't restart even if the
> > streaming option has been changed?
>
> Sorry, I forgot to reply to this comment. If user change the streaming option from
> 'parallel' to 'on' or 'off', the parallel apply workers won't be restarted.
>

How about something like the below so as to be more explicit about
this in the comments?
diff --git a/src/backend/replication/logical/worker.c
b/src/backend/replication/logical/worker.c
index bfe326bf0c..74cd5565bd 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -3727,9 +3727,10 @@ maybe_reread_subscription(void)

        /*
         * Exit if any parameter that affects the remote connection was changed.
-        * The launcher will start a new worker, but note that the
parallel apply
-        * worker may or may not restart depending on the value of the streaming
-        * option and whether there will be a streaming transaction.
+        * The launcher will start a new worker but note that the parallel apply
+        * worker won't restart if the streaming option's value is changed from
+        * 'parallel' to any other value or the server decides not to stream the
+        * in-progress transaction.
         */

-- 
With Regards,
Amit Kapila.