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From: Amit Kapila <amit.kapila16@gmail.com>
Date: Thu, 13 Oct 2022 09:19:26 +0530
Message-ID: 
 <CAA4eK1+OBVyu5Vy3dCH_ofF7qBprdB9iq-71Pa1kynii_Ly0UQ@mail.gmail.com>
Subject: Re: Perform streaming logical transactions by background workers and
 parallel apply
To: "kuroda.hayato@fujitsu.com" <kuroda.hayato@fujitsu.com>
Cc: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>,
 Dilip Kumar <dilipbalaut@gmail.com>,
	Masahiko Sawada <sawada.mshk@gmail.com>,
 "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>,
	Peter Smith <smithpb2250@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	"wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>
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On Thu, Oct 6, 2022 at 6:09 PM kuroda.hayato@fujitsu.com
<kuroda.hayato@fujitsu.com> wrote:
>
> ~~~
> 10. worker.c - apply_handle_stream_start
>
> ```
> + *
> + * XXX We can avoid sending pair of the START/STOP messages to the parallel
> + * worker because unlike apply worker it will process only one
> + * transaction-at-a-time. However, it is not clear whether that is worth the
> + * effort because it is sent after logical_decoding_work_mem changes.
> ```
>
> I can understand that START message is not needed, but is STOP really removable? If leader does not send STOP to its child, does it lose a chance to change the worker-state to IDLE_IN_TRANSACTION?
>

I think if we want we can set that state before we went to sleep in
parallel apply worker. So, I guess ideally we don't need both of these
messages but for now, it is fine as mentioned in the comments.

-- 
With Regards,
Amit Kapila.