Re: [HACKERS] logical decoding of two-phase transactions

On Thu, May 13, 2021 at 7:50 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
>
> Please find attached the latest patch set v75*
>
> Differences from v74* are:
>
> * Rebased to HEAD @ today.
>
> * v75 also addresses some of the feedback comments from Vignesh [1].

Adding a patch to this patch-set that avoids empty transactions from
being sent to the subscriber/replica. This patch is based on the
logic that was proposed for empty transactions in the thread [1]. This
patch uses that patch and handles empty prepared transactions
as well. So, this will avoid empty prepared transactions from being
sent to the subscriber/replica. This patch also avoids sending
COMMIT PREPARED /ROLLBACK PREPARED if the prepared transaction was
skipped provided the COMMIT /ROLLBACK happens
prior to a restart of the walsender. If the COMMIT/ROLLBACK PREPARED
happens after a restart, it will not be able know that the
prepared transaction prior to the restart was not sent, in this case
the apply worker of the subscription will check if a prepare of the
same type exists
and if it does not, it will silently ignore the COMMIT PREPARED
(ROLLBACK PREPARED logic was already doing this).
Do have a look and let me know if you have any comments.

[1] - https://www.postgresql.org/message-id/CAFPTHDYegcoS3xjGBj0XHfcdZr6Y35%2BYG1jq79TBD1VCkK7v3A%40mail.gmail.com

regards,
Ajin Cherian
Fujitsu Australia.