Horton

Re: Decoding of two-phase xacts missing from CREATE_REPLICATION_SLOT command

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Ajin Cherian <itsajin@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Amit Kapila <akapila@postgresql.org>, vignesh C <vignesh21@gmail.com>, Peter Smith <smithpb2250@gmail.com>
Date: 2021-06-09T22:43:14Z
Lists: pgsql-hackers 
On Wed, 2021-06-09 at 17:27 +0530, Amit Kapila wrote:
> 2. In the main patch [1], we do send two_phase option even during
> START_REPLICATION for the very first time when the two_phase can be
> enabled. There are reasons as described in the worker.c why we can't
> enable it during CREATE_REPLICATION_SLOT. 

I'll have to catch up on the thread to digest that reasoning and how it
applies to decoding vs. replication. But there don't seem to be changes
to START_REPLICATION for twophase, so I don't quite follow your point.

Are you saying that we should not be able to create slots with twophase
at all until the rest of the changes go in?

> Now, if we want to do
> protocol changes, I wonder why only do some changes and leave the
> rest
> for the next version?

I started this thread because it's possible to create a slot a certain
way using the SQL function create_logical_replication_slot(), but it's
impossible over the replication protocol. That seems inconsistent to
me.

Regards,
	Jeff Davis

Commits

  1. Remove two_phase variable from CreateReplicationSlotCmd struct.

  2. Add option to enable two_phase commits via pg_create_logical_replication_slot.