Horton

Re: pg_upgrade and logical replication

Michael Paquier <michael@paquier.xyz>

View thread View on postgr.es
From: Michael Paquier <michael@paquier.xyz>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Julien Rouhaud <rjuju123@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-09-29T00:33:59Z
Lists: pgsql-hackers 
On Wed, Sep 27, 2023 at 07:31:41PM +0530, Amit Kapila wrote:
> On Wed, Sep 27, 2023 at 3:37 PM vignesh C <vignesh21@gmail.com> wrote:
>> Once the table is in SUBREL_STATE_SYNCDONE state, the apply worker
>> will check if the apply worker has some LSN records that need to be
>> applied to reach the LSN of the table. Once the required WAL is
>> applied, the table state will be changed from SUBREL_STATE_SYNCDONE to
>> SUBREL_STATE_READY state. Since there is a chance that in this case
>> the apply worker has to apply some transactions to get all the tables
>> in READY state, I felt the minimum requirement should be that at least
>> all the tables should be in READY state for the upgradation of the
>> Subscriber.
> 
> I don't think this theory is completely correct because the pending
> WAL can be applied even after an upgrade.

Yeah, agreed that putting a pre-check about the state of the relations
stored in pg_subscription_rel when handling the upgrade of a
subscriber is not necessary.
--
Michael

Commits

  1. pg_upgrade: Retrieve subscription count more efficiently.

  2. Fix random failure in 004_subscription.

  3. Fix 004_subscription.pl to allow its usage in --link mode.

  4. Allow upgrades to preserve the full subscription's state.

  5. Prevent startup of logical replication launcher during pg_upgrade