Horton

Re: pg_upgrade and logical replication

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: vignesh C <vignesh21@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Julien Rouhaud <rjuju123@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-11-09T06:18:19Z
Lists: pgsql-hackers 
On Wed, Nov 8, 2023 at 10:52 PM vignesh C <vignesh21@gmail.com> wrote:
>
> Upgrading 2 node circular logical replication cluster:
> 1) Let's say we have a circular logical replication setup Node1->Node2
> & Node2->Node1. Here Node2 is subscribing to Node1 and Node1 is
> subscribing to Node2.
> 2) Stop the server in Node1.
> 3) Disable the subscriptions in Node2.
> 4) Upgrade the node Node1 to Node1_new.
> 5) Start the node Node1_new.
> 6) Enable the subscriptions in Node1_new.
> 7) Wait till all the incremental changes are synchronized.
> 8) Alter the subscription connections in Node2 to point from Node1 to Node1_new.
> 9) Create any tables that were created in Node2 between step-2 and now
> and Refresh the publications.
>

I haven't reviewed all the steps yet but here steps 7 and 9 seem to
require some validation. How can incremental changes be synchronized
till all the new tables are created and synced before step 7?

-- 
With Regards,
Amit Kapila.

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