Horton

Re: pg_upgrade and logical replication

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: vignesh C <vignesh21@gmail.com>
Cc: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Julien Rouhaud <rjuju123@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Amit Kapila <amit.kapila16@gmail.com>
Date: 2023-09-19T06:19:29Z
Lists: pgsql-hackers 
On Fri, Sep 15, 2023 at 04:51:57PM +0530, vignesh C wrote:
> Another approach to solve this as suggested by one of my colleague
> Hou-san would be to set max_logical_replication_workers = 0 while
> upgrading. I will evaluate this and update the next version of patch
> accordingly.

In the context of an upgrade, any node started is isolated with its
own port and a custom unix domain directory with connections allowed
only through this one.

Saying that, I don't see why forcing max_logical_replication_workers
to be 0 would be necessarily a bad thing to prevent unnecessary
activity on the backend.  This should be a separate patch built on
top of the main one, IMO.

Looking forward to seeing the rebased version you've mentioned, btw ;)
--
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