Horton

Re: POC: enable logical decoding when wal_level = 'replica' without a server restart

shveta malik <shveta.malik@gmail.com>

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From: shveta malik <shveta.malik@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, shveta malik <shveta.malik@gmail.com>
Date: 2025-06-04T10:10:38Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix regression test failure when wal_level is set to minimal.

  2. Toggle logical decoding dynamically based on logical slot presence.

  3. Disallow server start with sync_replication_slots = on and wal_level < logical.

On Wed, Jun 4, 2025 at 6:41 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Tue, May 20, 2025 at 9:54 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > Yeah, I find the idea that the presence of a logical slot will allow
> > the user to enable logical decoding/replication more appealing than
> > this new alternative, leaving aside the challenges of realizing it.

+1. This idea appears more user-friendly and easier to understand
compared to other approaches, such as having multiple GUCs or using
ALTER SYSTEM.

> I've drafted this idea. Here are summary for attached two patches:
>
> 0001 patch allows us to create a logical slot without WAL reservation.
>
> 0002 patch is the main patch for dynamically enabling/disabling
> logical decoding when wal_level is 'replica'.

Thank You for the patches. I have done some initial testing, it seems
to be working well. I will do more testing and review and will share
further feedback.

thanks
Shveta