Horton

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

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: shveta malik <shveta.malik@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, Shlok Kyal <shlok.kyal.oss@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2025-10-22T09:28:38Z
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, Oct 22, 2025 at 2:40 PM shveta malik <shveta.malik@gmail.com> wrote:
>
> On Fri, Oct 17, 2025 at 11:09 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
>
> I want to discuss the create-publication case, which currently gives
> this warning:
>
> postgres=# create publication pub1 for all tables;
> WARNING:  logical decoding should be allowed to publish logical changes
> HINT:  Before creating subscriptions, set "wal_level" >= "logical" or
> create a logical replication slot when "wal_level" = "replica".
> CREATE PUBLICATION
>
> But is this warning really necessary during publication creation?
>

On HEAD, the WARNING/HINT is as follows for the above case:
WARNING:  "wal_level" is insufficient to publish logical changes
HINT:  Set "wal_level" to "logical" before creating subscriptions.

Shouldn't we simply change the HINT to "Set "wal_level" to "logical"
or create a logical replication slot before creating subscriptions."?

-- 
With Regards,
Amit Kapila.