Re: Track in pg_replication_slots the reason why slots conflict?

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Michael Paquier <michael@paquier.xyz>

Cc: Postgres hackers <pgsql-hackers@lists.postgresql.org>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Andres Freund <andres@anarazel.de>

Date: 2023-12-21T02:50:16Z

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 →

Track conflict_reason in pg_replication_slots.
- 007693f2a3ac 17.0 landed

On Thu, Dec 21, 2023 at 5:51 AM Michael Paquier <michael@paquier.xyz> wrote:
>
> While listening at Bertrand's talk about logical decoding on standbys
> last week at Prague, I got surprised by the fact that we do not
> reflect in the catalogs the reason why a conflict happened for a slot.
> There are three of them depending on ReplicationSlotInvalidationCause:
> - WAL removed.
> - Invalid horizon.
> - Insufficient WAL level.
>

The invalidation cause is also required by one of the features being
discussed "Synchronize slots from primary to standby" [1] and there is
already a thread to discuss the same [2]. As that thread started
yesterday only, you may not have noticed it. Currently, the proposal
is to expose it via a function but we can extend it to also display
via view, feel free to share your opinion on that thread.

[1] - https://www.postgresql.org/message-id/514f6f2f-6833-4539-39f1-96cd1e011f23@enterprisedb.com
[2] - https://www.postgresql.org/message-id/CAJpy0uBpr0ym12%2B0mXpjcRFA6N%3DanX%2BYk9aGU4EJhHNu%3DfWykQ%40mail.gmail.com

-- 
With Regards,
Amit Kapila.