Horton

How can end users know the cause of LR slot sync delays?

Ashutosh Sharma <ashu.coek88@gmail.com>

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From: Ashutosh Sharma <ashu.coek88@gmail.com>
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-08-28T05:36:42Z
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. Rename column slotsync_skip_at to slotsync_last_skip.

  2. Add slotsync_skip_reason column to pg_replication_slots view.

  3. Fix test failure caused by commit 76b78721ca.

  4. Fix a BF failure caused by commit 76b78721ca.

  5. Add slotsync skip statistics.

Hi,

We have seen cases where slot synchronization gets delayed, for example
when the slot is behind the failover standby or vice versa, and the slot
sync worker has to wait for one to catch up with the other. During this
waiting period, users querying pg_replication_slots can only see whether
the slot has been synchronized or not. If it has already synchronized,
that’s fine, but if synchronization is taking longer, users would naturally
want to understand the reason for the delay.

Is there a way for end users to know the cause of slot synchronization
delays, so they can take appropriate actions to speed it up?

I understand that server logs are emitted in such cases, but logs are not
something end users would want to check regularly. Moreover, since logging
is configuration-based, relevant messages may sometimes be skipped or
suppressed.

Thanks & Regards,
Ashutosh Sharma.