Re: Fix stats reporting delays in logical parallel apply worker

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2026-04-17T07:19:36Z
Lists: pgsql-hackers
On Fri, Apr 17, 2026 at 8:31 AM Zhijie Hou (Fujitsu)
<houzj.fnst@fujitsu.com> wrote:
>
> When implementing another feature, I noticed that parallel apply workers
> currently do not report statistics while idle in their main loop. This can cause
> stats from the last processed transaction to be arbitrarily delayed, especially
> when there are long gaps between streamed transactions.
>
> The issue is demonstrated in 0002, where a TAP test fails when attempting to
> collect stats from a parallel apply worker that has no subsequent transaction to
> trigger a stats report.
>
> 0001 fixes this issue by forcing a stats report when the worker is idle in the
> main loop, matching the behavior already present in LogicalRepApplyLoop() for
> regular logical apply workers.
>

LGTM. We should backpatch this change.

-- 
With Regards,
Amit Kapila.



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  1. Flush statistics during idle periods in parallel apply worker.