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Re: Logical replication launcher did not automatically restart when got SIGKILL

Fujii Masao <masao.fujii@gmail.com>

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From: Fujii Masao <masao.fujii@gmail.com>
To: shveta malik <shveta.malik@gmail.com>
Cc: cca5507 <cca5507@qq.com>, Fujii Masao <masao.fujii@oss.nttdata.com>, pgsql-hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-07-25T01:47:18Z
Lists: pgsql-hackers

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On Thu, Jul 24, 2025 at 6:46 PM shveta malik <shveta.malik@gmail.com> wrote:
> Sounds reasonable.
> Thinking out loud, when cleaning up after a backend or background
> worker crash, process_pm_child_exit() is invoked, which subsequently
> calls both CleanupBackend() and HandleChildCrash(). After the cleanup
> completes, process_pm_child_exit() calls PostmasterStateMachine() to
> move to the next state. As part of that, PostmasterStateMachine()
> invokes ResetBackgroundWorkerCrashTimes() (only in crash
> scenarios/FatalError), to reset a few things. Since it also resets
> rw_worker.bgw_notify_pid, it seems reasonable to reset the rw_pid as
> well there.

Thanks!
Attached is a patch that fixes the issue by resetting rw_pid in
ResetBackgroundWorkerCrashTimes().

We should probably add a regression test for this case,
but I'd prefer to commit the fix first and work on the test separately.
Andrey Rudometov proposed a test patch in thread [1],
which we might use as a starting point.

Regards,

[1] https://postgr.es/m/CAF6JsWiO=i24qYitWe6ns1sXqcL86rYxdyU+pNYk-WueKPSySg@mail.gmail.com

-- 
Fujii Masao

Commits

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

  1. Add regression test for background worker restart after crash.

  2. Fix background worker not restarting after crash-and-restart cycle.

  3. Refactor code to handle death of a backend or bgworker in postmaster