Horton

Re: wake up logical workers after ALTER SUBSCRIPTION

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Melih Mutlu <m.melihmutlu@gmail.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2022-12-07T18:11:45Z
Lists: pgsql-hackers

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On Wed, Dec 07, 2022 at 02:07:11PM +0300, Melih Mutlu wrote:
> Do we also need to wake up all sync workers too? Even if not, I'm not
> actually sure whether doing that would harm anything though.
> Just asking since currently the patch wakes up all workers including sync
> workers if any still exists.

After sleeping on this, I think we can do better.  IIUC we can simply check
for AllTablesyncsReady() at the end of process_syncing_tables_for_apply()
and wake up the logical replication workers (which should just consiѕt of
setting the current process's latch) if we are ready for two_phase mode.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Commits

  1. Avoid type cheats for invalid dsa_handles and dshash_table_handles.

  2. Track logrep apply workers' last start times to avoid useless waits.

  3. Check for two_phase change at end of process_syncing_tables_for_apply.

  4. Wake up a subscription's replication worker processes after DDL.