Horton

Re: [HACKERS] make async slave to wait for lsn to be replayed

Alexander Korotkov <aekorotkov@gmail.com>

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From: Alexander Korotkov <aekorotkov@gmail.com>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: Kartyshov Ivan <i.kartyshov@postgrespro.ru>, pgsql-hackers@lists.postgresql.org
Date: 2024-03-26T23:49:17Z
Lists: pgsql-hackers 
On Fri, Mar 22, 2024 at 12:50 AM Peter Eisentraut <peter@eisentraut.org> wrote:
> On 19.03.24 18:38, Kartyshov Ivan wrote:
> >               CALL pg_wait_lsn('0/3002AE8', 10000);
> >               BEGIN;
> >               SELECT * FROM tbl; // read fresh insertions
> >               COMMIT;
>
> I'm not endorsing this or any other approach, but I think the timeout
> parameter should be of type interval, not an integer with a unit that is
> hidden in the documentation.

I'm not sure a timeout needs to deal with complexity of our interval
datatype.  At the same time, the integer number of milliseconds looks
a bit weird.  Could the float8 number of seconds be an option?

------
Regards,
Alexander Korotkov

Commits

  1. Ensure standby promotion point in 043_wal_replay_wait.pl

  2. Minor cleanup related to pg_wal_replay_wait() procedure

  3. Adjust pg_wal_replay_wait() procedure behavior on promoted standby

  4. pg_wal_replay_wait(): Fix typo in the doc

  5. Implement pg_wal_replay_wait() stored procedure

  6. Revert: Implement pg_wal_replay_wait() stored procedure

  7. Call WaitLSNCleanup() in AbortTransaction()

  8. Clarify what is protected by WaitLSNLock

  9. Use an LWLock instead of a spinlock in waitlsn.c

  10. Use the pairing heap instead of a flat array for LSN replay waiters

  11. Minor improvements for waitlsn.c

  12. Make the order of the header file includes consistent