Horton

Re: Implement waiting for wal lsn replay: reloaded

Álvaro Herrera <alvherre@kurilemu.de>

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From: Álvaro Herrera <alvherre@kurilemu.de>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Tomas Vondra <tomas@vondra.me>, Yura Sokolov <y.sokolov@postgrespro.ru>, pgsql-hackers@lists.postgresql.org
Date: 2025-08-05T13:47:07Z
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. Clean up 019_replslot_limit.pl comments

  2. Stabilize 019_replslot_limit.pl: wait on slot restart_lsn

  3. Use WAIT FOR LSN in PostgreSQL::Test::Cluster::wait_for_catchup()

  4. Add tab completion for the WAIT FOR LSN MODE option

  5. Add the MODE option to the WAIT FOR LSN command

  6. Extend xlogwait infrastructure with write and flush wait types

  7. Unify error messages

  8. Optimize shared memory usage for WaitLSNProcInfo

  9. Fix WaitLSNWakeup() fast-path check for InvalidXLogRecPtr

  10. Fix incorrect function name in comments

  11. Add infrastructure for efficient LSN waiting

  12. Add pairingheap_initialize() for shared memory usage

  13. Implement WAIT FOR command

Attachments

On 2025-Apr-29, Alexander Korotkov wrote:

> > 11) WaitLSNProcInfo / WaitLSNState
> >
> > Does this need to be exposed in xlogwait.h? These structs seem private
> > to xlogwait.c, so maybe declare it there?
> 
> Hmm, I don't remember why I moved them to xlogwait.h.  OK, moved them
> back to xlogwait.c.

This change made the code no longer compile, because
WaitLSNState->minWaitedLSN is used in xlogrecovery.c which no longer has
access to the field definition.  A rebased version with that change
reverted is attached.

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
Thou shalt study thy libraries and strive not to reinvent them without
cause, that thy code may be short and readable and thy days pleasant
and productive. (7th Commandment for C Programmers)