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base repository: postgresql-cfbot/postgresql
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head repository: postgresql-cfbot/postgresql
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compare: cf/6265
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  • 5 commits
  • 14 files changed
  • 2 contributors

Commits on Dec 11, 2025

  1. Extend xlogwait infrastructure with write and flush wait types 

    Add support for waiting on WAL write and flush LSNs in addition to the
existing replay LSN wait type. This provides the foundation for
extending the WAIT FOR command with MODE parameter.

Key changes:
- Add WAIT_LSN_TYPE_WRITE and WAIT_LSN_TYPE_FLUSH_STANDBY to WaitLSNType
- Add GetCurrentLSNForWaitType() to retrieve current LSN
- Add new wait events WAIT_EVENT_WAIT_FOR_WAL_WRITE and
  WAIT_EVENT_WAIT_FOR_WAL_FLUSH for pg_stat_activity visibility
- Update WaitForLSN() to use GetCurrentLSNForWaitType() internally
    @alterego655
    alterego655 authored and Commitfest Bot committed Dec 11, 2025
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  2. Add MODE parameter to WAIT FOR LSN command 

    Extend the WAIT FOR LSN command with an optional MODE parameter that
specifies which LSN type to wait for:

  WAIT FOR LSN '<lsn>' [MODE { REPLAY | WRITE | FLUSH }] [WITH (...)]

- REPLAY (default): Wait for WAL to be replayed to the specified LSN
- WRITE: Wait for WAL to be written (received) to the specified LSN
- FLUSH: Wait for WAL to be flushed to disk at the specified LSN

The default mode is REPLAY, matching the original behavior when MODE
is not specified. This follows the pattern used by LOCK command where
the mode parameter is optional with a sensible default.

The WRITE and FLUSH modes are useful for scenarios where applications
need to ensure WAL has been received or persisted on the standby
without necessarily waiting for replay to complete.

Also includes:
- Documentation updates for the new syntax and refactoring
  of existing WAIT FOR command documentation
- Test coverage for all three modes including mixed concurrent waiters
- Wakeup logic in walreceiver for WRITE/FLUSH waiters
    @alterego655
    alterego655 authored and Commitfest Bot committed Dec 11, 2025
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  3. Add tab completion for WAIT FOR LSN MODE parameter 

    Update psql tab completion to support the optional MODE parameter in
WAIT FOR LSN command. After specifying an LSN value, completion now
offers both MODE and WITH keywords since MODE defaults to REPLAY.
    @alterego655
    alterego655 authored and Commitfest Bot committed Dec 11, 2025
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  4. Use WAIT FOR LSN in PostgreSQL::Test::Cluster::wait_for_catchup() 

    Replace polling-based catchup waiting with WAIT FOR LSN command when
running on a standby server. This is more efficient than repeatedly
querying pg_stat_replication as the WAIT FOR command uses the latch-
based wakeup mechanism.

The optimization applies when:
- The node is in recovery (standby server)
- The mode is 'replay', 'write', or 'flush' (not 'sent')

For 'sent' mode or when running on a primary, the function falls back
to the original polling approach since WAIT FOR LSN is only available
during recovery.
    @alterego655
    alterego655 authored and Commitfest Bot committed Dec 11, 2025
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  5. [CF 6265] v4 - Add MODE parameter to WAIT FOR LSN command 

    This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/6265

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/CABPTF7U2cYN=bMZirqj93Zv-aqBdw4f=wPRwovTzWKP=adYhDg@mail.gmail.com
Author(s): Xuneng Zhou
    Commitfest Bot committed Dec 11, 2025
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