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base repository: postgresql-cfbot/postgresql
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  • 3 commits
  • 17 files changed
  • 2 contributors

Commits on Feb 18, 2025

  1. Introduce inactive_timeout based replication slot invalidation 

    Tools that create replication slots (e.g., for migrations or upgrades) may
fail to remove them if an error occurs, leaving behind unused slots that
take up space and resources. Manually cleaning them up can be tedious and
error-prone, and without intervention, these lingering slots can cause
unnecessary WAL retention and system bloat.

Till now, postgres has the ability to invalidate inactive replication slots
based on the amount of WAL (set via max_slot_wal_keep_size GUC) that will
be needed for the slots in case they become active. However, setting an
optimal value for this is tricky since the amount of WAL a database
generates, and the allocated storage per instance will vary greatly in
production. A high value may allow orphaned slots to persist longer than
necessary, leading to system bloat by retaining WAL unnecessarily.

This commit introduces idle_replication_slot_timeout, a simpler and more
intuitive way to manage inactive slots. Instead of relying on WAL size,
users can set a time limit (e.g., 1 or 2 or n days), after which slots that
remain idle for longer than this amount of time are automatically
invalidated during checkpoints.

Note that the idle timeout invalidation mechanism is not applicable
for slots that do not reserve WAL or for slots on the standby server
that are being synced from the primary server (i.e., standby slots
having 'synced' field 'true'). Synced slots are always considered to be
inactive because they don't perform logical decoding to produce changes.
    @nishamoond
    nishamoond authored and Commitfest Bot committed Feb 18, 2025
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  2. Add TAP test for slot invalidation based on inactive timeout. 

    This test uses injection points to bypass the time overhead caused by the
idle_replication_slot_timeout GUC, which has a minimum value of one minute.
    @nishamoond
    nishamoond authored and Commitfest Bot committed Feb 18, 2025
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  3. [CF 52/4770] v79 - Introduce XID age and inactive timeout based repli… 

    …cation slot invalidation

This commit was automatically generated by a robot at cfbot.cputube.org.
It is based on patches submitted to the PostgreSQL mailing lists and
registered in the PostgreSQL Commitfest application.

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

Commitfest entry: https://commitfest.postgresql.org/52/4770
Patch(es): https://www.postgresql.org/message-id/CABdArM7v0N0Kz1x0HjnuJZgDC8e=ZGgfCgSywsm4imgmpWghDA@mail.gmail.com
Author(s):
    Commitfest Bot committed Feb 18, 2025
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