Horton

Re: Introduce XID age and inactive timeout based replication slot invalidation

shveta malik <shveta.malik@gmail.com>

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From: shveta malik <shveta.malik@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, shveta malik <shveta.malik@gmail.com>
Date: 2024-03-13T07:15:06Z
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. Add a test for commit ac0e33136a using the injection point.

  2. Invalidate inactive replication slots.

  3. Fix incorrect slot type in BuildTupleHashTableExt

  4. Allow synced slots to have their inactive_since.

  5. Change last_inactive_time to inactive_since in pg_replication_slots.

  6. Track last_inactive_time in pg_replication_slots.

  7. Track invalidation_reason in pg_replication_slots.

  8. Add option force_initdb to PostgreSQL::Test::Cluster:init()

  9. Add a failover option to subscriptions.

  10. Allow setting failover property in the replication command.

  11. Allow to enable failover property for replication slots via SQL API.

  12. Track conflict_reason in pg_replication_slots.

  13. Log messages for replication slot acquisition and release.

  14. Remove vacuum_defer_cleanup_age

  15. Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids

  16. meson: Add initial version of meson based build system

> JFYI, the patch does not apply to the head. There is a conflict in
> multiple files.

For review purposes, I applied v8 to the March 6 code-base. I have yet
to review in detail, please find my initial thoughts:

1)
I found that 'inactive_replication_slot_timeout' works only if there
was any walsender ever started for that slot . The logic is under
'am_walsender' check.  Is this intentional?
If I create a slot and use only pg_logical_slot_get_changes or
pg_replication_slot_advance on it, it never gets invalidated due to
timeout.  While, when I set 'max_slot_xid_age' or say
'max_slot_wal_keep_size' to a lower value, the said slot is
invalidated correctly with 'xid_aged' and 'wal_removed' reasons
respectively.

Example:
With inactive_replication_slot_timeout=1min, test1_3  is the slot for
which there is no walsender and only advance and get_changes SQL
functions were called; test1_4 is the one for which pg_recvlogical was
run for a second.

 test1_3     |   785 | | reserved   |                           | t
    |                                  |
 test1_4     |   798 | | lost       | inactive_timeout    | t        |
2024-03-13 11:52:41.58446+05:30  |

And when inactive_replication_slot_timeout=0  and max_slot_xid_age=10

 test1_3     |   785 | | lost       |          xid_aged       | t
  |                                  |
 test1_4     |   798 | | lost       | inactive_timeout    | t        |
2024-03-13 11:52:41.58446+05:30  |


2)
The msg for patch 3 says:
--------------
a) when replication slots is lying inactive for a day or so using
last_inactive_at metric,
b) when a replication slot is becoming inactive too frequently using
last_inactive_at metric.
--------------
 I think in b, you want to refer to inactive_count instead of last_inactive_at?

3)
I do not see invalidation_reason updated for 2 new reasons in system-views.sgml


thanks
Shveta