Re: Introduce XID age and inactive timeout based replication slot invalidation
vignesh C <vignesh21@gmail.com>
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API reference →
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Add a test for commit ac0e33136a using the injection point.
- 8a695d7998be 18.0 landed
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Invalidate inactive replication slots.
- ac0e33136abc 18.0 landed
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Fix incorrect slot type in BuildTupleHashTableExt
- d96d1d5152f3 18.0 cited
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Allow synced slots to have their inactive_since.
- 6f132ed693b6 17.0 landed
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Change last_inactive_time to inactive_since in pg_replication_slots.
- 6d49c8d4b4f4 17.0 landed
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Track last_inactive_time in pg_replication_slots.
- a11f330b5584 17.0 landed
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Track invalidation_reason in pg_replication_slots.
- 6ae701b4378d 17.0 landed
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Add option force_initdb to PostgreSQL::Test::Cluster:init()
- ff9e1e764fcc 17.0 cited
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Add a failover option to subscriptions.
- 776621a5e479 17.0 cited
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Allow setting failover property in the replication command.
- 73292404370c 17.0 cited
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Allow to enable failover property for replication slots via SQL API.
- c393308b69d2 17.0 cited
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Track conflict_reason in pg_replication_slots.
- 007693f2a3ac 17.0 cited
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Log messages for replication slot acquisition and release.
- 7c3fb505b14e 17.0 cited
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Remove vacuum_defer_cleanup_age
- 1118cd37eb61 16.0 cited
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Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids
- be504a3e974d 16.0 cited
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meson: Add initial version of meson based build system
- e6927270cd18 16.0 cited
On Wed, 4 Dec 2024 at 15:01, Nisha Moond <nisha.moond412@gmail.com> wrote: > > On Tue, Dec 3, 2024 at 1:09 PM Hayato Kuroda (Fujitsu) > <kuroda.hayato@fujitsu.com> wrote: > > > > Dear Nisha, > > > > Thanks for updating the patch! > > > > > Fixed. It is reasonable to align with other timeout parameters by > > > using milliseconds as the unit. > > > > It looks you just replaced to GUC_UNIT_MS, but the documentation and > > postgresql.conf.sample has not been changed yet. They should follow codes. > > Anyway, here are other comments, mostly cosmetic. > > > > Here is v53 patch-set addressing all the comments in [1] and [2]. Currently, replication slots are invalidated based on the replication_slot_inactive_timeout only during a checkpoint. This means that if the checkpoint_timeout is set to a higher value than the replication_slot_inactive_timeout, slot invalidation will occur only when the checkpoint is triggered. Identifying the invalidation slots might be slightly delayed in this case. As an alternative, users can forcefully invalidate inactive slots that have exceeded the replication_slot_inactive_timeout by forcing a checkpoint. I was thinking we could suggest this in the documentation. + <para> + Slot invalidation due to inactive timeout occurs during checkpoint. + The duration of slot inactivity is calculated using the slot's + <link linkend="view-pg-replication-slots">pg_replication_slots</link>.<structfield>inactive_since</structfield> + value. + </para> + We could accurately invalidate the slots using the checkpointer process by calculating the invalidation time based on the active_since timestamp and the replication_slot_inactive_timeout, and then set the checkpointer's main wait-latch accordingly for triggering the next checkpoint. Ideally, a different process handling this task would be better, but there is currently no dedicated daemon capable of identifying and managing slots across streaming replication, logical replication, and other slots used by plugins. Additionally, overloading the checkpointer with this responsibility may not be ideal. As an alternative, we could document about this delay in identifying and mention that it could be triggered by forceful manual checkpoint. Regards, Vignesh