Hi, On Fri, Mar 22, 2024 at 02:59:21PM +0530, Amit Kapila wrote: > On Fri, Mar 22, 2024 at 2:27 PM Bertrand Drouvot > <bertranddrouvot...@gmail.com> wrote: > > > > On Fri, Mar 22, 2024 at 01:45:01PM +0530, Bharath Rupireddy wrote: > > > > > 0001 Track invalidation_reason in pg_replication_slots > > > 0002 Track last_inactive_at in pg_replication_slots > > > 0003 Allow setting inactive_timeout for replication slots via SQL API > > > 0004 Introduce new SQL funtion pg_alter_replication_slot > > > 0005 Allow setting inactive_timeout in the replication command > > > 0006 Add inactive_timeout based replication slot invalidation > > > > > > 1. Keep it last_inactive_at as a shared memory variable, but always > > > set it at restart if the slot's inactive_timeout has non-zero value > > > and reset it as soon as someone acquires that slot so that if the slot > > > doesn't get acquired till inactive_timeout, checkpointer will > > > invalidate the slot. > > > 4. last_inactive_at should also be set to the current time during slot > > > creation because if one creates a slot and does nothing with it then > > > it's the time it starts to be inactive. > > > > I did not look at the code yet but just tested the behavior. It works as you > > describe it but I think this behavior is weird because: > > > > - when we create a slot without a timeout then last_inactive_at is set. I > > think > > that's fine, but then: > > - when we restart the engine, then last_inactive_at is gone (as timeout is > > not > > set). > > > > I think last_inactive_at should be set also at engine restart even if there > > is > > no timeout. > > I think it is the opposite. Why do we need to set 'last_inactive_at' > when inactive_timeout is not set?
I think those are unrelated, one could want to know when a slot has been inactive even if no timeout is set. I understand that for this patch series we have in mind to use them both to invalidate slots but I think that there is use case to not use both in correlation. Also not setting last_inactive_at could give the "false" impression that the slot is active. > BTW, haven't we discussed that we > don't need to set 'last_inactive_at' at the time of slot creation as > it is sufficient to set it at the time ReplicationSlotRelease()? Right. Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
