On Tue, Mar 19, 2024 at 6:12 PM Bertrand Drouvot <bertranddrouvot...@gmail.com> wrote: > > On Tue, Mar 19, 2024 at 04:20:35PM +0530, Amit Kapila wrote: > > On Tue, Mar 19, 2024 at 3:11 PM Bertrand Drouvot > > <bertranddrouvot...@gmail.com> wrote: > > > > > > On Tue, Mar 19, 2024 at 10:56:25AM +0530, Amit Kapila wrote: > > > > On Mon, Mar 18, 2024 at 8:19 PM Bertrand Drouvot > > > > <bertranddrouvot...@gmail.com> wrote: > > > > > Agree. While it makes sense to invalidate slots for wal removal in > > > > > CreateCheckPoint() (because this is the place where wal is removed), > > > > > I 'm not > > > > > sure this is the right place for the 2 new cases. > > > > > > > > > > Let's focus on the timeout one as proposed above (as probably the > > > > > simplest one): > > > > > as this one is purely related to time and activity what about to > > > > > invalidate them > > > > > when?: > > > > > > > > > > - their usage resume > > > > > - in pg_get_replication_slots() > > > > > > > > > > The idea is to invalidate the slot when one resumes activity on it or > > > > > wants to > > > > > get information about it (and among other things wants to know if the > > > > > slot is > > > > > valid or not). > > > > > > > > > > > > > Trying to invalidate at those two places makes sense to me but we > > > > still need to cover the cases where it takes very long to resume the > > > > slot activity and the dangling slot cases where the activity is never > > > > resumed. > > > > > > I understand it's better to have the slot reflecting its real status > > > internally > > > but it is a real issue if that's not the case until the activity on it is > > > resumed? > > > (just asking, not saying we should not) > > > > > > > Sorry, I didn't understand your point. Can you try to explain by example? > > Sorry if that was not clear, let me try to rephrase it first: what issue to > you > see if the invalidation of such a slot occurs only when its usage resume or > when pg_get_replication_slots() is triggered? I understand that this could > lead > to the slot not being invalidated (maybe forever) but is that an issue for an > inactive slot? >
It has the risk of preventing WAL and row removal. I think this is the primary reason we are at the first place planning to have such a parameter. So, we should have some way to invalidate it even when the walsender/backend process doesn't use it again. -- With Regards, Amit Kapila.
