On Wed, Oct 4, 2023 at 12:08 PM Drouvot, Bertrand <bertranddrouvot...@gmail.com> wrote: > > Hi, > > On 10/4/23 7:00 AM, shveta malik wrote: > > On Wed, Oct 4, 2023 at 9:56 AM shveta malik <shveta.ma...@gmail.com> wrote: > > > The most simplistic approach would be: > > > > 1) maintain standby_slot_names GUC on primary > > 2) maintain synchronize_slot_names GUC on physical standby alone. > > > > On primary, let all logical-walsenders wait on physical-standbys > > configured in standby_slot_names GUC. This will work and will avoid > > all the complexity involved in designs discussed above. But this > > simplistic approach comes with disadvantages like below: > > > > 1) Even if the associated slot of logical-walsender is not part of > > synchronize_slot_names of any of the physical-standbys, it is still > > waiting for all the configured standbys to finish. > > That's right. Currently (with walsender waiting an arbitrary amount of time) > that sounds like a -1. But if we're going with a new CV approach (like > proposed > in [1], that might not be so terrible). Though I don't feel comfortable with > waiting for no reasons (even if this is for a short amount of time possible). >
Agreed. Not a good idea to block each logical walsender. > > 2) If associated slot of logical walsender is part of > > synchronize_slot_names of standby1, it is still waiting on standby2,3 > > etc to finish i.e. waiting on rest of the standbys configured in > > standby_slot_names which have not even marked that logical slot in > > their synchronize_slot_names. > > > > Same thoughts as above for 1) > > > So we need to weigh our options here. > > > > With the simplistic approach, if a standby goes down that would impact non > related > walsenders on the primary until the standby's associated physical slot is > removed > from standby_slot_names and I don't feel comfortable wit this behavior. > > So, I'm +1 for the ReplicationSlotPersistentData approach proposed by Amit. yes, +1 for ReplicationSlotPersistentData approach. Will start detailed analysis on that approach now. thanks Shveta