Hi, Andrey! On Thu, Nov 27, 2025 at 12:19 PM Andrey Silitskiy <[email protected]> wrote: > On Nov 23, 2025 at 11:46 PM Fujii Masao > <masao(dot)fujii(at)gmail(dot)com> wrote: > > The difference is that PGC_USERSET also allows per–replication-user > > overrides when needed, which gives users more flexibility without > > losing the ability to set a server-wide setting, I think. > > ... > > I think there are valid use cases for applying this setting to > > physical replication as well. > Thanks for the comments. I agree, this parameter also seems usable > for physical replication, if you use it with caution. In this case, > it really becomes useful to be able to configure a parameter for > each connection. I have added these changes to my patch. > > Also, earlier I did not mention another difference between my patch > and those discussed earlier. Previously, even in immediate mode, > WalSndCaughtUp flag was checked before calling WalSndDone, > and this made it impossible to shut down even in immediate mode > with WalSndCaughtUp = false when the server has full output buffers. > This does not happen in the current patch implementation. I added > an additional test case for this situation.
Thank you for reviving this thread. I think it is reasonable to move control over the walsender shutdown behavior to the primary server. I see an analogy with synchronous_commit and synchronous_standby_names. Primary decides which standbys wait and which way to wait for them. Similarly, the primary should decide who to wait on the shutdown. I would like to make a couple of suggestions for the patch. 1) I think it's useful to tune particular standbys/subscribers to specify the walsender shutdown mode. It was possible in the patch by Hayato Kuroda, and it would be a pity to lose. I suggest implementing the walsender shutdown mode as a replication slot option. 2) Given that walsender shutdown mode would be a replication slot option, I propose to rename GUC to default_wal_sender_shutdown_mode. Also, given we would more likely need to wait for a flush during streaming replication, I would suggest following modes: immediate, wait_for_flush_streaming_only, wait_for_flush. The new intermediate option would make walsender wait for a flush only for physical standbys but not for logical subscribers. What do you think? ------ Regards, Alexander Korotkov Supabase
