Hi, On Tue, Jun 24, 2025 at 12:13:32AM +0900, Masahiko Sawada wrote: > On Mon, Jun 23, 2025 at 7:01 PM Bertrand Drouvot > <bertranddrouvot...@gmail.com> wrote: > > > > Hi, > > > > On Mon, Jun 23, 2025 at 05:10:37PM +0900, Masahiko Sawada wrote: > > > On Thu, Jun 19, 2025 at 6:00 PM Bertrand Drouvot > > > <bertranddrouvot...@gmail.com> wrote: > > > > > > > > - pg_activate_logical_decoding() is needed only if there is not already > > > > a logical > > > > slot on the primary > > > > - the drop requires the user to think twice if this is the last logical > > > > slot > > > > - we don't ask the user to create a logical slot if he does not want to > > > > use it > > > > on the primary > > > > > > > > Thoughts? > > > > > > If there is no logical slot on the primary, how can the user disable > > > logical decoding that has been enabled via > > > pg_activate_logical_decoding()? > > > > I was thinking to keep the pg_deactivate_logical_decoding() API proposed > > in this thread. > > Okay. One approach that combines your idea and Shveta's idea is: > > - a special (empty) logical slot with the reserved slot name can be > created and deleted only by SQL functions, > pg_activate_logical_decoding() and pg_deactivate_logical_decoding(). > - this special slot cannot be used by logical decoding. > - effective_wal_level is increased and decreased when creating and > dropping a slot (i.e., either a normal logical slots or the special > logical slot).
Yeah, I think that sounds reasonable and that would avoid users to use the slot created with immediately_reserve set to false by mistake. > > You mean a GUC to both automaticly set effective_wal_level to logical at > > slot creation > > and also decrease effective_wal_level to replica if last replication slot > > is dropped? > > What I imagined was to control only the decreasing behavior that could > be more problematic than the increase case. But it might be rather > confusing (e.g., what if we turn off that behavior and restart the > server?). Right...So not sure we need such a GUC. What about always behave with the automatic behavior? Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
