On Wed, Oct 15, 2025 at 9:50 PM Masahiko Sawada <[email protected]> wrote: > > On Wed, Oct 15, 2025 at 3:56 AM Amit Kapila <[email protected]> wrote: > > > > On Tue, Oct 14, 2025 at 11:40 PM Masahiko Sawada <[email protected]> > > wrote: > > > > > > On Tue, Oct 14, 2025 at 2:24 AM shveta malik <[email protected]> > > > wrote: > > > > > > > > Thanks. I was testing slot-sync worker flow and noticed that even if > > > > 'sync_replication_slots' is enabled, it takes quite some time (1-2 > > > > mins) for slot sync worker to start. On noticing > > > > XLOG_LOGICAL_DECODING_STATUS_CHANGE, isn't there a way to (or > > > > shouldn't we) wakeup postmaster to start slotsync worker immediately? > > > > > > > > Logs for timestamps reference: > > > > > > > > 2025-10-14 14:41:32.852 IST [208475] LOG: replication slot > > > > synchronization requires "effective_wal_level" >= "logical" on the > > > > primary > > > > 2025-10-14 14:41:32.852 IST [208475] HINT: To enable logical decoding > > > > on primary, set "wal_level" >= "logical" or create at least one > > > > logical slot when "wal_level" = "replica". > > > > 2025-10-14 14:41:35.499 IST [208481] LOG: update logical decoding > > > > status to 1 > > > > 2025-10-14 14:41:35.499 IST [208481] CONTEXT: WAL redo at 0/03000060 > > > > for XLOG/LOGICAL_DECODING_STATUS_CHANGE: true > > > > 2025-10-14 14:42:53.611 IST [208529] LOG: slot sync worker started > > > > ------ > > > > > > I think that this particular situation happened because the postmaster > > > was sleeping and didn't have any tasks. If a new connection comes in > > > or the existing connection exits, the postmaster launches the slotsync > > > worker. I believe it would not be a serious issue in practice. > > > > > > > Right, but OTOH, do we see any harm if we wake up the postmaster on > > such an event? It shouldn't happen frequently to matter either way > > though. > > It's not harmful in practice. I've considered waking up the postmaster > with a new PMSignalReason, but I thought it's overkill to introduce a > new reason just to wake up the postmaster. If there is a convenient > way, I'd like to use that. >
Do you think we can use PMSIGNAL_BACKGROUND_WORKER_CHANGE for this reason? Otherwise, I see different processes have separate reasons like PMSIGNAL_START_AUTOVAC_LAUNCHER, PMSIGNAL_START_AUTOVAC_WORKER, or PMSIGNAL_START_WALRECEIVER to signal postmaster for similar purpose. -- With Regards, Amit Kapila.
