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. > > There was a lot of discussion regarding slotsync worker in the past, > > please let me know if it is concluded and I missed it somehow. > > Since we've discussed that it's out of scope of this patch that we > shutdown dynamically upon logical decoding status changes, even if > logical decoding status gets disabled on the standby, the slotsync > worker keeps working. If it gets enabled again, we don't need to wake > up the postmaster as the slotsync worker would already be running. I > think we can introduce more dynamic control over the slotsync worker > in a separate patch if we need. > I think it is better to stop the slotsync worker at this event because without a patch we won't even allow the server to restart if the wal_level on standby is less than logical. But, I agree it could be done as a separate patch as well. -- With Regards, Amit Kapila.
