Yes Shveta! I could see repeated message in New-replica .
2025-06-13 06:20:30.146 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:20:30.146 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:21:00.176 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:21:00.176 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:21:30.207 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:21:30.207 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:22:00.238 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:22:00.238 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:22:30.268 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:22:30.268 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:23:00.299 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:23:00.299 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:23:30.329 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:23:30.329 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:24:00.360 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:24:00.360 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:24:30.391 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:24:30.391 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:25:00.421 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:25:00.421 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. 2025-06-13 06:25:30.452 UTC [277861] LOG: could not synchronize replication slot "kafka_logical_slot" because remote slot precedes local slot 2025-06-13 06:25:30.452 UTC [277861] DETAIL: The remote slot has LSN 0/6D0000B8 and catalog xmin 1085, but the local slot has LSN 0/6F000000 and catalog xmin 1088. It appears that my Debezium connectors have stopped consuming data, resulting in an outdated restart_lsn of "0/6D0000B8". In contrast, the New_replica has a restart_lsn that matches the primary server's most recent confirmed_flush_lsn, indicating it is up to date. *As soon as I recreate that replication slot, it got sync with New_Replica(temporary=false) .* 2025-06-13 06:26:00.484 UTC [277861] LOG: dropped replication slot "kafka_logical_slot" of database with OID 16384 2025-06-13 06:26:30.520 UTC [277861] LOG: starting logical decoding for slot "kafka_logical_slot" 2025-06-13 06:26:30.520 UTC [277861] DETAIL: Streaming transactions committing after 0/0, reading WAL from 0/76003140. 2025-06-13 06:26:30.520 UTC [277861] LOG: logical decoding found consistent point at 0/76003140 2025-06-13 06:26:30.520 UTC [277861] DETAIL: There are no running transactions. 2025-06-13 06:26:30.526 UTC [277861] LOG: newly created replication slot "kafka_logical_slot" is sync-ready now 2025-06-13 06:35:39.212 UTC [277857] LOG: restartpoint starting: time 2025-06-13 06:35:42.022 UTC [277857] LOG: restartpoint complete: wrote 29 buffers (0.2%); 0 WAL file(s) added, 0 removed, 0 recycled; write=2.805 s, sync=0.002 s, total=2.810 s; sync files=26, longest=0.002 s, average=0.001 s; distance=16496 kB, estimate=16496 kB; lsn=0/7701F480, redo lsn=0/7701F428 2025-06-13 06:35:42.022 UTC [277857] LOG: recovery restart point at 0/7701F428 2025-06-13 06:35:42.022 UTC [277857] DETAIL: Last completed transaction was at log time 2025-06-13 06:33:31.675341+00. *Until the synchronization is complete, the slot type is marked as temporary=true, as you mentioned.* is there any manual way to advance *"**restart_lsn"* of logical replication slot ? This is to ensure slot synchronization. Thanks, On Thu, Jun 12, 2025 at 8:49 PM shveta malik <shveta.ma...@gmail.com> wrote: > On Fri, Jun 13, 2025 at 6:23 AM Perumal Raj <peruci...@gmail.com> wrote: > > > > Hi Hou zj > > > > I have found some strange issue , but not sure if I am doing anything > wrong. > > > > I am able to see logical slot at STANDBY even after promote. 👏 > > Good to know. > > > > > Importantly Logical replication slot is persistance in STANDBYs which > already established connection with Primary before logical replication slot > creation. > > > > But If I create any new replica(Direct to Primary) after logical > replication slot creation, then its not persistance(temporary=true) . > > > > > > New Replica : > > node | slot_name | slot_type | temporary | active | > plugin | database | failover | synced | restart_lsn | > confirmed_flush_lsn | inactive_since > > > ----------+--------------------+-----------+-----------+--------+----------+---------------+----------+--------+-------------+---------------------+------------------------------ > > stand-by | kafka_logical_slot | logical | t | t | > pgoutput | replica_test | t | t | 0/6C000000 | > | 2025-06-13 00:43:15.61492+00 > > > > Old Replica , > > node | slot_name | slot_type | temporary | active | > plugin | database | failover | synced | restart_lsn | > confirmed_flush_lsn | inactive_since > > > ----------+--------------------+-----------+-----------+--------+----------+---------------+----------+--------+-------------+---------------------+------------------------------- > > stand-by | kafka_logical_slot | logical | f | f | > pgoutput | replica_test | t | t | 0/6D000060 | 0/6D000098 > | 2025-06-13 00:45:11.547671+00 > > > > > > Not sure if any Pre-Req missing in my test environment. Or any > limitation . > > It may be a possibility that the slot is not sync-ready yet (and thus > not persisted) on new-replica due to primary having older values of > xmin and lsn. We do not allow persisting a synced slot if the > required WAL or catalog rows for this slot have been removed or are at > risk of removal on standby. The slot will be persisted in the next > few cycles of automatic slot-synchronization when it is ensured that > source slot's values are safe to be synced to the standby. But to > confirm my diagnosis, please provide this information: > > 1) > Output of this query on both primary and new-replica (where slot is > temporary) > select slot_name, failover, synced, temporary, catalog_xmin, > restart_lsn, confirmed_flush_lsn from pg_replication_slots; > > 2) > Please check logs on new-replica to see the presence of log: > LOG: could not synchronize replication slot "kafka_logical_slot". > > If found, please provide us with both the LOG and DETAIL messages > dumped in the log file. > > thanks > Shveta >
