Contents
pg_copy_physical_replication_slot()
A function for duplicating a physical replication slot
pg_copy_physical_replication_slot() is a system function for copying an existing physical replication slot.
pg_copy_physical_replication_slot() was added in PostgreSQL 12.
Usage
pg_copy_physical_replication_slot ( src_slot_name name, dst_slot_name name [, temporary boolean ] ) → record ( slot_name name, lsn pg_lsn )
The slot to be copied must have been created with reserved WAL (i.e. pg_create_physical_replication_slot() executed with immediately_reserve set to TRUE).
Change history
- PostgreSQL 12
- added (commit 9f06d79e)
Examples
Copying a replication slot using pg_copy_physical_replication_slot():
postgres=# SELECT * FROM pg_create_physical_replication_slot('foo', immediately_reserve := TRUE);
slot_name | lsn
-----------+-----------
foo | 0/30004B0
(1 row)
postgres=# SELECT * FROM pg_copy_physical_replication_slot('foo', 'bar');
slot_name | lsn
-----------+-----
bar |
(1 row)
Note that as of PostgreSQL 14, pg_copy_physical_replication_slot() does not return a value in the lsn column, even though one is reported via pg_replication_slots:
postgres=# SELECT slot_name, slot_type, restart_lsn, wal_status FROM pg_replication_slots; slot_name | slot_type | restart_lsn | wal_status -----------+-----------+-------------+------------ foo | physical | 0/30004B0 | reserved bar | physical | 0/30004B0 | reserved (2 rows)
The source replication slot must have been created with reserved WAL:
postgres=# SELECT * FROM pg_create_physical_replication_slot('boo');
slot_name | lsn
-----------+-----
boo |
(1 row)
postgres=# SELECT * FROM pg_copy_physical_replication_slot('boo', 'baz');
ERROR: cannot copy a replication slot that doesn't reserve WAL
Attempting to copy a non-existent replication slot:
postgres=# SELECT * FROM pg_copy_physical_replication_slot('zoo', 'baz');
ERROR: replication slot "zoo" does not exist
References
- PostgreSQL documentation: Replication Management Functions