recovery_target_lsn

Definition PG 18 manual

This parameter specifies the LSN of the write-ahead log location up to which recovery will proceed. The precise stopping point is also influenced by recovery_target_inclusive. This parameter is parsed using the system data type pg_lsn.

How it works

Sets the LSN of the write-ahead log location up to which recovery will proceed. The value is fixed when the server starts, so changing it requires a restart.

Recovery replays up to a pg_lsn location, with recovery_target_inclusive selecting the side of the boundary. The LSN must lie on the chosen recovery timeline and be reachable from the base backup's WAL chain.

At most one of recovery_target, recovery_target_lsn, recovery_target_name, recovery_target_time, and recovery_target_xid may be set; timeline, inclusive, and action are modifiers. Rehearse from the same base backup through a complete WAL chain—an unreachable target makes targeted recovery fail.

Operational considerations

Using an LSN from a different cluster or a timeline not descended from the base backup.

Setting another recovery target selector at the same time.

Choosing inclusive without identifying which WAL record must be included.

Requesting an LSN beyond the available archive/streaming WAL and getting an unreachable target.

Comparing LSNs as ordinary decimal numbers instead of pg_lsn values.

Workload guidance

OLAP: For a large restore, budget WAL replay and inspection time first. Validate the reached point read-only; do not let heavy analytical queries delay or contaminate the recovery decision.

OLTP: This is not a steady-state performance knob. Set recovery_target_lsn only on an isolated recovery instance after recording target evidence, base backup, timeline, and expected boundary; rehearse and require a second-person review.

SMALL: Prefer a backup tool that generates a controlled recovery configuration. Never leave target settings in ordinary primary/standby templates, and clean up signal files and targets afterward.