WAITLSN
WAITLSN — wait for the target LSN to be replayed
Synopsis
WAITLSN'LSN'[ ,wait_time]
Description
WAITLSN provides a simple interprocess communication mechanism to wait for the target log sequence number (LSN) on standby in Postgres Pro databases with master-standby asynchronous replication. When run with the LSN option, the WAITLSN command waits for the specified LSN to be replayed. By default, wait time is unlimited. Waiting can be interrupted using Ctrl+C, or by shutting down the postgres server. You can also limit the wait time specifying the wait_time option, in milliseconds.
Important
The WAITLSN command is deprecated.
Parameters
LSNSpecify the target log sequence number to wait for.
wait_timeLimit the time to wait for the LSN to be replayed. The specified
wait_timemust be an integer and is measured in milliseconds.
Examples
Run WAITLSN from psql, limiting wait time to 10000 milliseconds:
WAITLSN '0/3F07A6B1', 10000; NOTICE: LSN is not reached. Try to make bigger delay. WAITLSN
Wait until the specified LSN is replayed:
WAITLSN '0/3F07A611'; WAITLSN ------------- t (1 row)
Limit LSN wait time to 500000 milliseconds, and then cancel the command:
WAITLSN '0/3F0FF791', 500000; ^CCancel request sent NOTICE: LSN is not reached. Try to make bigger delay. ERROR: canceling statement due to user request
Compatibility
There is no WAITLSN statement in the SQL standard.