spock.wait_slot_confirm_lsn()

NAME

spock.wait_slot_confirm_lsn()

SYNOPSIS

spock.wait_slot_confirm_lsn (slotname name, target pg_lsn)

RETURNS

void (returns nothing upon successful completion).

DESCRIPTION

Waits until the specified replication slot has confirmed receipt of changes up to the target Log Sequence Number (LSN).

This function blocks the current session until the replication slot's confirmed flush LSN reaches or exceeds the specified target LSN. This is useful for ensuring that a subscriber has received and acknowledged replication changes before proceeding with subsequent operations.

The confirmed flush LSN represents the position up to which the subscriber has successfully received, applied, and durably stored the replicated changes. This function provides a synchronization mechanism to coordinate activities between the provider and subscriber nodes.

If the replication slot does not exist, the function will raise an error. The function will continue waiting indefinitely until the target LSN is reached, so callers should ensure the target LSN is reachable and that the subscription is actively processing changes.

This function does not modify any data but may block for an extended period depending on replication lag and network conditions.

ARGUMENTS

slotname

The name of the replication slot to monitor.

target

The target Log Sequence Number to wait for. The function returns
when the slot's confirmed flush LSN reaches or exceeds this
value.

EXAMPLE

The following command waits for a slot named spock_local_sync_346_79a to confirm that it has received changes to the target LSN (0/3000000):

SELECT spock.wait_slot_confirm_lsn('spock_local_sync_346_79a',
'0/3000000');