diff --git a/collector/pg_replication.go b/collector/pg_replication.go
index 790f85329..6067cc9b1 100644
--- a/collector/pg_replication.go
+++ b/collector/pg_replication.go
@@ -55,6 +55,7 @@ var (
 	pgReplicationQuery = `SELECT
 	CASE
 		WHEN NOT pg_is_in_recovery() THEN 0
+                WHEN pg_last_wal_receive_lsn () = pg_last_wal_replay_lsn () THEN 0
 		ELSE GREATEST (0, EXTRACT(EPOCH FROM (now() - pg_last_xact_replay_timestamp())))
 	END AS lag,
 	CASE