1 files changed, 12 insertions, 14 deletions
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 2217af70d43..c35ea7c35bf 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -502,6 +502,14 @@ retry:
 
 	/* We made this slot active, so it's ours now. */
 	MyReplicationSlot = s;
+
+	/*
+	 * The call to pgstat_acquire_replslot() protects against stats for
+	 * a different slot, from before a restart or such, being present during
+	 * pgstat_report_replslot().
+	 */
+	if (SlotIsLogical(s))
+		pgstat_acquire_replslot(s);
 }
 
 /*
@@ -746,20 +754,10 @@ ReplicationSlotDropPtr(ReplicationSlot *slot)
 	elog(DEBUG3, "replication slot drop: %s: removed directory", NameStr(slot->data.name));
 
 	/*
-	 * Send a message to drop the replication slot to the stats collector.
-	 * Since there is no guarantee of the order of message transfer on a UDP
-	 * connection, it's possible that a message for creating a new slot
-	 * reaches before a message for removing the old slot. We send the drop
-	 * and create messages while holding ReplicationSlotAllocationLock to
-	 * reduce that possibility. If the messages reached in reverse, we would
-	 * lose one statistics update message. But the next update message will
-	 * create the statistics for the replication slot.
-	 *
-	 * XXX In case, the messages for creation and drop slot of the same name
-	 * get lost and create happens before (auto)vacuum cleans up the dead
-	 * slot, the stats will be accumulated into the old slot. One can imagine
-	 * having OIDs for each slot to avoid the accumulation of stats but that
-	 * doesn't seem worth doing as in practice this won't happen frequently.
+	 * Drop the statistics entry for the replication slot.  Do this while
+	 * holding ReplicationSlotAllocationLock so that we don't drop a
+	 * statistics entry for another slot with the same name just created in
+	 * another session.
 	 */
 	if (SlotIsLogical(slot))
 		pgstat_drop_replslot(slot);