2 files changed, 10 insertions, 2 deletions
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a6c0351c815..d4f294f4aa6 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -261,7 +261,7 @@ WalReceiverMain(void)
 
 	SpinLockRelease(&walrcv->mutex);
 
-	pg_atomic_init_u64(&WalRcv->writtenUpto, 0);
+	pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
 
 	/* Arrange to clean up at walreceiver exit */
 	on_shmem_exit(WalRcvDie, 0);
@@ -1376,7 +1376,6 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
 	state = WalRcv->walRcvState;
 	receive_start_lsn = WalRcv->receiveStart;
 	receive_start_tli = WalRcv->receiveStartTLI;
-	written_lsn = pg_atomic_read_u64(&WalRcv->writtenUpto);
 	flushed_lsn = WalRcv->flushedUpto;
 	received_tli = WalRcv->receivedTLI;
 	last_send_time = WalRcv->lastMsgSendTime;
@@ -1396,6 +1395,14 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
 	if (pid == 0 || !ready_to_display)
 		PG_RETURN_NULL();
 
+	/*
+	 * Read "writtenUpto" without holding a spinlock.  Note that it may not be
+	 * consistent with the other shared variables of the WAL receiver
+	 * protected by a spinlock, but this should not be used for data integrity
+	 * checks.
+	 */
+	written_lsn = pg_atomic_read_u64(&WalRcv->writtenUpto);
+
 	/* determine result type */
 	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
 		elog(ERROR, "return type must be a row type");
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index c3e317df9ff..3984228a113 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -63,6 +63,7 @@ WalRcvShmemInit(void)
 		MemSet(WalRcv, 0, WalRcvShmemSize());
 		WalRcv->walRcvState = WALRCV_STOPPED;
 		SpinLockInit(&WalRcv->mutex);
+		pg_atomic_init_u64(&WalRcv->writtenUpto, 0);
 		WalRcv->latch = NULL;
 	}
 }