diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a39a98f..8f5fe4d 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -33,7 +33,7 @@
  * specific parts are in the libpqwalreceiver module. It's loaded
  * dynamically to avoid linking the server with libpq.
  *
- * Portions Copyright (c) 2010-2018, PostgreSQL Global Development Group
+ * Portions Copyright (c) 2010-2017, PostgreSQL Global Development Group
  *
  *
  * IDENTIFICATION
@@ -944,6 +944,12 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr)
 {
 	int			startoff;
 	int			byteswritten;
+	static char *zbuffer = NULL;
+	static int	lastfile = -1;
+	static int	lastblock = -1;
+
+	if (zbuffer == NULL)
+		zbuffer = palloc0(XLOG_BLCKSZ);
 
 	while (nbytes > 0)
 	{
@@ -1040,6 +1046,36 @@ XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr)
 
 		LogstreamResult.Write = recptr;
 	}
+
+	/*
+	 * Zero-fill the remaining portion of the last block so that the XLOG reader won't get confused with the garbage left over from a recycled WAL segment.
+	 * Remember the last zero-filled block to avoid filling the same block repeatedly.
+	 */
+	if (recvOff % XLOG_BLCKSZ != 0 &&
+		!(recvFile == lastfile && recvOff / XLOG_BLCKSZ == lastblock))
+	{
+		int			bytestowrite;
+
+		bytestowrite = XLOG_BLCKSZ - recvOff % XLOG_BLCKSZ;
+		errno = 0;
+		byteswritten = write(recvFile, zbuffer, bytestowrite);
+		if (byteswritten != bytestowrite)
+		{
+			/* if write didn't set errno, assume no disk space */
+			if (errno == 0)
+				errno = ENOSPC;
+			ereport(PANIC,
+					(errcode_for_file_access(),
+					 errmsg("could not write to log segment %s "
+							"at offset %u, length %lu: %m",
+							XLogFileNameP(recvFileTLI, recvSegNo),
+							recvOff, (unsigned long) bytestowrite)));
+		}
+
+		lastfile = recvFile;
+		lastblock = recvOff / XLOG_BLCKSZ;
+		recvOff += byteswritten;
+	}
 }
 
 /*
@@ -1442,8 +1478,7 @@ pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
 	if (!is_member_of_role(GetUserId(), DEFAULT_ROLE_READ_ALL_STATS))
 	{
 		/*
-		 * Only superusers and members of pg_read_all_stats can see details.
-		 * Other users only get the pid value
+		 * Only superusers can see details. Other users only get the pid value
 		 * to know whether it is a WAL receiver, but no details.
 		 */
 		MemSet(&nulls[1], true, sizeof(bool) * (tupdesc->natts - 1));