From a91bdf67c49ade2bdf6474607b64f9f0083db4a6 Mon Sep 17 00:00:00 2001
From: Magnus Hagander <magnus@hagander.net>
Date: Sun, 13 Dec 2015 16:53:38 +0100
Subject: [PATCH] Consistently set all fields in pg_stat_replication to null
 instead of 0

Previously the "sent" field would be set to 0 and all other xlog
pointers be set to NULL if there were no valid values (such as when
in a backup sending walsender).
---
 src/backend/replication/walsender.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index c13567298c..7b1b7f1492 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -2822,6 +2822,9 @@ pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
 		else
 		{
 			values[1] = CStringGetTextDatum(WalSndGetStateString(state));
+
+			if (XLogRecPtrIsInvalid(sentPtr))
+				nulls[2] = true;
 			values[2] = LSNGetDatum(sentPtr);
 
 			if (XLogRecPtrIsInvalid(write))