From 5c6d9fc4b2b8b6688a482a4b4116d7642e36b9d9 Mon Sep 17 00:00:00 2001
From: Fujii Masao <fujii@postgresql.org>
Date: Mon, 17 Mar 2014 20:37:50 +0900
Subject: [PATCH] Fix bug in clean shutdown of walsender that pg_receiving is
 connecting to.

On clean shutdown, walsender waits for all WAL to be replicated to a standby,
and exits. It determined whether that replication had been completed by
checking whether its sent location had been equal to a standby's flush
location. Unfortunately this condition never becomes true when the standby
such as pg_receivexlog which always returns an invalid flush location is
connecting to walsender, and then walsender waits forever.

This commit changes walsender so that it just checks a standby's write
location if a flush location is invalid.

Back-patch to 9.1 where enough infrastructure for this exists.
---
 src/backend/replication/walsender.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 09854112062..6e22c03bcfa 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -2446,10 +2446,20 @@ XLogSendLogical(void)
 static void
 WalSndDone(WalSndSendDataCallback send_data)
 {
+	XLogRecPtr	replicatedPtr;
+
 	/* ... let's just be real sure we're caught up ... */
 	send_data();
 
-	if (WalSndCaughtUp && sentPtr == MyWalSnd->flush &&
+	/*
+	 * Check a write location to see whether all the WAL have
+	 * successfully been replicated if this walsender is connecting
+	 * to a standby such as pg_receivexlog which always returns
+	 * an invalid flush location. Otherwise, check a flush location.
+	 */
+	replicatedPtr = XLogRecPtrIsInvalid(MyWalSnd->flush) ?
+		MyWalSnd->write : MyWalSnd->flush;
+	if (WalSndCaughtUp && sentPtr == replicatedPtr &&
 		!pq_is_send_pending())
 	{
 		/* Inform the standby that XLOG streaming is done */
-- 
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