From 7234376b2d6fa6b86cc9e4ed95a52af7bd6225e6 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horiguchi.kyotaro@lab.ntt.co.jp>
Date: Fri, 18 Nov 2016 12:44:25 +0900
Subject: [PATCH 1/2] Slows replication processing.

To cause sync-rep desync artificially, sleep 100ms for each
replication message if /tmp/slow exists.
---
 src/backend/replication/walreceiver.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 2bb3dce..57f3ad2 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -439,6 +439,11 @@ WalReceiverMain(void)
 							 */
 							last_recv_timestamp = GetCurrentTimestamp();
 							ping_sent = false;
+							{
+								struct stat b;
+								if (stat("/tmp/slow", &b) >= 0)
+									usleep(100000);
+							}
 							XLogWalRcvProcessMsg(buf[0], &buf[1], len - 1);
 						}
 						else if (len == 0)
-- 
2.9.2