From e06a560466e53b3a8a8e2b2fa232635ef962b1db Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Mon, 27 May 2013 10:45:37 +0200
Subject: [PATCH] Send ACK to master once every second.

ACKs can be also used as a base for synchronous replication. However in
that case they'll be explicitly requested by the master when the client
sends a request that needs to be replicated synchronously.
---
 src/replication.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/replication.c b/src/replication.c
index a326ee8a..2791f3b9 100644
--- a/src/replication.c
+++ b/src/replication.c
@@ -1441,6 +1441,10 @@ void replicationCron(void) {
             redisLog(REDIS_NOTICE,"MASTER <-> SLAVE sync started");
         }
     }
+
+    /* Send ACK to master from time to time. */
+    if (server.masterhost && server.master)
+        replicationSendAck();
     
     /* If we have attached slaves, PING them from time to time.
      * So slaves can implement an explicit timeout to masters, and will