diff --git a/doc/src/sgml/watchdog.sgml b/doc/src/sgml/watchdog.sgml
index 2e5ba046..d71baa4e 100644
--- a/doc/src/sgml/watchdog.sgml
+++ b/doc/src/sgml/watchdog.sgml
@@ -580,6 +580,59 @@
     </listitem>
    </varlistentry>
 
+   <varlistentry id="guc-allow-a-half-consensus" xreflabel="allow_a_half_consensus">
+    <term><varname>allow_a_half_consensus</varname> (<type>boolean</type>)
+     <indexterm>
+      <primary><varname>allow_a_half_consensus</varname> configuration parameter</primary>
+     </indexterm>
+    </term>
+    <listitem>
+     <para>
+      This parameter works in connection with the <xref
+      linkend="guc-failover-require-consensus"> with even number of
+      <productname>Pgpool-II</productname> nodes. Odd number of nodes
+      will not be affected. When enabled, the quorum exists if more
+      than or equal to a half of <productname>Pgpool-II</productname>
+      nodes are alive. If the parameter is off, more than half of
+      nodes need to be alive to make quorum exist.
+     </para>
+     <para>
+      For example, when this parameter is enabled in a two node watchdog
+      cluster, one <productname>Pgpool-II</productname> node needs to
+      be alive to make the quorum exist. If the parameter is off, two
+      nodes need to be alive to make quorum exist.
+     </para>
+     <para>
+      When this parameter is enabled in a four node watchdog cluster,
+      two <productname>Pgpool-II</productname> node needs to be alive
+      to make the quorum exist. If the parameter is off, three nodes
+      need to be alive to make quorum exist.
+     </para>
+     <para>
+      By enabling this parameter, you should aware that you take a
+      risk to make split-brain happen. For example, in four node
+      cluster consisted of node A, B, C and D, it is possible that the
+      cluster goes into two separated networks (A, B) and (C, D). For
+      (A, B) and (C, D) the quorum still exist since for both groups
+      there are two live nodes out of 4. The two groups choose their
+      own master watchdog, which is a split-brain.
+     </para>
+     <para>
+      Default is off.
+     </para>
+     <para>
+      <varname>allow_a_half_consensus</varname> is not available
+      prior to <productname>Pgpool-II
+      </productname><emphasis>V4.1</emphasis>. The prior versions work
+      as if the parameter is on. It is only effective when <xref
+      linkend="guc-failover-require-consensus"> is enabled
+     </para>
+     <para>
+      This parameter can only be set at server start.
+     </para>
+    </listitem>
+   </varlistentry>
+
   </variablelist>
  </sect2>
 
diff --git a/src/config/pool_config_variables.c b/src/config/pool_config_variables.c
index f291f40e..5cc8e420 100644
--- a/src/config/pool_config_variables.c
+++ b/src/config/pool_config_variables.c
@@ -308,6 +308,15 @@ static struct config_bool ConfigureNamesBool[] =
 		false,
 		NULL, NULL, NULL
 	},
+	{
+		{"allow_a_half_consensus", CFGCXT_INIT, FAILOVER_CONFIG,
+			"Quorum exists if more than or equal to a half of even number nodes are alive.",
+			CONFIG_VAR_TYPE_BOOL, false, 0
+		},
+		&g_pool_config.allow_a_half_consensus,
+		false,
+		NULL, NULL, NULL
+	},
 	{
 		{"log_connections", CFGCXT_RELOAD, LOGING_CONFIG,
 			"Logs each successful connection.",
diff --git a/src/include/pool_config.h b/src/include/pool_config.h
index dab3fa3e..178308e4 100644
--- a/src/include/pool_config.h
+++ b/src/include/pool_config.h
@@ -478,6 +478,10 @@ typedef struct
 															 * can send multiple
 															 * failover requests to
 															 * build consensus */
+	bool		allow_a_half_consensus;		/* Quorum exists if more than a
+											 * half of even number nodes are
+											 * alive */
+
 	WdLifeCheckMethod wd_lifecheck_method;	/* method of lifecheck.
 											 * 'heartbeat' or 'query' */
 	bool		clear_memqcache_on_escalation;	/* Clear query cache on shmem
diff --git a/src/include/pool_config_variables.h b/src/include/pool_config_variables.h
index 7bf4f51b..e3841112 100644
--- a/src/include/pool_config_variables.h
+++ b/src/include/pool_config_variables.h
@@ -4,7 +4,7 @@
  * pgpool: a language independent connection pool server for PostgreSQL
  * written by Tatsuo Ishii
  *
- * Copyright (c) 2003-2018	PgPool Global Development Group
+ * Copyright (c) 2003-2019	PgPool Global Development Group
  *
  * Permission to use, copy, modify, and distribute this software and
  * its documentation for any purpose and without fee is hereby
diff --git a/src/sample/pgpool.conf.sample b/src/sample/pgpool.conf.sample
index 4d69fe51..7f79ad15 100644
--- a/src/sample/pgpool.conf.sample
+++ b/src/sample/pgpool.conf.sample
@@ -646,6 +646,9 @@ allow_multiple_failover_requests_from_node = off
                                     # for building the consensus on failover
                                     # (change requires restart)
 
+allow_a_half_consensus = off
+                                    # Quorum exists if more than or equal to a half of even number nodes are alive.
+                                    # (change requires restart)
 # - Lifecheck Setting -
 
 # -- common --
diff --git a/src/sample/pgpool.conf.sample-logical b/src/sample/pgpool.conf.sample-logical
index 6f8cdc7c..a8d3fc35 100644
--- a/src/sample/pgpool.conf.sample-logical
+++ b/src/sample/pgpool.conf.sample-logical
@@ -626,6 +626,9 @@ enable_multiple_failover_requests_from_node = off
                                     # A Pgpool-II node can cast multiple votes
                                     # for building the consensus on failover
 
+allow_a_half_consensus = off
+                                    # Quorum exists if more than or equal to a half of even number nodes are alive.
+                                    # (change requires restart)
 # - Lifecheck Setting -
 
 # -- common --
diff --git a/src/sample/pgpool.conf.sample-master-slave b/src/sample/pgpool.conf.sample-master-slave
index 49bb9664..2e9cda05 100644
--- a/src/sample/pgpool.conf.sample-master-slave
+++ b/src/sample/pgpool.conf.sample-master-slave
@@ -642,6 +642,9 @@ allow_multiple_failover_requests_from_node = off
                                     # (change requires restart)
 
 
+allow_a_half_consensus = off
+                                    # Quorum exists if more than or equal to a half of even number nodes are alive.
+                                    # (change requires restart)
 # - Lifecheck Setting -
 
 # -- common --
diff --git a/src/sample/pgpool.conf.sample-replication b/src/sample/pgpool.conf.sample-replication
index b16322a7..6c9f8f66 100644
--- a/src/sample/pgpool.conf.sample-replication
+++ b/src/sample/pgpool.conf.sample-replication
@@ -642,6 +642,9 @@ allow_multiple_failover_requests_from_node = off
                                     # (change requires restart)
 
 
+allow_a_half_consensus = off
+                                    # Quorum exists if more than or equal to a half of even number nodes are alive.
+                                    # (change requires restart)
 # - Lifecheck Setting -
 
 # -- common --
diff --git a/src/sample/pgpool.conf.sample-stream b/src/sample/pgpool.conf.sample-stream
index f76d5cc1..96804f0a 100644
--- a/src/sample/pgpool.conf.sample-stream
+++ b/src/sample/pgpool.conf.sample-stream
@@ -644,6 +644,9 @@ allow_multiple_failover_requests_from_node = off
                                     # (change requires restart)
 
 
+allow_a_half_consensus = off
+                                    # Quorum exists if more than or equal to a half of even number nodes are alive.
+                                    # (change requires restart)
 # - Lifecheck Setting -
 
 # -- common --
diff --git a/src/watchdog/watchdog.c b/src/watchdog/watchdog.c
index 403a641e..a0e21b3c 100644
--- a/src/watchdog/watchdog.c
+++ b/src/watchdog/watchdog.c
@@ -5,7 +5,7 @@
  * pgpool: a language independent connection pool server for PostgreSQL
  * written by Tatsuo Ishii
  *
- * Copyright (c) 2003-2016	PgPool Global Development Group
+ * Copyright (c) 2003-2019	PgPool Global Development Group
  *
  * Permission to use, copy, modify, and distribute this software and
  * its documentation for any purpose and without fee is hereby
@@ -420,7 +420,8 @@ static void service_internal_command(void);
 static unsigned int get_next_commandID(void);
 static WatchdogNode * parse_node_info_message(WDPacketData * pkt, char **authkey);
 static void update_quorum_status(void);
-static int	get_mimimum_nodes_required_for_quorum(void);
+static int	get_mimimum_remote_nodes_required_for_quorum(void);
+static int	get_minimum_votes_to_resolve_consensus(void);
 
 static bool write_packet_to_socket(int sock, WDPacketData * pkt, bool ipcPacket);
 static int	read_sockets(fd_set *rmask, int pending_fds_count);
@@ -2384,7 +2385,7 @@ static WDFailoverCMDResults compute_failover_consensus(POOL_REQUEST_KIND reqKind
 		bool		duplicate = false;
 		WDFailoverObject *failoverObj = add_failover(reqKind, node_id_list, node_count, wdNode, *flags, &duplicate);
 
-		if (failoverObj->request_count <= get_mimimum_nodes_required_for_quorum())
+		if (failoverObj->request_count < get_minimum_votes_to_resolve_consensus())
 		{
 			ereport(LOG, (
 						  errmsg("failover requires the majority vote, waiting for consensus"),
@@ -6333,14 +6334,19 @@ update_quorum_status(void)
 {
 	int			quorum_status = g_cluster.quorum_status;
 
-	if (g_cluster.clusterMasterInfo.standby_nodes_count > get_mimimum_nodes_required_for_quorum())
+	if (g_cluster.clusterMasterInfo.standby_nodes_count > get_mimimum_remote_nodes_required_for_quorum())
 	{
 		g_cluster.quorum_status = 1;
 	}
-	else if (g_cluster.clusterMasterInfo.standby_nodes_count == get_mimimum_nodes_required_for_quorum())
+	else if (g_cluster.clusterMasterInfo.standby_nodes_count == get_mimimum_remote_nodes_required_for_quorum())
 	{
 		if (g_cluster.remoteNodeCount % 2 != 0)
-			g_cluster.quorum_status = 0;	/* on the edge */
+		{
+			if (pool_config->allow_a_half_consensus)
+				g_cluster.quorum_status = 0;	/* on the edge */
+			else
+				g_cluster.quorum_status = -1;
+		}
 		else
 			g_cluster.quorum_status = 1;
 	}
@@ -6355,24 +6361,76 @@ update_quorum_status(void)
 	}
 }
 
-/* returns the minimum number of remote nodes required for quorum */
+/*
+ * returns the minimum number of remote nodes required for quorum
+ */
 static int
-get_mimimum_nodes_required_for_quorum(void)
+get_mimimum_remote_nodes_required_for_quorum(void)
 {
 	/*
 	 * Even numner of remote nodes, That means total number of nodes are odd,
-	 * so minimum quorum is just remote/2
+	 * so minimum quorum is just remote/2.
 	 */
 	if (g_cluster.remoteNodeCount % 2 == 0)
-		return (g_cluster.remoteNodeCount / 2);
+			return (g_cluster.remoteNodeCount / 2);
 
 	/*
-	 * Total nodes including self are even, So we consider 50% nodes as
-	 * quorum, should we?
+	 * Total nodes including self are even, So we return 50% nodes as quorum
+	 * requirements
 	 */
 	return ((g_cluster.remoteNodeCount - 1) / 2);
 }
 
+/*
+ * returns the minimum number of votes required for consensus
+ */
+static int
+get_minimum_votes_to_resolve_consensus(void)
+{
+	/*
+	 * Since get_mimimum_remote_nodes_required_for_quorum() returns
+	 * the number of remote nodes required to complete the quorum
+	 * that is always one less than the total number of nodes required
+	 * for the cluster to build quorum or consensus, reason being
+	 * in get_mimimum_remote_nodes_required_for_quorum()
+	 * we always consider the local node as a valid pre-casted vote.
+	 * But when it comes to count the number of votes required to build
+	 * consensus for any type of decision, for example for building the
+	 * consensus on backend failover, the local node can vote on either
+	 * side. So it's vote is not explicitly counted and for the consensus
+	 * we actually need one more vote than the total number of remote nodes
+	 * required for the quorum
+	 *
+	 * For example
+	 * If Total nodes in cluster = 4
+	 * 		remote node will be = 3
+	 * 		get_mimimum_remote_nodes_required_for_quorum() return = 1
+	 *		Minimum number of votes required for consensu will be
+	 *
+	 *		if(pool_config->allow_a_half_consensus = true)
+	 *			(exact 50% n/2) ==> 4/2 = 2
+	 *
+	 *		if(pool_config->allow_a_half_consensus = false)
+	 *			(exact 50% +1 ==> (n/2)+1) ==> (4/2)+1 = 3
+	 *
+	 */
+
+	int required_node_count = get_mimimum_remote_nodes_required_for_quorum()  + 1;
+	/*
+	 * When the total number of nodes in the watchdog cluster including the
+	 * local node are even, The number of votes required for the consensus
+	 * depends on the allow_a_half_consensus.
+	 * So for even number of nodes when allow_a_half_consensus is not allowed
+	 * than we would nedd one more vote than exact 50%
+	 */
+	if (g_cluster.remoteNodeCount % 2 != 0)
+	{
+		if (pool_config->allow_a_half_consensus == false)
+			required_node_count += 1;
+	}
+
+	return required_node_count;
+}
 
 /*
  * sets the state of local watchdog node, and fires a state change event