allow online change primary_conninfo

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index db1a2d4..c3f19d8 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3797,7 +3797,8 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
         </listitem>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c80b14e..9d66455 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -11848,8 +11848,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 									 tli, curFileTLI);
 						}
 						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
+						RequestXLogStreaming(tli, ptr);
 						receivedUpto = 0;
 					}
 
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 9643c2e..14cf279 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -143,6 +143,7 @@ static void XLogWalRcvFlush(bool dying);
 static void XLogWalRcvSendReply(bool force, bool requestReply);
 static void XLogWalRcvSendHSFeedback(bool immed);
 static void ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime);
+static void ProcessWalRcvSigHup(void);
 
 /* Signal handlers */
 static void WalRcvSigHupHandler(SIGNAL_ARGS);
@@ -188,9 +189,7 @@ DisableWalRcvImmediateExit(void)
 void
 WalReceiverMain(void)
 {
-	char		conninfo[MAXCONNINFO];
 	char	   *tmp_conninfo;
-	char		slotname[NAMEDATALEN];
 	XLogRecPtr	startpoint;
 	TimeLineID	startpointTLI;
 	TimeLineID	primaryTLI;
@@ -250,8 +249,6 @@ WalReceiverMain(void)
 
 	/* Fetch information required to start streaming */
 	walrcv->ready_to_display = false;
-	strlcpy(conninfo, (char *) walrcv->conninfo, MAXCONNINFO);
-	strlcpy(slotname, (char *) walrcv->slotname, NAMEDATALEN);
 	startpoint = walrcv->receiveStart;
 	startpointTLI = walrcv->receiveStartTLI;
 
@@ -293,7 +290,7 @@ WalReceiverMain(void)
 
 	/* Establish the connection to the primary for XLOG streaming */
 	EnableWalRcvImmediateExit();
-	wrconn = walrcv_connect(conninfo, false, "walreceiver", &err);
+	wrconn = walrcv_connect(PrimaryConnInfo, false, "walreceiver", &err);
 	if (!wrconn)
 		ereport(ERROR,
 				(errmsg("could not connect to the primary server: %s", err)));
@@ -387,7 +384,7 @@ WalReceiverMain(void)
 		 */
 		options.logical = false;
 		options.startpoint = startpoint;
-		options.slotname = slotname[0] != '\0' ? slotname : NULL;
+		options.slotname = PrimarySlotName[0] != '\0' ? PrimarySlotName : NULL;
 		options.proto.physical.startpointTLI = startpointTLI;
 		ThisTimeLineID = startpointTLI;
 		if (walrcv_startstreaming(wrconn, &options))
@@ -436,8 +433,7 @@ WalReceiverMain(void)
 				if (got_SIGHUP)
 				{
 					got_SIGHUP = false;
-					ProcessConfigFile(PGC_SIGHUP);
-					XLogWalRcvSendHSFeedback(true);
+					ProcessWalRcvSigHup();
 				}
 
 				/* See if we can read data immediately */
@@ -1317,6 +1313,41 @@ ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
 }
 
 /*
+ * Actual processing SIGHUP signal
+ */
+static void
+ProcessWalRcvSigHup(void)
+{
+	char	*conninfo = pstrdup(PrimaryConnInfo);
+	char	*slotname = pstrdup(PrimarySlotName);
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * If primary_conninfo has been changed while walreceiver is running,
+	 * shut down walreceiver so that a new walreceiver is started and
+	 * initiates replication with the new connection information.
+	 */
+	if (strcmp(conninfo, PrimaryConnInfo) != 0)
+		ereport(FATAL,
+				(errcode(ERRCODE_ADMIN_SHUTDOWN),
+				 errmsg("closing replication connection because primary_conninfo was changed")));
+
+	/*
+	 * And the same for primary_slot_name.
+	 */
+	if (strcmp(slotname, PrimarySlotName) != 0)
+		ereport(FATAL,
+				(errcode(ERRCODE_ADMIN_SHUTDOWN),
+				 errmsg("closing replication connection because primary_slot_name was changed")));
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	XLogWalRcvSendHSFeedback(true);
+}
+
+/*
  * Wake up the walreceiver main loop.
  *
  * This is called by the startup process whenever interesting xlog records
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 67b1a07..be37241 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -215,13 +215,10 @@ ShutdownWalRcv(void)
 /*
  * Request postmaster to start walreceiver.
  *
- * recptr indicates the position where streaming should begin, conninfo
- * is a libpq connection string to use, and slotname is, optionally, the name
- * of a replication slot to acquire.
+ * recptr indicates the position where streaming should begin
  */
 void
-RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
-					 const char *slotname)
+RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr)
 {
 	WalRcvData *walrcv = WalRcv;
 	bool		launch = false;
@@ -243,16 +240,6 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	Assert(walrcv->walRcvState == WALRCV_STOPPED ||
 		   walrcv->walRcvState == WALRCV_WAITING);
 
-	if (conninfo != NULL)
-		strlcpy((char *) walrcv->conninfo, conninfo, MAXCONNINFO);
-	else
-		walrcv->conninfo[0] = '\0';
-
-	if (slotname != NULL)
-		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
-	else
-		walrcv->slotname[0] = '\0';
-
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
 		launch = true;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6497393..301a4b5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3435,7 +3435,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3446,7 +3446,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index 5913b58..510c7f6 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -104,7 +104,7 @@ typedef struct
 	TimestampTz latestWalEndTime;
 
 	/*
-	 * connection string; initially set to connect to the primary, and later
+	 * connection string used by runned walreceiver;
 	 * clobbered to hide security-sensitive fields.
 	 */
 	char		conninfo[MAXCONNINFO];
@@ -117,8 +117,7 @@ typedef struct
 	int			sender_port;
 
 	/*
-	 * replication slot name; is also used for walreceiver to connect with the
-	 * primary
+	 * replication slot name used by runned walreceiver
 	 */
 	char		slotname[NAMEDATALEN];
 
@@ -306,8 +305,7 @@ extern void WalRcvShmemInit(void);
 extern void ShutdownWalRcv(void);
 extern bool WalRcvStreaming(void);
 extern bool WalRcvRunning(void);
-extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
-					 const char *conninfo, const char *slotname);
+extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr);
 extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
 extern int	GetReplicationApplyDelay(void);
 extern int	GetReplicationTransferLatency(void);
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index beb4555..5b9bc77 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 26;
+use Test::More tests => 27;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -146,7 +146,7 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+$node_standby_2->reload; # should have effect without restart
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -282,3 +282,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 4a7121a..bce99ce 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3796,9 +3796,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          <application>walreceiver</application> will be restarted after
+          <varname>primary_conninfo</varname> was changed.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3813,9 +3818,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          <application>walreceiver</application> will be restarted after
+          <varname>primary_slot_name</varname> was changed.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 9643c2e..cdd9f40 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -113,6 +113,12 @@ static StringInfoData reply_message;
 static StringInfoData incoming_message;
 
 /*
+ * Copy of current WalReceiverConn connection info (not clobbered)
+ */
+static char current_conninfo[MAXCONNINFO];
+static char current_slotname[NAMEDATALEN];
+
+/*
  * About SIGTERM handling:
  *
  * We can't just exit(1) within SIGTERM signal handler, because the signal
@@ -143,6 +149,7 @@ static void XLogWalRcvFlush(bool dying);
 static void XLogWalRcvSendReply(bool force, bool requestReply);
 static void XLogWalRcvSendHSFeedback(bool immed);
 static void ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime);
+static void ProcessWalRcvSigHup(void);
 
 /* Signal handlers */
 static void WalRcvSigHupHandler(SIGNAL_ARGS);
@@ -188,9 +195,7 @@ DisableWalRcvImmediateExit(void)
 void
 WalReceiverMain(void)
 {
-	char		conninfo[MAXCONNINFO];
 	char	   *tmp_conninfo;
-	char		slotname[NAMEDATALEN];
 	XLogRecPtr	startpoint;
 	TimeLineID	startpointTLI;
 	TimeLineID	primaryTLI;
@@ -250,8 +255,8 @@ WalReceiverMain(void)
 
 	/* Fetch information required to start streaming */
 	walrcv->ready_to_display = false;
-	strlcpy(conninfo, (char *) walrcv->conninfo, MAXCONNINFO);
-	strlcpy(slotname, (char *) walrcv->slotname, NAMEDATALEN);
+	strlcpy(current_conninfo, (char *) walrcv->conninfo, MAXCONNINFO);
+	strlcpy(current_slotname, (char *) walrcv->slotname, NAMEDATALEN);
 	startpoint = walrcv->receiveStart;
 	startpointTLI = walrcv->receiveStartTLI;
 
@@ -293,7 +298,7 @@ WalReceiverMain(void)
 
 	/* Establish the connection to the primary for XLOG streaming */
 	EnableWalRcvImmediateExit();
-	wrconn = walrcv_connect(conninfo, false, "walreceiver", &err);
+	wrconn = walrcv_connect(current_conninfo, false, "walreceiver", &err);
 	if (!wrconn)
 		ereport(ERROR,
 				(errmsg("could not connect to the primary server: %s", err)));
@@ -387,7 +392,7 @@ WalReceiverMain(void)
 		 */
 		options.logical = false;
 		options.startpoint = startpoint;
-		options.slotname = slotname[0] != '\0' ? slotname : NULL;
+		options.slotname = current_slotname[0] != '\0' ? current_slotname : NULL;
 		options.proto.physical.startpointTLI = startpointTLI;
 		ThisTimeLineID = startpointTLI;
 		if (walrcv_startstreaming(wrconn, &options))
@@ -436,8 +441,7 @@ WalReceiverMain(void)
 				if (got_SIGHUP)
 				{
 					got_SIGHUP = false;
-					ProcessConfigFile(PGC_SIGHUP);
-					XLogWalRcvSendHSFeedback(true);
+					ProcessWalRcvSigHup();
 				}
 
 				/* See if we can read data immediately */
@@ -1317,6 +1321,35 @@ ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
 }
 
 /*
+ * Actual processing SIGHUP signal
+ */
+static void
+ProcessWalRcvSigHup(void)
+{
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * If primary_conninfo has been changed while walreceiver is running,
+	 * shut down walreceiver so that a new walreceiver is started and
+	 * initiates replication with the new connection information.
+	 */
+	if (strcmp(current_conninfo, PrimaryConnInfo) != 0)
+		ereport(FATAL,
+				(errcode(ERRCODE_ADMIN_SHUTDOWN),
+				 errmsg("closing replication connection because primary_conninfo was changed")));
+
+	/*
+	 * And the same for primary_slot_name.
+	 */
+	if (strcmp(current_slotname, PrimarySlotName) != 0)
+		ereport(FATAL,
+				(errcode(ERRCODE_ADMIN_SHUTDOWN),
+				 errmsg("closing replication connection because primary_slot_name was changed")));
+
+	XLogWalRcvSendHSFeedback(true);
+}
+
+/*
  * Wake up the walreceiver main loop.
  *
  * This is called by the startup process whenever interesting xlog records
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6fe1939..09948ee 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3448,7 +3448,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3459,7 +3459,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index beb4555..07ac964 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 26;
+use Test::More tests => 27;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -146,7 +146,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -282,3 +284,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 9b7a7388d5..af68afa715 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3827,9 +3827,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_conninfo</varname>
+          was changed.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3844,9 +3849,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_slot_name</varname>
+          was changed.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 2e90944ad5..05b90d00a4 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -112,6 +112,12 @@ static struct
 static StringInfoData reply_message;
 static StringInfoData incoming_message;
 
+/*
+ * Copy of current WalReceiverConn connection info (not clobbered)
+ */
+static char current_conninfo[MAXCONNINFO];
+static char current_slotname[NAMEDATALEN];
+
 /*
  * About SIGTERM handling:
  *
@@ -143,6 +149,7 @@ static void XLogWalRcvFlush(bool dying);
 static void XLogWalRcvSendReply(bool force, bool requestReply);
 static void XLogWalRcvSendHSFeedback(bool immed);
 static void ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime);
+static void ProcessWalRcvSigHup(void);
 
 /* Signal handlers */
 static void WalRcvSigHupHandler(SIGNAL_ARGS);
@@ -188,9 +195,7 @@ DisableWalRcvImmediateExit(void)
 void
 WalReceiverMain(void)
 {
-	char		conninfo[MAXCONNINFO];
 	char	   *tmp_conninfo;
-	char		slotname[NAMEDATALEN];
 	XLogRecPtr	startpoint;
 	TimeLineID	startpointTLI;
 	TimeLineID	primaryTLI;
@@ -250,8 +255,8 @@ WalReceiverMain(void)
 
 	/* Fetch information required to start streaming */
 	walrcv->ready_to_display = false;
-	strlcpy(conninfo, (char *) walrcv->conninfo, MAXCONNINFO);
-	strlcpy(slotname, (char *) walrcv->slotname, NAMEDATALEN);
+	strlcpy(current_conninfo, (char *) walrcv->conninfo, MAXCONNINFO);
+	strlcpy(current_slotname, (char *) walrcv->slotname, NAMEDATALEN);
 	startpoint = walrcv->receiveStart;
 	startpointTLI = walrcv->receiveStartTLI;
 
@@ -293,7 +298,7 @@ WalReceiverMain(void)
 
 	/* Establish the connection to the primary for XLOG streaming */
 	EnableWalRcvImmediateExit();
-	wrconn = walrcv_connect(conninfo, false, "walreceiver", &err);
+	wrconn = walrcv_connect(current_conninfo, false, "walreceiver", &err);
 	if (!wrconn)
 		ereport(ERROR,
 				(errmsg("could not connect to the primary server: %s", err)));
@@ -387,7 +392,7 @@ WalReceiverMain(void)
 		 */
 		options.logical = false;
 		options.startpoint = startpoint;
-		options.slotname = slotname[0] != '\0' ? slotname : NULL;
+		options.slotname = current_slotname[0] != '\0' ? current_slotname : NULL;
 		options.proto.physical.startpointTLI = startpointTLI;
 		ThisTimeLineID = startpointTLI;
 		if (walrcv_startstreaming(wrconn, &options))
@@ -436,8 +441,7 @@ WalReceiverMain(void)
 				if (got_SIGHUP)
 				{
 					got_SIGHUP = false;
-					ProcessConfigFile(PGC_SIGHUP);
-					XLogWalRcvSendHSFeedback(true);
+					ProcessWalRcvSigHup();
 				}
 
 				/* See if we can read data immediately */
@@ -1316,6 +1320,37 @@ ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
 	}
 }
 
+/*
+ * Actual processing SIGHUP signal
+ */
+static void
+ProcessWalRcvSigHup(void)
+{
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * If primary_conninfo has been changed while walreceiver is running,
+	 * shut down walreceiver so that a new walreceiver is started and
+	 * initiates replication with the new connection information.
+	 */
+	if (strcmp(current_conninfo, PrimaryConnInfo) != 0)
+		ereport(FATAL,
+				(errcode(ERRCODE_ADMIN_SHUTDOWN),
+				 errmsg("terminating walreceiver process due to change of primary_conninfo"),
+				 errdetail("In a moment starts streaming WAL with new configuration.")));
+
+	/*
+	 * And the same for primary_slot_name.
+	 */
+	if (strcmp(current_slotname, PrimarySlotName) != 0)
+		ereport(FATAL,
+				(errcode(ERRCODE_ADMIN_SHUTDOWN),
+				 errmsg("terminating walreceiver process due to change of primary_slot_name"),
+				 errdetail("In a moment starts streaming WAL with new configuration.")));
+
+	XLogWalRcvSendHSFeedback(true);
+}
+
 /*
  * Wake up the walreceiver main loop.
  *
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 8681ada33a..ab3cff2620 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3484,7 +3484,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3495,7 +3495,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index beb45551a2..07ac9642ba 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 26;
+use Test::More tests => 27;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -146,7 +146,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -282,3 +284,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 8bd57f376b..d7b75e462a 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3838,9 +3838,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_conninfo</varname>
+          was changed.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3855,9 +3860,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_slot_name</varname>
+          was changed.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index ecd12fc53a..6a64a27a51 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -12137,6 +12137,36 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * we need shutdown running walreceiver if replication settings was
+	 * changed. walreceiver will be started with new settings in next
+	 * WaitForWALToBecomeAvailable iteration
+	 */
+	if ((strcmp(conninfo, PrimaryConnInfo) != 0 ||
+		 strcmp(slotname, PrimarySlotName) != 0) &&
+		WalRcvRunning())
+	{
+		ereport(LOG,
+				(errmsg("terminating walreceiver process due to change of %s",
+						strcmp(conninfo, PrimaryConnInfo) != 0 ? "primary_conninfo" : "primary_slot_name"),
+				 errdetail("In a moment starts streaming WAL with new configuration.")));
+
+		ShutdownWalRcv();
+		lastSourceFailed = true;
+	}
+
+	pfree(conninfo);
+	pfree(slotname);
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..9bf5c792fe 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -147,7 +147,7 @@ HandleStartupProcInterrupts(void)
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 156d147c85..87bd7443ef 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3485,7 +3485,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3496,7 +3496,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index f90a6a9139..75ec605a3f 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -318,6 +318,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index beb45551a2..07ac9642ba 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 26;
+use Test::More tests => 27;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -146,7 +146,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -282,3 +284,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 8bd57f376b..d7b75e462a 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3838,9 +3838,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_conninfo</varname>
+          was changed.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3855,9 +3860,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_slot_name</varname>
+          was changed.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index ecd12fc53a..8a77ebb0d3 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -12137,6 +12137,44 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * we need shutdown running walreceiver if replication settings was
+	 * changed. walreceiver will be started with new settings in next
+	 * WaitForWALToBecomeAvailable iteration
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	if ((conninfoChanged || slotnameChanged) && WalRcvRunning())
+	{
+		if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("terminating walreceiver process due to change of primary_conninfo and primary_slot_name"),
+					 errdetail("The WAL receiver is going to be restarted with the new configuration")));
+		else
+			ereport(LOG,
+					(errmsg("terminating walreceiver process due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name"),
+					 errdetail("The WAL receiver is going to be restarted with the new configuration")));
+
+		ShutdownWalRcv();
+		lastSourceFailed = true;
+	}
+
+	pfree(conninfo);
+	pfree(slotname);
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..9bf5c792fe 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -147,7 +147,7 @@ HandleStartupProcInterrupts(void)
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 156d147c85..87bd7443ef 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3485,7 +3485,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3496,7 +3496,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index f90a6a9139..75ec605a3f 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -318,6 +318,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index beb45551a2..07ac9642ba 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 26;
+use Test::More tests => 27;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -146,7 +146,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -282,3 +284,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index ecd12fc53a..daddaeb236 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -798,10 +798,11 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
  * different from readSource in that this is always set, even when we don't
  * currently have a WAL file open. If lastSourceFailed is set, our last
  * attempt to read from currentSource failed, and we should try another source
- * next.
+ * next. If pendingRestartSource is set we want restart current source
  */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
+static bool pendingRestartSource = false;
 
 typedef struct XLogPageReadPrivate
 {
@@ -11828,48 +11829,6 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
@@ -11969,10 +11928,83 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 				 lastSourceFailed ? "failure" : "success");
 
 		/*
-		 * We've now handled possible failure. Try to read from the chosen
-		 * source.
+		 * Prepare to read from the chosen source if we asked restart source
+		 * or last source was failed
+		 */
+		if (pendingRestartSource || lastSourceFailed)
+		{
+			/*
+			 * make sure that walreceiver is not active. this is needed for
+			 * all supported sources
+			 */
+			if (WalRcvRunning())
+				ShutdownWalRcv();
+
+			switch (currentSource)
+			{
+				case XLOG_FROM_ARCHIVE:
+				case XLOG_FROM_PG_WAL:
+
+					/*
+					 * We do not need additional actions here
+					 */
+					break;
+
+				case XLOG_FROM_STREAM:
+
+					/*
+					 * If primary_conninfo is set, launch walreceiver to try
+					 * to stream the missing WAL.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+					break;
+				default:
+					elog(ERROR, "unexpected WAL source %d", currentSource);
+			}
+		}
+
+		/*
+		 * We've now handled possible failure and pending source restart. Try
+		 * to read from the chosen source.
 		 */
 		lastSourceFailed = false;
+		pendingRestartSource = false;
 
 		switch (currentSource)
 		{

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 6d42b7afe7..bf37cc4637 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3839,9 +3839,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_conninfo</varname>
+          was changed.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3856,9 +3861,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_slot_name</varname>
+          was changed.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index daddaeb236..156954b7d9 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -12169,6 +12169,42 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart XLOG_FROM_STREAM source if replication settings was
+	 * changed
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of primary_conninfo and primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingRestartSource = true;
+	}
+
+	pfree(conninfo);
+	pfree(slotname);
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..9bf5c792fe 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -147,7 +147,7 @@ HandleStartupProcInterrupts(void)
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 156d147c85..87bd7443ef 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3485,7 +3485,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3496,7 +3496,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index f90a6a9139..75ec605a3f 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -318,6 +318,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index beb45551a2..07ac9642ba 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 26;
+use Test::More tests => 27;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -146,7 +146,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -282,3 +284,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 84341a30e5..054be17e08 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3916,9 +3916,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_conninfo</varname>
+          was changed.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3933,9 +3938,14 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          WAL receiver will be restarted after <varname>primary_slot_name</varname>
+          was changed.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 3e2c4e3e5b..964989432c 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -12125,6 +12125,42 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart XLOG_FROM_STREAM source if replication settings was
+	 * changed
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of primary_conninfo and primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingRestartSource = true;
+	}
+
+	pfree(conninfo);
+	pfree(slotname);
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..9bf5c792fe 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -147,7 +147,7 @@ HandleStartupProcInterrupts(void)
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 92c4fee8f8..e54d8e7172 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3571,7 +3571,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3582,7 +3582,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d519252aad..9e49020b19 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 3c743d7d7c..ae80f4df3a 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 32;
+use Test::More tests => 33;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -344,3 +346,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 13e0d2366f..3e2c4e3e5b 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -798,10 +798,11 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
  * different from readSource in that this is always set, even when we don't
  * currently have a WAL file open. If lastSourceFailed is set, our last
  * attempt to read from currentSource failed, and we should try another source
- * next.
+ * next. If pendingRestartSource is set we want restart current source
  */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
+static bool pendingRestartSource = false;
 
 typedef struct XLogPageReadPrivate
 {
@@ -11784,48 +11785,6 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
@@ -11925,10 +11884,83 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 				 lastSourceFailed ? "failure" : "success");
 
 		/*
-		 * We've now handled possible failure. Try to read from the chosen
-		 * source.
+		 * Prepare to read from the chosen source if we asked restart source
+		 * or last source was failed
+		 */
+		if (pendingRestartSource || lastSourceFailed)
+		{
+			/*
+			 * make sure that walreceiver is not active. this is needed for
+			 * all supported sources
+			 */
+			if (WalRcvRunning())
+				ShutdownWalRcv();
+
+			switch (currentSource)
+			{
+				case XLOG_FROM_ARCHIVE:
+				case XLOG_FROM_PG_WAL:
+
+					/*
+					 * We do not need additional actions here
+					 */
+					break;
+
+				case XLOG_FROM_STREAM:
+
+					/*
+					 * If primary_conninfo is set, launch walreceiver to try
+					 * to stream the missing WAL.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+					break;
+				default:
+					elog(ERROR, "unexpected WAL source %d", currentSource);
+			}
+		}
+
+		/*
+		 * We've now handled possible failure and pending source restart. Try
+		 * to read from the chosen source.
 		 */
 		lastSourceFailed = false;
+		pendingRestartSource = false;
 
 		switch (currentSource)
 		{

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 89284dc5c0..b36749fe91 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3929,9 +3929,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_conninfo</varname>.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3946,9 +3950,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index e651a841bb..4eed462f34 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -803,6 +803,12 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11787,48 +11793,6 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
@@ -11928,10 +11892,66 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 				 lastSourceFailed ? "failure" : "success");
 
 		/*
-		 * We've now handled possible failure. Try to read from the chosen
-		 * source.
+		 * Request walreceiver to start if we switch from another source or if
+		 * we need to change walreceiver connection configuration.
+		 */
+		if (currentSource == XLOG_FROM_STREAM && (lastSourceFailed || pendingWalRcvRestart))
+		{
+			/*
+			 * Ensure walreceiver is not running
+			 */
+			if (WalRcvRunning())
+				ShutdownWalRcv();
+
+			/*
+			 * If primary_conninfo is set, launch walreceiver to try to stream
+			 * the missing WAL.
+			 *
+			 * If fetching_ckpt is true, RecPtr points to the initial
+			 * checkpoint location. In that case, we use RedoStartLSN as the
+			 * streaming start position instead of RecPtr, so that when we
+			 * later jump backwards to start redo at RedoStartLSN, we will
+			 * have the logs streamed already.
+			 */
+			if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+			{
+				XLogRecPtr	ptr;
+				TimeLineID	tli;
+
+				if (fetching_ckpt)
+				{
+					ptr = RedoStartLSN;
+					tli = ControlFile->checkPointCopy.ThisTimeLineID;
+				}
+				else
+				{
+					ptr = RecPtr;
+
+					/*
+					 * Use the record begin position to determine the TLI,
+					 * rather than the position we're reading.
+					 */
+					tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+					if (curFileTLI > 0 && tli < curFileTLI)
+						elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+							 (uint32) (tliRecPtr >> 32),
+							 (uint32) tliRecPtr,
+							 tli, curFileTLI);
+				}
+				curFileTLI = tli;
+				RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+									 PrimarySlotName);
+				receivedUpto = 0;
+			}
+		}
+
+		/*
+		 * We've now handled possible failure and configuration change. Try to
+		 * read from the chosen source.
 		 */
 		lastSourceFailed = false;
+		pendingWalRcvRestart = false;
 
 		switch (currentSource)
 		{
@@ -12096,6 +12116,45 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of primary_conninfo and primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingWalRcvRestart = true;
+	}
+
+	pfree(conninfo);
+	pfree(slotname);
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..62492daf6b 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -142,12 +142,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 90ffd89339..5ffe593517 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3558,7 +3558,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3569,7 +3569,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d519252aad..9e49020b19 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 3c743d7d7c..ae80f4df3a 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 32;
+use Test::More tests => 33;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -344,3 +346,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 6612f95f9f..1fa48058e8 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3929,9 +3929,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3946,9 +3952,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index b7ff004234..743cae079e 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -803,6 +803,12 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11787,48 +11793,6 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
@@ -11928,10 +11892,66 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 				 lastSourceFailed ? "failure" : "success");
 
 		/*
-		 * We've now handled possible failure. Try to read from the chosen
-		 * source.
+		 * Request walreceiver to start if we switch from another source or if
+		 * we need to change walreceiver connection configuration.
+		 */
+		if (currentSource == XLOG_FROM_STREAM && (lastSourceFailed || pendingWalRcvRestart))
+		{
+			/*
+			 * Ensure walreceiver is not running
+			 */
+			if (WalRcvRunning())
+				ShutdownWalRcv();
+
+			/*
+			 * If primary_conninfo is set, launch walreceiver to try to stream
+			 * the missing WAL.
+			 *
+			 * If fetching_ckpt is true, RecPtr points to the initial
+			 * checkpoint location. In that case, we use RedoStartLSN as the
+			 * streaming start position instead of RecPtr, so that when we
+			 * later jump backwards to start redo at RedoStartLSN, we will
+			 * have the logs streamed already.
+			 */
+			if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+			{
+				XLogRecPtr	ptr;
+				TimeLineID	tli;
+
+				if (fetching_ckpt)
+				{
+					ptr = RedoStartLSN;
+					tli = ControlFile->checkPointCopy.ThisTimeLineID;
+				}
+				else
+				{
+					ptr = RecPtr;
+
+					/*
+					 * Use the record begin position to determine the TLI,
+					 * rather than the position we're reading.
+					 */
+					tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+					if (curFileTLI > 0 && tli < curFileTLI)
+						elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+							 (uint32) (tliRecPtr >> 32),
+							 (uint32) tliRecPtr,
+							 tli, curFileTLI);
+				}
+				curFileTLI = tli;
+				RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+									 PrimarySlotName);
+				receivedUpto = 0;
+			}
+		}
+
+		/*
+		 * We've now handled possible failure and configuration change. Try to
+		 * read from the chosen source.
 		 */
 		lastSourceFailed = false;
+		pendingWalRcvRestart = false;
 
 		switch (currentSource)
 		{
@@ -12096,6 +12116,45 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of primary_conninfo and primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingWalRcvRestart = true;
+	}
+
+	pfree(conninfo);
+	pfree(slotname);
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..62492daf6b 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -142,12 +142,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 6abc780778..59834b9df8 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -644,7 +644,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 90ffd89339..5ffe593517 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3558,7 +3558,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3569,7 +3569,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 0fc23e3a61..c25e406b9e 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -308,9 +308,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d519252aad..9e49020b19 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 3c743d7d7c..ae80f4df3a 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 32;
+use Test::More tests => 33;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -344,3 +346,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 6876537b62..61b235f8f7 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -11881,10 +11881,12 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 * obtaining the requested WAL. We're going to loop back
 					 * and retry from the archive, but if it hasn't been long
 					 * since last attempt, sleep wal_retrieve_retry_interval
-					 * milliseconds to avoid busy-waiting.
+					 * milliseconds to avoid busy-waiting. We don't wait if
+					 * explicitly requested to restart.
 					 */
 					now = GetCurrentTimestamp();
-					if (!TimestampDifferenceExceeds(last_fail_time, now,
+					if (!pendingWalRcvRestart &&
+						!TimestampDifferenceExceeds(last_fail_time, now,
 													wal_retrieve_retry_interval))
 					{
 						long		secs,
@@ -11905,6 +11907,17 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					}
 					last_fail_time = now;
 					currentSource = XLOG_FROM_ARCHIVE;
+
+					/*
+					 * If wal receiver is requested to restart, we skip the
+					 * next XLOG_FROM_ARCHIVE to immediately starting it.
+					 */
+					if (pendingWalRcvRestart)
+					{
+						lastSourceFailed = true;
+						continue;
+					}
+
 					break;
 
 				default:

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 6612f95f9f..1fa48058e8 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3929,9 +3929,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -3946,9 +3952,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index b7ff004234..f0e47cc663 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -803,6 +803,12 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11756,12 +11762,13 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 		int			oldSource = currentSource;
 
 		/*
-		 * First check if we failed to read from the current source, and
+		 * First check if we failed to read from the current source or if
+		 * we want to restart wal receiver, and
 		 * advance the state machine if so. The failure to read might've
 		 * happened outside this function, e.g when a CRC check fails on a
 		 * record, or within this loop.
 		 */
-		if (lastSourceFailed)
+		if (lastSourceFailed || pendingWalRcvRestart)
 		{
 			switch (currentSource)
 			{
@@ -11862,6 +11869,17 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (WalRcvStreaming())
 						ShutdownWalRcv();
 
+					/*
+					 * If wal receiver is requested to restart, we skip the
+					 * next XLOG_FROM_ARCHIVE to immediately starting it.
+					 */
+					if (pendingWalRcvRestart)
+					{
+						lastSourceFailed = true;
+						currentSource = XLOG_FROM_ARCHIVE;
+						continue;
+					}
+
 					/*
 					 * Before we sleep, re-scan for possible new timelines if
 					 * we were requested to recover to the latest timeline.
@@ -11881,7 +11899,8 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					 * obtaining the requested WAL. We're going to loop back
 					 * and retry from the archive, but if it hasn't been long
 					 * since last attempt, sleep wal_retrieve_retry_interval
-					 * milliseconds to avoid busy-waiting.
+					 * milliseconds to avoid busy-waiting. We don't wait if
+					 * explicitly requested to restart.
 					 */
 					now = GetCurrentTimestamp();
 					if (!TimestampDifferenceExceeds(last_fail_time, now,
@@ -11922,16 +11941,17 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 				currentSource = XLOG_FROM_ARCHIVE;
 		}
 
-		if (currentSource != oldSource)
+		if (currentSource != oldSource && !pendingWalRcvRestart)
 			elog(DEBUG2, "switched WAL source from %s to %s after %s",
 				 xlogSourceNames[oldSource], xlogSourceNames[currentSource],
 				 lastSourceFailed ? "failure" : "success");
 
 		/*
-		 * We've now handled possible failure. Try to read from the chosen
-		 * source.
+		 * We've now handled possible failure and configuration change. Try to
+		 * read from the chosen source.
 		 */
 		lastSourceFailed = false;
+		pendingWalRcvRestart = false;
 
 		switch (currentSource)
 		{
@@ -12096,6 +12116,45 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of primary_conninfo and primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingWalRcvRestart = true;
+	}
+
+	pfree(conninfo);
+	pfree(slotname);
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..62492daf6b 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -142,12 +142,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 6abc780778..59834b9df8 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -644,7 +644,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 90ffd89339..5ffe593517 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3558,7 +3558,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3569,7 +3569,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 0fc23e3a61..c25e406b9e 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -308,9 +308,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d519252aad..9e49020b19 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 3c743d7d7c..ae80f4df3a 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 32;
+use Test::More tests => 33;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -344,3 +346,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 6c69eb6dd7..dba0042db6 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -11755,12 +11755,15 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		int			oldSource = currentSource;
+		bool		start_wal_receiver = false;
 
 		/*
-		 * First check if we failed to read from the current source, and
+		 * First check if we failed to read from the current source or if
+		 * we want to restart wal receiver, and
 		 * advance the state machine if so. The failure to read might've
 		 * happened outside this function, e.g when a CRC check fails on a
 		 * record, or within this loop.
+		 * Restart wal receiver if explicitly requested, too.
 		 */
 		if (lastSourceFailed)
 		{
@@ -11788,53 +11791,12 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
 					 * and move on to the next state.
 					 */
+					start_wal_receiver = true;
 					currentSource = XLOG_FROM_STREAM;
 					break;
 
@@ -11864,8 +11826,8 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						ShutdownWalRcv();
 
 					/*
-					 * Before we sleep, re-scan for possible new timelines if
-					 * we were requested to recover to the latest timeline.
+					 * Re-scan for possible new timelines if we were requested
+					 * to recover to the latest timeline.
 					 */
 					if (recoveryTargetTimeLineGoal == RECOVERY_TARGET_TIMELINE_LATEST)
 					{
@@ -11929,8 +11891,8 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 				 lastSourceFailed ? "failure" : "success");
 
 		/*
-		 * We've now handled possible failure. Try to read from the chosen
-		 * source.
+		 * We've now handled possible failure and configuration change. Try to
+		 * read from the chosen source.
 		 */
 		lastSourceFailed = false;
 
@@ -11969,9 +11931,71 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					bool		havedata;
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * shutdown wal receiver if restart is requested.
 					 */
-					if (!WalRcvStreaming())
+					if (!start_wal_receiver && pendingWalRcvRestart)
+					{
+						if (WalRcvRunning())
+							ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+						
+						start_wal_receiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (start_wal_receiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Else, check if WAL receiver is still active.
+					 */
+					else if (!WalRcvStreaming())
 					{
 						lastSourceFailed = true;
 						break;

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 0191ec84b1..587031dea8 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3983,9 +3983,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4000,9 +4006,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2e3cc51006..8eee079eb2 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -803,6 +803,12 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11773,6 +11779,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		int			oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11806,54 +11813,13 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
 					 * and move on to the next state.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -11999,7 +11965,69 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * shutdown WAL receiver if restart is requested.
+					 */
+					if (!startWalReceiver && pendingWalRcvRestart)
+					{
+						if (WalRcvRunning())
+							ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12127,6 +12155,45 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of primary_conninfo and primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 5048a2c2aa..62492daf6b 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -142,12 +142,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index f54ae7690d..8698e07f8a 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -644,7 +644,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 31a5ef0474..432296714f 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3558,7 +3558,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3569,7 +3569,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 0fc23e3a61..c25e406b9e 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -308,9 +308,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index d519252aad..9e49020b19 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 3c743d7d7c..ae80f4df3a 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 32;
+use Test::More tests => 33;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -344,3 +346,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 14992a08d7..19f36a3318 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4000,9 +4000,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4017,9 +4023,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
@@ -4137,7 +4147,11 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
         The default is on.  The only reason to turn this off would be if the
         remote instance is currently out of available replication slots.  This
-        parameter can only be set at server start.
+        parameter can only be set in the <filename>postgresql.conf</filename>
+        file or on the server command line.
+       </para>
+       <para>
+        The WAL receiver is restarted after an update of <varname>wal_receiver_create_temp_slot</varname>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 55e9294ae3..2861b9f22a 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -803,6 +803,12 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11818,6 +11824,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		int			oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11851,54 +11858,13 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
 					 * and move on to the next state.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12044,7 +12010,69 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * shutdown WAL receiver if restart is requested.
+					 */
+					if (!startWalReceiver && pendingWalRcvRestart)
+					{
+						if (WalRcvRunning())
+							ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12172,6 +12200,61 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured. We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = (tempSlot != wal_receiver_create_temp_slot);
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if ((conninfoChanged || slotnameChanged || tempSlotChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && strcmp(PrimaryConnInfo, "") == 0)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be shut down due to change of %s",
+							"primary_conninfo")));
+		else if (conninfoChanged && (slotnameChanged || tempSlotChanged))
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s and %s",
+							"primary_conninfo",
+							slotnameChanged ? "primary_slot_name" : "wal_receiver_create_temp_slot")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo"
+							: (slotnameChanged ? "primary_slot_name" : "wal_receiver_create_temp_slot"))));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index c2250d7d4e..c396fdae9a 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -101,12 +101,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 264b544194..f0651aade1 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -666,7 +666,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c4b36eb2ad..30703266a1 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1994,7 +1994,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
@@ -3643,7 +3643,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3654,7 +3654,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 4454407b7c..3dae3e9f3c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
@@ -322,7 +320,6 @@
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
 #wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
-					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 12362421d7..94009eb7be 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 3c743d7d7c..ae80f4df3a 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 32;
+use Test::More tests => 33;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -344,3 +346,21 @@ is($catalog_xmin, '',
 is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
+
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index e07dc01e80..14992a08d7 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4137,9 +4137,7 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
         The default is on.  The only reason to turn this off would be if the
         remote instance is currently out of available replication slots.  This
-        parameter can only be set in the <filename>postgresql.conf</filename>
-        file or on the server command line.  Changes only take effect when the
-        WAL receiver process starts a new connection.
+        parameter can only be set at server start.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7f4f784c0e..55e9294ae3 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -283,6 +283,7 @@ bool		StandbyModeRequested = false;
 char	   *PrimaryConnInfo = NULL;
 char	   *PrimarySlotName = NULL;
 char	   *PromoteTriggerFile = NULL;
+bool		wal_receiver_create_temp_slot = true;
 
 /* are we currently in standby mode? */
 bool		StandbyMode = false;
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a5e85d32f3..264b544194 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -73,7 +73,6 @@
 
 
 /* GUC variables */
-bool		wal_receiver_create_temp_slot;
 int			wal_receiver_status_interval;
 int			wal_receiver_timeout;
 bool		hot_standby_feedback;
@@ -349,42 +348,23 @@ WalReceiverMain(void)
 		WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
 
 		/*
-		 * Create temporary replication slot if no slot name is configured or
-		 * the slot from the previous run was temporary, unless
-		 * wal_receiver_create_temp_slot is disabled.  We also need to handle
-		 * the case where the previous run used a temporary slot but
-		 * wal_receiver_create_temp_slot was changed in the meantime.  In that
-		 * case, we delete the old slot name in shared memory.  (This would
+		 * Create temporary replication slot if requested.  In that
+		 * case, we update slot name in shared memory.  (This would
 		 * all be a bit easier if we just didn't copy the slot name into
 		 * shared memory, since we won't need it again later, but then we
 		 * can't see the slot name in the stats views.)
 		 */
-		if (slotname[0] == '\0' || is_temp_slot)
+		if (is_temp_slot)
 		{
-			bool		changed = false;
+			snprintf(slotname, sizeof(slotname),
+					 "pg_walreceiver_%lld",
+					 (long long int) walrcv_get_backend_pid(wrconn));
 
-			if (wal_receiver_create_temp_slot)
-			{
-				snprintf(slotname, sizeof(slotname),
-						 "pg_walreceiver_%lld",
-						 (long long int) walrcv_get_backend_pid(wrconn));
-
-				walrcv_create_slot(wrconn, slotname, true, 0, NULL);
-				changed = true;
-			}
-			else if (slotname[0] != '\0')
-			{
-				slotname[0] = '\0';
-				changed = true;
-			}
+			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
-			if (changed)
-			{
-				SpinLockAcquire(&walrcv->mutex);
-				strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
-				walrcv->is_temp_slot = wal_receiver_create_temp_slot;
-				SpinLockRelease(&walrcv->mutex);
-			}
+			SpinLockAcquire(&walrcv->mutex);
+			strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+			SpinLockRelease(&walrcv->mutex);
 		}
 
 		/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 89c903e45a..a36bc83d2c 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -248,10 +248,16 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	if (slotname != NULL)
+	if (slotname != NULL && slotname[0] != '\0')
+	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+		walrcv->is_temp_slot = false;
+	}
 	else
+	{
 		walrcv->slotname[0] = '\0';
+		walrcv->is_temp_slot = wal_receiver_create_temp_slot;
+	}
 
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 9f179a9129..c4b36eb2ad 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1994,7 +1994,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index e1048c0047..4454407b7c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -322,6 +322,7 @@
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
 #wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
+					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 98b033fc20..12362421d7 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..9d25a7f91b 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
 #include "utils/tuplestore.h"
 
 /* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
 extern int	wal_receiver_status_interval;
 extern int	wal_receiver_timeout;
 extern bool hot_standby_feedback;

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 2e2af9e96e..7887391bbb 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4005,9 +4005,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4022,9 +4028,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
@@ -4142,7 +4152,11 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
         The default is on.  The only reason to turn this off would be if the
         remote instance is currently out of available replication slots.  This
-        parameter can only be set at server start.
+        parameter can only be set in the <filename>postgresql.conf</filename>
+        file or on the server command line.
+       </para>
+       <para>
+        The WAL receiver is restarted after an update of <varname>wal_receiver_create_temp_slot</varname>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 408b9b489a..c24b93332e 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -803,6 +803,12 @@ static XLogSource readSource = 0;	/* XLOG_FROM_* code */
 static XLogSource currentSource = 0;	/* XLOG_FROM_* code */
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11831,6 +11837,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		int			oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11864,54 +11871,13 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
 					 * and move on to the next state.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12057,7 +12023,69 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * shutdown WAL receiver if restart is requested.
+					 */
+					if (!startWalReceiver && pendingWalRcvRestart)
+					{
+						if (WalRcvRunning())
+							ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12185,6 +12213,61 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured. We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = (tempSlot != wal_receiver_create_temp_slot);
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if ((conninfoChanged || slotnameChanged || tempSlotChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && strcmp(PrimaryConnInfo, "") == 0)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be shut down due to change of %s",
+							"primary_conninfo")));
+		else if (conninfoChanged && (slotnameChanged || tempSlotChanged))
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s and %s",
+							"primary_conninfo",
+							slotnameChanged ? "primary_slot_name" : "wal_receiver_create_temp_slot")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo"
+							: (slotnameChanged ? "primary_slot_name" : "wal_receiver_create_temp_slot"))));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index c2250d7d4e..c396fdae9a 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -101,12 +101,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 264b544194..f0651aade1 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -666,7 +666,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f20f572a62..8dd78fdd35 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1994,7 +1994,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
@@ -3643,7 +3643,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3654,7 +3654,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 4454407b7c..3dae3e9f3c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
@@ -322,7 +320,6 @@
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
 #wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
-					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 12362421d7..94009eb7be 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index d09ebe65a3..52585a1014 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 34;
+use Test::More tests => 35;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -345,6 +347,24 @@ is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
 
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");
+
 # Test physical slot advancing and its durability.  Create a new slot on
 # the primary, not used by any of the standbys. This reserves WAL at creation.
 my $phys_slot = 'phys_slot';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index c1128f89ec..2e2af9e96e 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4142,9 +4142,7 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
         The default is on.  The only reason to turn this off would be if the
         remote instance is currently out of available replication slots.  This
-        parameter can only be set in the <filename>postgresql.conf</filename>
-        file or on the server command line.  Changes only take effect when the
-        WAL receiver process starts a new connection.
+        parameter can only be set at server start.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 3813eadfb4..408b9b489a 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -283,6 +283,7 @@ bool		StandbyModeRequested = false;
 char	   *PrimaryConnInfo = NULL;
 char	   *PrimarySlotName = NULL;
 char	   *PromoteTriggerFile = NULL;
+bool		wal_receiver_create_temp_slot = true;
 
 /* are we currently in standby mode? */
 bool		StandbyMode = false;
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a5e85d32f3..264b544194 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -73,7 +73,6 @@
 
 
 /* GUC variables */
-bool		wal_receiver_create_temp_slot;
 int			wal_receiver_status_interval;
 int			wal_receiver_timeout;
 bool		hot_standby_feedback;
@@ -349,42 +348,23 @@ WalReceiverMain(void)
 		WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
 
 		/*
-		 * Create temporary replication slot if no slot name is configured or
-		 * the slot from the previous run was temporary, unless
-		 * wal_receiver_create_temp_slot is disabled.  We also need to handle
-		 * the case where the previous run used a temporary slot but
-		 * wal_receiver_create_temp_slot was changed in the meantime.  In that
-		 * case, we delete the old slot name in shared memory.  (This would
+		 * Create temporary replication slot if requested.  In that
+		 * case, we update slot name in shared memory.  (This would
 		 * all be a bit easier if we just didn't copy the slot name into
 		 * shared memory, since we won't need it again later, but then we
 		 * can't see the slot name in the stats views.)
 		 */
-		if (slotname[0] == '\0' || is_temp_slot)
+		if (is_temp_slot)
 		{
-			bool		changed = false;
+			snprintf(slotname, sizeof(slotname),
+					 "pg_walreceiver_%lld",
+					 (long long int) walrcv_get_backend_pid(wrconn));
 
-			if (wal_receiver_create_temp_slot)
-			{
-				snprintf(slotname, sizeof(slotname),
-						 "pg_walreceiver_%lld",
-						 (long long int) walrcv_get_backend_pid(wrconn));
-
-				walrcv_create_slot(wrconn, slotname, true, 0, NULL);
-				changed = true;
-			}
-			else if (slotname[0] != '\0')
-			{
-				slotname[0] = '\0';
-				changed = true;
-			}
+			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
-			if (changed)
-			{
-				SpinLockAcquire(&walrcv->mutex);
-				strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
-				walrcv->is_temp_slot = wal_receiver_create_temp_slot;
-				SpinLockRelease(&walrcv->mutex);
-			}
+			SpinLockAcquire(&walrcv->mutex);
+			strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+			SpinLockRelease(&walrcv->mutex);
 		}
 
 		/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 89c903e45a..a36bc83d2c 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -248,10 +248,16 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	if (slotname != NULL)
+	if (slotname != NULL && slotname[0] != '\0')
+	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+		walrcv->is_temp_slot = false;
+	}
 	else
+	{
 		walrcv->slotname[0] = '\0';
+		walrcv->is_temp_slot = wal_receiver_create_temp_slot;
+	}
 
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a16fe8cd5b..f20f572a62 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1994,7 +1994,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index e1048c0047..4454407b7c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -322,6 +322,7 @@
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
 #wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
+					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 98b033fc20..12362421d7 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..9d25a7f91b 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
 #include "utils/tuplestore.h"
 
 /* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
 extern int	wal_receiver_status_interval;
 extern int	wal_receiver_timeout;
 extern bool hot_standby_feedback;

diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 98b033fc20..12362421d7 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..cf3e43128c 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
 #include "utils/tuplestore.h"
 
 /* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
 extern int	wal_receiver_status_interval;
 extern int	wal_receiver_timeout;
 extern bool hot_standby_feedback;
@@ -321,7 +320,8 @@ extern void ShutdownWalRcv(void);
 extern bool WalRcvStreaming(void);
 extern bool WalRcvRunning(void);
 extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
-								 const char *conninfo, const char *slotname);
+								 const char *conninfo, const char *slotname,
+								 bool create_temp_slot);
 extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
 extern int	GetReplicationApplyDelay(void);
 extern int	GetReplicationTransferLatency(void);
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 3813eadfb4..e0f3ed5c2a 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -283,6 +283,7 @@ bool		StandbyModeRequested = false;
 char	   *PrimaryConnInfo = NULL;
 char	   *PrimarySlotName = NULL;
 char	   *PromoteTriggerFile = NULL;
+bool		wal_receiver_create_temp_slot = false;
 
 /* are we currently in standby mode? */
 bool		StandbyMode = false;
@@ -11901,7 +11902,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						}
 						curFileTLI = tli;
 						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
+											 PrimarySlotName, wal_receiver_create_temp_slot);
 						receivedUpto = 0;
 					}
 
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 2ab15c3cbb..ff45482faa 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -15,6 +15,12 @@
  * WalRcv->receivedUpto variable in shared memory, to inform the startup
  * process of how far it can proceed with XLOG replay.
  *
+ * WAL receivers cannot load directly GUC parameters used when establishing
+ * their connection to the primary, and rely on parameter values passed down
+ * by the startup process when WAL streaming is requested.  This applies
+ * to for example the replication slot creation and the connection string to
+ * use for the connection with the primary.
+ *
  * If the primary server ends streaming, but doesn't disconnect, walreceiver
  * goes into "waiting" mode, and waits for the startup process to give new
  * instructions. The startup process will treat that the same as
@@ -73,7 +79,6 @@
 
 
 /* GUC variables */
-bool		wal_receiver_create_temp_slot;
 int			wal_receiver_status_interval;
 int			wal_receiver_timeout;
 bool		hot_standby_feedback;
@@ -348,42 +353,23 @@ WalReceiverMain(void)
 		WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
 
 		/*
-		 * Create temporary replication slot if no slot name is configured or
-		 * the slot from the previous run was temporary, unless
-		 * wal_receiver_create_temp_slot is disabled.  We also need to handle
-		 * the case where the previous run used a temporary slot but
-		 * wal_receiver_create_temp_slot was changed in the meantime.  In that
-		 * case, we delete the old slot name in shared memory.  (This would
+		 * Create temporary replication slot if requested.  In that
+		 * case, we update slot name in shared memory.  (This would
 		 * all be a bit easier if we just didn't copy the slot name into
 		 * shared memory, since we won't need it again later, but then we
 		 * can't see the slot name in the stats views.)
 		 */
-		if (slotname[0] == '\0' || is_temp_slot)
+		if (is_temp_slot)
 		{
-			bool		changed = false;
+			snprintf(slotname, sizeof(slotname),
+					 "pg_walreceiver_%lld",
+					 (long long int) walrcv_get_backend_pid(wrconn));
 
-			if (wal_receiver_create_temp_slot)
-			{
-				snprintf(slotname, sizeof(slotname),
-						 "pg_walreceiver_%lld",
-						 (long long int) walrcv_get_backend_pid(wrconn));
+			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
-				walrcv_create_slot(wrconn, slotname, true, 0, NULL);
-				changed = true;
-			}
-			else if (slotname[0] != '\0')
-			{
-				slotname[0] = '\0';
-				changed = true;
-			}
-
-			if (changed)
-			{
-				SpinLockAcquire(&walrcv->mutex);
-				strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
-				walrcv->is_temp_slot = wal_receiver_create_temp_slot;
-				SpinLockRelease(&walrcv->mutex);
-			}
+			SpinLockAcquire(&walrcv->mutex);
+			strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+			SpinLockRelease(&walrcv->mutex);
 		}
 
 		/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 89c903e45a..821680a857 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -215,13 +215,19 @@ ShutdownWalRcv(void)
 /*
  * Request postmaster to start walreceiver.
  *
- * recptr indicates the position where streaming should begin, conninfo
- * is a libpq connection string to use, and slotname is, optionally, the name
- * of a replication slot to acquire.
+ * "recptr" indicates the position where streaming should begin.  "conninfo"
+ * is a libpq connection string to use.  "slotname" is, optionally, the name
+ * of a replication slot to acquire.  "create_temp_slot" indicates to create
+ * a temporary slot when no "slotname" is given.
+ *
+ * WAL receivers do not directly load GUC parameters used for the connection
+ * to the primary, and rely on the values passed down by the caller of this
+ * routine instead.  Hence, the addition of any new parameters should happen
+ * through this code path.
  */
 void
 RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
-					 const char *slotname)
+					 const char *slotname, bool create_temp_slot)
 {
 	WalRcvData *walrcv = WalRcv;
 	bool		launch = false;
@@ -248,10 +254,22 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
+	/*
+	 * Use configured replication slot if present, and ignore the value
+	 * of create_temp_slot as the slot name should be persistent.  Otherwise,
+	 * use create_temp_slot to determine whether this WAL receiver should
+	 * create a temporary slot by itself and use it, or not.
+	 */
 	if (slotname != NULL)
+	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+		walrcv->is_temp_slot = false;
+	}
 	else
+	{
 		walrcv->slotname[0] = '\0';
+		walrcv->is_temp_slot = create_temp_slot;
+	}
 
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 8228e1f390..ec9cd3696c 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2029,11 +2029,11 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
-		true,
+		false,
 		NULL, NULL, NULL
 	},
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index e1048c0047..1dd2a86567 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -321,7 +321,9 @@
 #max_standby_streaming_delay = 30s	# max delay before canceling queries
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
+#wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
+					# is not set.
+					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index c1128f89ec..683d87c491 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4140,11 +4140,7 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is on.  The only reason to turn this off would be if the
-        remote instance is currently out of available replication slots.  This
-        parameter can only be set in the <filename>postgresql.conf</filename>
-        file or on the server command line.  Changes only take effect when the
-        WAL receiver process starts a new connection.
+        The default is off.  This parameter can only be set at server start.
        </para>
       </listitem>
      </varlistentry>

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 8b742c83c5..f1d2a77043 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4025,9 +4025,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4042,9 +4048,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 483fedb218..e1f3e905bb 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -808,6 +808,12 @@ static XLogSource readSource = XLOG_FROM_ANY;
 static XLogSource currentSource = XLOG_FROM_ANY;
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11881,6 +11887,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		XLogSource	oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11914,54 +11921,13 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName, wal_receiver_create_temp_slot);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
 					 * and move on to the next state.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12113,7 +12079,69 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * shutdown WAL receiver if restart is requested.
+					 */
+					if (!startWalReceiver && pendingWalRcvRestart)
+					{
+						if (WalRcvRunning())
+							ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName, wal_receiver_create_temp_slot);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12241,6 +12269,50 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && strcmp(PrimaryConnInfo, "") == 0)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be shut down due to change of %s",
+							"primary_conninfo")));
+		else if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s and %s",
+							"primary_conninfo", "primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index c2250d7d4e..c396fdae9a 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -101,12 +101,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 779d19f1c1..0fd9886458 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -671,7 +671,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 80b6801c82..8d9bdc0eaf 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3697,7 +3697,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3708,7 +3708,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f2e55d1bd3..31096725fd 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 12362421d7..94009eb7be 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index d09ebe65a3..52585a1014 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 34;
+use Test::More tests => 35;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -345,6 +347,24 @@ is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
 
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");
+
 # Test physical slot advancing and its durability.  Create a new slot on
 # the primary, not used by any of the standbys. This reserves WAL at creation.
 my $phys_slot = 'phys_slot';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index f1d2a77043..eb6b3fb876 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4170,7 +4170,11 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is off.  This parameter can only be set at server start.
+        The default is off.  This parameter can only be set in the 
+        <filename>postgresql.conf</filename> file or on the server command line.
+       </para>
+       <para>
+        The WAL receiver is restarted after an update of <varname>wal_receiver_create_temp_slot</varname>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index e1f3e905bb..47d69d92d2 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -12278,8 +12278,10 @@ ProcessStartupSigHup(void)
 {
 	char	   *conninfo = pstrdup(PrimaryConnInfo);
 	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
 	bool		conninfoChanged;
 	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
 
 	ProcessConfigFile(PGC_SIGHUP);
 
@@ -12289,10 +12291,17 @@ ProcessStartupSigHup(void)
 	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
 	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
 
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured. We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = (tempSlot != wal_receiver_create_temp_slot);
+
 	pfree(conninfo);
 	pfree(slotname);
 
-	if ((conninfoChanged || slotnameChanged) &&
+	if ((conninfoChanged || slotnameChanged || tempSlotChanged) &&
 		currentSource == XLOG_FROM_STREAM
 		&& WalRcvRunning())
 	{
@@ -12300,14 +12309,16 @@ ProcessStartupSigHup(void)
 			ereport(LOG,
 					(errmsg("The WAL receiver is going to be shut down due to change of %s",
 							"primary_conninfo")));
-		else if (conninfoChanged && slotnameChanged)
+		else if (conninfoChanged && (slotnameChanged || tempSlotChanged))
 			ereport(LOG,
 					(errmsg("The WAL receiver is going to be restarted due to change of %s and %s",
-							"primary_conninfo", "primary_slot_name")));
+							"primary_conninfo",
+							slotnameChanged ? "primary_slot_name" : "wal_receiver_create_temp_slot")));
 		else
 			ereport(LOG,
 					(errmsg("The WAL receiver is going to be restarted due to change of %s",
-							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+							conninfoChanged ? "primary_conninfo"
+							: (slotnameChanged ? "primary_slot_name" : "wal_receiver_create_temp_slot"))));
 
 		pendingWalRcvRestart = true;
 	}
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 8d9bdc0eaf..a3650518c4 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2030,7 +2030,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 31096725fd..f01e43b818 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -321,7 +321,6 @@
 					# -1 allows indefinite delay
 #wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
 					# is not set.
-					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 8b742c83c5..f1d2a77043 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4025,9 +4025,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4042,9 +4048,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 483fedb218..e1f3e905bb 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -808,6 +808,12 @@ static XLogSource readSource = XLOG_FROM_ANY;
 static XLogSource currentSource = XLOG_FROM_ANY;
 static bool lastSourceFailed = false;
 
+/*
+ * Need for restart running WalReceiver due the configuration change.
+ * Suitable only for XLOG_FROM_STREAM source
+ */
+static bool pendingWalRcvRestart = false;
+
 typedef struct XLogPageReadPrivate
 {
 	int			emode;
@@ -11881,6 +11887,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		XLogSource	oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11914,54 +11921,13 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					if (!StandbyMode)
 						return false;
 
-					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName, wal_receiver_create_temp_slot);
-						receivedUpto = 0;
-					}
-
 					/*
 					 * Move to XLOG_FROM_STREAM state in either case. We'll
 					 * get immediate failure if we didn't launch walreceiver,
 					 * and move on to the next state.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12113,7 +12079,69 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * shutdown WAL receiver if restart is requested.
+					 */
+					if (!startWalReceiver && pendingWalRcvRestart)
+					{
+						if (WalRcvRunning())
+							ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName, wal_receiver_create_temp_slot);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12241,6 +12269,50 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+/*
+ * Re-read config file and plan to restart running walreceiver if
+ * connection settings was changed.
+ */
+void
+ProcessStartupSigHup(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	/*
+	 * We need restart walreceiver if replication settings was changed.
+	 */
+	conninfoChanged = (strcmp(conninfo, PrimaryConnInfo) != 0);
+	slotnameChanged = (strcmp(slotname, PrimarySlotName) != 0);
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if ((conninfoChanged || slotnameChanged) &&
+		currentSource == XLOG_FROM_STREAM
+		&& WalRcvRunning())
+	{
+		if (conninfoChanged && strcmp(PrimaryConnInfo, "") == 0)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be shut down due to change of %s",
+							"primary_conninfo")));
+		else if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s and %s",
+							"primary_conninfo", "primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index c2250d7d4e..c396fdae9a 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -101,12 +101,12 @@ void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		ProcessStartupSigHup();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 779d19f1c1..0fd9886458 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -671,7 +671,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 80b6801c82..8d9bdc0eaf 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3697,7 +3697,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3708,7 +3708,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f2e55d1bd3..31096725fd 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 12362421d7..94009eb7be 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -320,6 +320,7 @@ extern void SetWalWriterSleeping(bool sleeping);
 
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index d09ebe65a3..52585a1014 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 34;
+use Test::More tests => 35;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -345,6 +347,24 @@ is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
 
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");
+
 # Test physical slot advancing and its durability.  Create a new slot on
 # the primary, not used by any of the standbys. This reserves WAL at creation.
 my $phys_slot = 'phys_slot';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 672bf6f1ee..8b742c83c5 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4160,11 +4160,7 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is on.  The only reason to turn this off would be if the
-        remote instance is currently out of available replication slots.  This
-        parameter can only be set in the <filename>postgresql.conf</filename>
-        file or on the server command line.  Changes only take effect when the
-        WAL receiver process starts a new connection.
+        The default is off.  This parameter can only be set at server start.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index de2d4ee582..483fedb218 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -284,6 +284,7 @@ bool		StandbyModeRequested = false;
 char	   *PrimaryConnInfo = NULL;
 char	   *PrimarySlotName = NULL;
 char	   *PromoteTriggerFile = NULL;
+bool		wal_receiver_create_temp_slot = false;
 
 /* are we currently in standby mode? */
 bool		StandbyMode = false;
@@ -11951,7 +11952,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						}
 						curFileTLI = tli;
 						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
+											 PrimarySlotName, wal_receiver_create_temp_slot);
 						receivedUpto = 0;
 					}
 
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 25e0333c9e..779d19f1c1 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -15,6 +15,12 @@
  * WalRcv->receivedUpto variable in shared memory, to inform the startup
  * process of how far it can proceed with XLOG replay.
  *
+ * WAL receivers cannot load directly GUC parameters used when establishing
+ * their connection to the primary, and rely on parameter values passed down
+ * by the startup process when WAL streaming is requested.  This applies
+ * to for example the replication slot creation and the connection string to
+ * use for the connection with the primary.
+ *
  * If the primary server ends streaming, but doesn't disconnect, walreceiver
  * goes into "waiting" mode, and waits for the startup process to give new
  * instructions. The startup process will treat that the same as
@@ -74,7 +80,6 @@
 
 
 /* GUC variables */
-bool		wal_receiver_create_temp_slot;
 int			wal_receiver_status_interval;
 int			wal_receiver_timeout;
 bool		hot_standby_feedback;
@@ -349,42 +354,23 @@ WalReceiverMain(void)
 		WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
 
 		/*
-		 * Create temporary replication slot if no slot name is configured or
-		 * the slot from the previous run was temporary, unless
-		 * wal_receiver_create_temp_slot is disabled.  We also need to handle
-		 * the case where the previous run used a temporary slot but
-		 * wal_receiver_create_temp_slot was changed in the meantime.  In that
-		 * case, we delete the old slot name in shared memory.  (This would
+		 * Create temporary replication slot if requested.  In that
+		 * case, we update slot name in shared memory.  (This would
 		 * all be a bit easier if we just didn't copy the slot name into
 		 * shared memory, since we won't need it again later, but then we
 		 * can't see the slot name in the stats views.)
 		 */
-		if (slotname[0] == '\0' || is_temp_slot)
+		if (is_temp_slot)
 		{
-			bool		changed = false;
+			snprintf(slotname, sizeof(slotname),
+					 "pg_walreceiver_%lld",
+					 (long long int) walrcv_get_backend_pid(wrconn));
 
-			if (wal_receiver_create_temp_slot)
-			{
-				snprintf(slotname, sizeof(slotname),
-						 "pg_walreceiver_%lld",
-						 (long long int) walrcv_get_backend_pid(wrconn));
+			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
-				walrcv_create_slot(wrconn, slotname, true, 0, NULL);
-				changed = true;
-			}
-			else if (slotname[0] != '\0')
-			{
-				slotname[0] = '\0';
-				changed = true;
-			}
-
-			if (changed)
-			{
-				SpinLockAcquire(&walrcv->mutex);
-				strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
-				walrcv->is_temp_slot = wal_receiver_create_temp_slot;
-				SpinLockRelease(&walrcv->mutex);
-			}
+			SpinLockAcquire(&walrcv->mutex);
+			strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+			SpinLockRelease(&walrcv->mutex);
 		}
 
 		/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 89c903e45a..21d1823607 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -215,13 +215,19 @@ ShutdownWalRcv(void)
 /*
  * Request postmaster to start walreceiver.
  *
- * recptr indicates the position where streaming should begin, conninfo
- * is a libpq connection string to use, and slotname is, optionally, the name
- * of a replication slot to acquire.
+ * "recptr" indicates the position where streaming should begin.  "conninfo"
+ * is a libpq connection string to use.  "slotname" is, optionally, the name
+ * of a replication slot to acquire.  "create_temp_slot" indicates to create
+ * a temporary slot when no "slotname" is given.
+ *
+ * WAL receivers do not directly load GUC parameters used for the connection
+ * to the primary, and rely on the values passed down by the caller of this
+ * routine instead.  Hence, the addition of any new parameters should happen
+ * through this code path.
  */
 void
 RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
-					 const char *slotname)
+					 const char *slotname, bool create_temp_slot)
 {
 	WalRcvData *walrcv = WalRcv;
 	bool		launch = false;
@@ -248,10 +254,22 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	if (slotname != NULL)
+	/*
+	 * Use configured replication slot if present, and ignore the value
+	 * of create_temp_slot as the slot name should be persistent.  Otherwise,
+	 * use create_temp_slot to determine whether this WAL receiver should
+	 * create a temporary slot by itself and use it, or not.
+	 */
+	if (slotname != NULL && slotname[0] != '\0')
+	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+		walrcv->is_temp_slot = false;
+	}
 	else
+	{
 		walrcv->slotname[0] = '\0';
+		walrcv->is_temp_slot = create_temp_slot;
+	}
 
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 68082315ac..80b6801c82 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2030,11 +2030,11 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
-		true,
+		false,
 		NULL, NULL, NULL
 	},
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index aa44f0c9bf..f2e55d1bd3 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -321,7 +321,9 @@
 #max_standby_streaming_delay = 30s	# max delay before canceling queries
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
+#wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
+					# is not set.
+					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 98b033fc20..12362421d7 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..cf3e43128c 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
 #include "utils/tuplestore.h"
 
 /* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
 extern int	wal_receiver_status_interval;
 extern int	wal_receiver_timeout;
 extern bool hot_standby_feedback;
@@ -321,7 +320,8 @@ extern void ShutdownWalRcv(void);
 extern bool WalRcvStreaming(void);
 extern bool WalRcvRunning(void);
 extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
-								 const char *conninfo, const char *slotname);
+								 const char *conninfo, const char *slotname,
+								 bool create_temp_slot);
 extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
 extern int	GetReplicationApplyDelay(void);
 extern int	GetReplicationTransferLatency(void);

From 0bd43454e2981d9551b12424902d537674d48e31 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Wed, 25 Mar 2020 20:48:44 -0300
Subject: [PATCH v10 1/3] Set wal_receiver_create_temp_slot PGC_POSTMASTER

and off by default
---
 doc/src/sgml/config.sgml                      |  6 +--
 src/backend/access/transam/xlog.c             |  3 +-
 src/backend/replication/walreceiver.c         | 46 +++++++------------
 src/backend/replication/walreceiverfuncs.c    | 28 +++++++++--
 src/backend/utils/misc/guc.c                  |  4 +-
 src/backend/utils/misc/postgresql.conf.sample |  4 +-
 src/include/access/xlog.h                     |  1 +
 src/include/replication/walreceiver.h         |  4 +-
 8 files changed, 50 insertions(+), 46 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 355b408b0a..b5de6c3237 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4163,11 +4163,7 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is on.  The only reason to turn this off would be if the
-        remote instance is currently out of available replication slots.  This
-        parameter can only be set in the <filename>postgresql.conf</filename>
-        file or on the server command line.  Changes only take effect when the
-        WAL receiver process starts a new connection.
+        The default is off.  This parameter can only be set at server start.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7621fc05e2..19df1d5a80 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -290,6 +290,7 @@ bool		StandbyModeRequested = false;
 char	   *PrimaryConnInfo = NULL;
 char	   *PrimarySlotName = NULL;
 char	   *PromoteTriggerFile = NULL;
+bool		wal_receiver_create_temp_slot = false;
 
 /* are we currently in standby mode? */
 bool		StandbyMode = false;
@@ -11975,7 +11976,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						}
 						curFileTLI = tli;
 						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
+											 PrimarySlotName, wal_receiver_create_temp_slot);
 						receivedUpto = 0;
 					}
 
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 25e0333c9e..779d19f1c1 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -15,6 +15,12 @@
  * WalRcv->receivedUpto variable in shared memory, to inform the startup
  * process of how far it can proceed with XLOG replay.
  *
+ * WAL receivers cannot load directly GUC parameters used when establishing
+ * their connection to the primary, and rely on parameter values passed down
+ * by the startup process when WAL streaming is requested.  This applies
+ * to for example the replication slot creation and the connection string to
+ * use for the connection with the primary.
+ *
  * If the primary server ends streaming, but doesn't disconnect, walreceiver
  * goes into "waiting" mode, and waits for the startup process to give new
  * instructions. The startup process will treat that the same as
@@ -74,7 +80,6 @@
 
 
 /* GUC variables */
-bool		wal_receiver_create_temp_slot;
 int			wal_receiver_status_interval;
 int			wal_receiver_timeout;
 bool		hot_standby_feedback;
@@ -349,42 +354,23 @@ WalReceiverMain(void)
 		WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
 
 		/*
-		 * Create temporary replication slot if no slot name is configured or
-		 * the slot from the previous run was temporary, unless
-		 * wal_receiver_create_temp_slot is disabled.  We also need to handle
-		 * the case where the previous run used a temporary slot but
-		 * wal_receiver_create_temp_slot was changed in the meantime.  In that
-		 * case, we delete the old slot name in shared memory.  (This would
+		 * Create temporary replication slot if requested.  In that
+		 * case, we update slot name in shared memory.  (This would
 		 * all be a bit easier if we just didn't copy the slot name into
 		 * shared memory, since we won't need it again later, but then we
 		 * can't see the slot name in the stats views.)
 		 */
-		if (slotname[0] == '\0' || is_temp_slot)
+		if (is_temp_slot)
 		{
-			bool		changed = false;
+			snprintf(slotname, sizeof(slotname),
+					 "pg_walreceiver_%lld",
+					 (long long int) walrcv_get_backend_pid(wrconn));
 
-			if (wal_receiver_create_temp_slot)
-			{
-				snprintf(slotname, sizeof(slotname),
-						 "pg_walreceiver_%lld",
-						 (long long int) walrcv_get_backend_pid(wrconn));
+			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
-				walrcv_create_slot(wrconn, slotname, true, 0, NULL);
-				changed = true;
-			}
-			else if (slotname[0] != '\0')
-			{
-				slotname[0] = '\0';
-				changed = true;
-			}
-
-			if (changed)
-			{
-				SpinLockAcquire(&walrcv->mutex);
-				strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
-				walrcv->is_temp_slot = wal_receiver_create_temp_slot;
-				SpinLockRelease(&walrcv->mutex);
-			}
+			SpinLockAcquire(&walrcv->mutex);
+			strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+			SpinLockRelease(&walrcv->mutex);
 		}
 
 		/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 89c903e45a..21d1823607 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -215,13 +215,19 @@ ShutdownWalRcv(void)
 /*
  * Request postmaster to start walreceiver.
  *
- * recptr indicates the position where streaming should begin, conninfo
- * is a libpq connection string to use, and slotname is, optionally, the name
- * of a replication slot to acquire.
+ * "recptr" indicates the position where streaming should begin.  "conninfo"
+ * is a libpq connection string to use.  "slotname" is, optionally, the name
+ * of a replication slot to acquire.  "create_temp_slot" indicates to create
+ * a temporary slot when no "slotname" is given.
+ *
+ * WAL receivers do not directly load GUC parameters used for the connection
+ * to the primary, and rely on the values passed down by the caller of this
+ * routine instead.  Hence, the addition of any new parameters should happen
+ * through this code path.
  */
 void
 RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
-					 const char *slotname)
+					 const char *slotname, bool create_temp_slot)
 {
 	WalRcvData *walrcv = WalRcv;
 	bool		launch = false;
@@ -248,10 +254,22 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	if (slotname != NULL)
+	/*
+	 * Use configured replication slot if present, and ignore the value
+	 * of create_temp_slot as the slot name should be persistent.  Otherwise,
+	 * use create_temp_slot to determine whether this WAL receiver should
+	 * create a temporary slot by itself and use it, or not.
+	 */
+	if (slotname != NULL && slotname[0] != '\0')
+	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+		walrcv->is_temp_slot = false;
+	}
 	else
+	{
 		walrcv->slotname[0] = '\0';
+		walrcv->is_temp_slot = create_temp_slot;
+	}
 
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index af876d1f01..2c3cbbaa68 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2050,11 +2050,11 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
-		true,
+		false,
 		NULL, NULL, NULL
 	},
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index aa44f0c9bf..f2e55d1bd3 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -321,7 +321,9 @@
 #max_standby_streaming_delay = 30s	# max delay before canceling queries
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
+#wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
+					# is not set.
+					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 331497bcfb..a4485efc00 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..cf3e43128c 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
 #include "utils/tuplestore.h"
 
 /* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
 extern int	wal_receiver_status_interval;
 extern int	wal_receiver_timeout;
 extern bool hot_standby_feedback;
@@ -321,7 +320,8 @@ extern void ShutdownWalRcv(void);
 extern bool WalRcvStreaming(void);
 extern bool WalRcvRunning(void);
 extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
-								 const char *conninfo, const char *slotname);
+								 const char *conninfo, const char *slotname,
+								 bool create_temp_slot);
 extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
 extern int	GetReplicationApplyDelay(void);
 extern int	GetReplicationTransferLatency(void);
-- 
2.20.1

From 2aedb8e73c1b22c49763d09559f5489bbd2e07b7 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Wed, 25 Mar 2020 20:48:56 -0300
Subject: [PATCH v10 2/3] Allow changing primary_conninfo and primary_slot_name
 in SIGHUP

---
 doc/src/sgml/config.sgml                      |  16 +-
 src/backend/access/transam/xlog.c             | 144 ++++++++++++------
 src/backend/access/transam/xlogreader.c       |   6 +-
 src/backend/postmaster/startup.c              |  30 +++-
 src/backend/replication/walreceiver.c         |   6 +-
 src/backend/utils/misc/guc.c                  |   4 +-
 src/backend/utils/misc/postgresql.conf.sample |   2 -
 src/include/access/xlog.h                     |   2 +
 src/test/recovery/t/001_stream_rep.pl         |  24 ++-
 9 files changed, 173 insertions(+), 61 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index b5de6c3237..4d17dafa7e 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4028,9 +4028,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4045,9 +4051,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 19df1d5a80..fab6187120 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -816,9 +816,13 @@ static XLogSource readSource = XLOG_FROM_ANY;
  * currently have a WAL file open. If lastSourceFailed is set, our last
  * attempt to read from currentSource failed, and we should try another source
  * next.
+ *
+ * pendingWalRcvRestart is set when a config change occurs that requires a
+ * walreceiver restart.  This is only valid in XLOG_FROM_STREAM state.
  */
 static XLogSource currentSource = XLOG_FROM_ANY;
 static bool lastSourceFailed = false;
+static bool pendingWalRcvRestart = false;
 
 typedef struct XLogPageReadPrivate
 {
@@ -11905,6 +11909,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		XLogSource	oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11939,53 +11944,11 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						return false;
 
 					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName, wal_receiver_create_temp_slot);
-						receivedUpto = 0;
-					}
-
-					/*
-					 * Move to XLOG_FROM_STREAM state in either case. We'll
-					 * get immediate failure if we didn't launch walreceiver,
-					 * and move on to the next state.
+					 * Move to XLOG_FROM_STREAM state, and set to start a
+					 * walreceiver if necessary.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12137,7 +12100,70 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * First, shutdown walreceiver if its restart has been
+					 * requested -- but no point if we're already slated for
+					 * starting it.
+					 */
+					if (pendingWalRcvRestart && !startWalReceiver)
+					{
+						ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName, wal_receiver_create_temp_slot);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12265,6 +12291,32 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+StartupRequestWalReceiverRestart(void)
+{
+	if (currentSource == XLOG_FROM_STREAM && WalRcvRunning())
+	{
+		ereport(LOG,
+				(errmsg("wal receiver process shutdown requested")));
+#if 0
+		if (conninfoChanged && strcmp(PrimaryConnInfo, "") == 0)
+			ereport(LOG,
+					(errmsg("shutting down walreceiver")
+							"primary_conninfo")));
+		else if (conninfoChanged && slotnameChanged)
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s and %s",
+							"primary_conninfo", "primary_slot_name")));
+		else
+			ereport(LOG,
+					(errmsg("The WAL receiver is going to be restarted due to change of %s",
+							conninfoChanged ? "primary_conninfo" : "primary_slot_name")));
+#endif
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index 32f02256ed..f3fea5132f 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -585,9 +585,9 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
 	/*
 	 * Data is not in our buffer.
 	 *
-	 * Every time we actually read the page, even if we looked at parts of it
-	 * before, we need to do verification as the read_page callback might now
-	 * be rereading data from a different source.
+	 * Every time we actually read the segment, even if we looked at parts of
+	 * it before, we need to do verification as the read_page callback might
+	 * now be rereading data from a different source.
 	 *
 	 * Whenever switching to a new WAL segment, we read the first page of the
 	 * file and validate its header, even if that's not where the target
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 8952676765..f35b5adf7d 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -96,17 +96,43 @@ StartupProcShutdownHandler(SIGNAL_ARGS)
 	errno = save_errno;
 }
 
+/*
+ * Re-read the config file.
+ *
+ * If one of the critical walreceiver options has changed, flag xlog.c
+ * to restart it.
+ */
+static void
+StartupRereadConfig(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
+	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if (conninfoChanged || slotnameChanged)
+		StartupRequestWalReceiverRestart();
+}
+
 /* Handle various signals that might be sent to the startup process */
 void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		StartupRereadConfig();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 779d19f1c1..0fd9886458 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -671,7 +671,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * We don't need handle changes of primary_conninfo or
+			 * primary_slotname here. Startup process will shutdown running
+			 * walreceiver in this case.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 2c3cbbaa68..2d149dfaa5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3717,7 +3717,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3728,7 +3728,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f2e55d1bd3..31096725fd 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index a4485efc00..997db214cc 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -319,8 +319,10 @@ extern bool CheckPromoteSignal(void);
 extern void WakeupRecovery(void);
 extern void SetWalWriterSleeping(bool sleeping);
 
+extern void StartupRequestWalReceiverRestart(void);
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index d09ebe65a3..52585a1014 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 34;
+use Test::More tests => 35;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -345,6 +347,24 @@ is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
 
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");
+
 # Test physical slot advancing and its durability.  Create a new slot on
 # the primary, not used by any of the standbys. This reserves WAL at creation.
 my $phys_slot = 'phys_slot';
-- 
2.20.1

From f5f20625b1f297cac177917c6e9b1f110ffea707 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Wed, 25 Mar 2020 20:54:27 -0300
Subject: [PATCH v10 3/3] Set wal_receiver_create_temp_slot as PGC_SIGHUP

.. using the new infrastructure
---
 doc/src/sgml/config.sgml                      |  6 +++++-
 src/backend/postmaster/startup.c              | 10 +++++++++-
 src/backend/utils/misc/guc.c                  |  2 +-
 src/backend/utils/misc/postgresql.conf.sample |  1 -
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 4d17dafa7e..c5160fe907 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4173,7 +4173,11 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is off.  This parameter can only be set at server start.
+        The default is off.  This parameter can only be set in the 
+        <filename>postgresql.conf</filename> file or on the server command line.
+       </para>
+       <para>
+        The WAL receiver is restarted after an update of <varname>wal_receiver_create_temp_slot</varname>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index f35b5adf7d..fd9ac35dac 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -107,18 +107,26 @@ StartupRereadConfig(void)
 {
 	char	   *conninfo = pstrdup(PrimaryConnInfo);
 	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
 	bool		conninfoChanged;
 	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
 
 	ProcessConfigFile(PGC_SIGHUP);
 
 	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
 	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
 
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured.  We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = tempSlot != wal_receiver_create_temp_slot;
 	pfree(conninfo);
 	pfree(slotname);
 
-	if (conninfoChanged || slotnameChanged)
+	if (conninfoChanged || slotnameChanged || tempSlotChanged)
 		StartupRequestWalReceiverRestart();
 }
 
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 2d149dfaa5..53665971f5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2050,7 +2050,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 31096725fd..f01e43b818 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -321,7 +321,6 @@
 					# -1 allows indefinite delay
 #wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
 					# is not set.
-					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
-- 
2.20.1

From f7a9717caa9dd73c00fb5e6a1dddb354ad78d09a Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Wed, 25 Mar 2020 20:48:56 -0300
Subject: [PATCH v11 1/3] Allow changing primary_conninfo and primary_slot_name
 in SIGHUP

---
 doc/src/sgml/config.sgml                      |  16 ++-
 src/backend/access/transam/xlog.c             | 130 +++++++++++-------
 src/backend/access/transam/xlogreader.c       |   6 +-
 src/backend/postmaster/startup.c              |  30 +++-
 src/backend/replication/walreceiver.c         |  12 +-
 src/backend/utils/misc/guc.c                  |   4 +-
 src/backend/utils/misc/postgresql.conf.sample |   2 -
 src/include/access/xlog.h                     |   2 +
 src/test/recovery/t/001_stream_rep.pl         |  24 +++-
 9 files changed, 165 insertions(+), 61 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 355b408b0a..1cf88e953d 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4028,9 +4028,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4045,9 +4051,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7621fc05e2..bbf8d4eee5 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -815,9 +815,13 @@ static XLogSource readSource = XLOG_FROM_ANY;
  * currently have a WAL file open. If lastSourceFailed is set, our last
  * attempt to read from currentSource failed, and we should try another source
  * next.
+ *
+ * pendingWalRcvRestart is set when a config change occurs that requires a
+ * walreceiver restart.  This is only valid in XLOG_FROM_STREAM state.
  */
 static XLogSource currentSource = XLOG_FROM_ANY;
 static bool lastSourceFailed = false;
+static bool pendingWalRcvRestart = false;
 
 typedef struct XLogPageReadPrivate
 {
@@ -11904,6 +11908,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		XLogSource	oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11938,53 +11943,11 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						return false;
 
 					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
-					/*
-					 * Move to XLOG_FROM_STREAM state in either case. We'll
-					 * get immediate failure if we didn't launch walreceiver,
-					 * and move on to the next state.
+					 * Move to XLOG_FROM_STREAM state, and set to start a
+					 * walreceiver if necessary.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12136,7 +12099,70 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * First, shutdown walreceiver if its restart has been
+					 * requested -- but no point if we're already slated for
+					 * starting it.
+					 */
+					if (pendingWalRcvRestart && !startWalReceiver)
+					{
+						ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12264,6 +12290,18 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+StartupRequestWalReceiverRestart(void)
+{
+	if (currentSource == XLOG_FROM_STREAM && WalRcvRunning())
+	{
+		ereport(LOG,
+				(errmsg("wal receiver process shutdown requested")));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index 32f02256ed..f3fea5132f 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -585,9 +585,9 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
 	/*
 	 * Data is not in our buffer.
 	 *
-	 * Every time we actually read the page, even if we looked at parts of it
-	 * before, we need to do verification as the read_page callback might now
-	 * be rereading data from a different source.
+	 * Every time we actually read the segment, even if we looked at parts of
+	 * it before, we need to do verification as the read_page callback might
+	 * now be rereading data from a different source.
 	 *
 	 * Whenever switching to a new WAL segment, we read the first page of the
 	 * file and validate its header, even if that's not where the target
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 8952676765..f35b5adf7d 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -96,17 +96,43 @@ StartupProcShutdownHandler(SIGNAL_ARGS)
 	errno = save_errno;
 }
 
+/*
+ * Re-read the config file.
+ *
+ * If one of the critical walreceiver options has changed, flag xlog.c
+ * to restart it.
+ */
+static void
+StartupRereadConfig(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
+	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if (conninfoChanged || slotnameChanged)
+		StartupRequestWalReceiverRestart();
+}
+
 /* Handle various signals that might be sent to the startup process */
 void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		StartupRereadConfig();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 25e0333c9e..b471a49d12 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -15,6 +15,12 @@
  * WalRcv->receivedUpto variable in shared memory, to inform the startup
  * process of how far it can proceed with XLOG replay.
  *
+ * A WAL receiver cannot directly load GUC parameters used when establishing
+ * its connection to the primary. Instead it relies on parameter values
+ * that are passed down by the startup process when streaming is requested.
+ * This applies, for example, to the replication slot and the connection
+ * string to be used for the connection with the primary.
+ *
  * If the primary server ends streaming, but doesn't disconnect, walreceiver
  * goes into "waiting" mode, and waits for the startup process to give new
  * instructions. The startup process will treat that the same as
@@ -685,7 +691,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * No need to handle changes in primary_conninfo or
+			 * primary_slotname here. Startup process will signal us in case
+			 * those change.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index af876d1f01..c0b2b75407 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3717,7 +3717,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3728,7 +3728,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index aa44f0c9bf..c4f2f881c9 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 331497bcfb..42c4df0262 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -318,8 +318,10 @@ extern bool CheckPromoteSignal(void);
 extern void WakeupRecovery(void);
 extern void SetWalWriterSleeping(bool sleeping);
 
+extern void StartupRequestWalReceiverRestart(void);
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index d09ebe65a3..52585a1014 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 34;
+use Test::More tests => 35;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -345,6 +347,24 @@ is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
 
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");
+
 # Test physical slot advancing and its durability.  Create a new slot on
 # the primary, not used by any of the standbys. This reserves WAL at creation.
 my $phys_slot = 'phys_slot';
-- 
2.20.1

From 14ac73a42247fdfc5d02a19ac1b9b13dc9efeccf Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Thu, 26 Mar 2020 21:04:42 -0300
Subject: [PATCH v11 2/3] Fix tests

---
 src/test/recovery/t/001_stream_rep.pl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 52585a1014..3408eaf551 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -22,6 +22,7 @@ $node_master->backup($backup_name);
 my $node_standby_1 = get_new_node('standby_1');
 $node_standby_1->init_from_backup($node_master, $backup_name,
 	has_streaming => 1);
+$node_standby_1->append_conf('postgresql.conf', "wal_receiver_create_temp_slot = false");
 $node_standby_1->start;
 
 # Take backup of standby 1 (not mandatory, but useful to check if
-- 
2.20.1

From 29acdc47bf6a805c9ed24cb20d6a8a01a7fe93fc Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Wed, 25 Mar 2020 20:48:44 -0300
Subject: [PATCH v11 3/3] Rework wal_receiver_create_temp_slot using new
 infrastructure

---
 doc/src/sgml/config.sgml                      | 10 ++---
 src/backend/access/transam/xlog.c             |  3 +-
 src/backend/postmaster/startup.c              | 10 ++++-
 src/backend/replication/walreceiver.c         | 40 +++++--------------
 src/backend/replication/walreceiverfuncs.c    | 28 ++++++++++---
 src/backend/utils/misc/guc.c                  |  2 +-
 src/backend/utils/misc/postgresql.conf.sample |  3 +-
 src/include/access/xlog.h                     |  1 +
 src/include/replication/walreceiver.h         |  4 +-
 9 files changed, 55 insertions(+), 46 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 1cf88e953d..c5160fe907 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4173,11 +4173,11 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is on.  The only reason to turn this off would be if the
-        remote instance is currently out of available replication slots.  This
-        parameter can only be set in the <filename>postgresql.conf</filename>
-        file or on the server command line.  Changes only take effect when the
-        WAL receiver process starts a new connection.
+        The default is off.  This parameter can only be set in the 
+        <filename>postgresql.conf</filename> file or on the server command line.
+       </para>
+       <para>
+        The WAL receiver is restarted after an update of <varname>wal_receiver_create_temp_slot</varname>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index bbf8d4eee5..2ecb319438 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -290,6 +290,7 @@ bool		StandbyModeRequested = false;
 char	   *PrimaryConnInfo = NULL;
 char	   *PrimarySlotName = NULL;
 char	   *PromoteTriggerFile = NULL;
+bool		wal_receiver_create_temp_slot = false;
 
 /* are we currently in standby mode? */
 bool		StandbyMode = false;
@@ -12157,7 +12158,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						}
 						curFileTLI = tli;
 						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
+											 PrimarySlotName, wal_receiver_create_temp_slot);
 						receivedUpto = 0;
 					}
 
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index f35b5adf7d..fd9ac35dac 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -107,18 +107,26 @@ StartupRereadConfig(void)
 {
 	char	   *conninfo = pstrdup(PrimaryConnInfo);
 	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
 	bool		conninfoChanged;
 	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
 
 	ProcessConfigFile(PGC_SIGHUP);
 
 	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
 	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
 
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured.  We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = tempSlot != wal_receiver_create_temp_slot;
 	pfree(conninfo);
 	pfree(slotname);
 
-	if (conninfoChanged || slotnameChanged)
+	if (conninfoChanged || slotnameChanged || tempSlotChanged)
 		StartupRequestWalReceiverRestart();
 }
 
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index b471a49d12..0aa0c52c49 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -80,7 +80,6 @@
 
 
 /* GUC variables */
-bool		wal_receiver_create_temp_slot;
 int			wal_receiver_status_interval;
 int			wal_receiver_timeout;
 bool		hot_standby_feedback;
@@ -355,42 +354,23 @@ WalReceiverMain(void)
 		WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
 
 		/*
-		 * Create temporary replication slot if no slot name is configured or
-		 * the slot from the previous run was temporary, unless
-		 * wal_receiver_create_temp_slot is disabled.  We also need to handle
-		 * the case where the previous run used a temporary slot but
-		 * wal_receiver_create_temp_slot was changed in the meantime.  In that
-		 * case, we delete the old slot name in shared memory.  (This would
+		 * Create temporary replication slot if requested.  In that
+		 * case, we update slot name in shared memory.  (This would
 		 * all be a bit easier if we just didn't copy the slot name into
 		 * shared memory, since we won't need it again later, but then we
 		 * can't see the slot name in the stats views.)
 		 */
-		if (slotname[0] == '\0' || is_temp_slot)
+		if (is_temp_slot)
 		{
-			bool		changed = false;
+			snprintf(slotname, sizeof(slotname),
+					 "pg_walreceiver_%lld",
+					 (long long int) walrcv_get_backend_pid(wrconn));
 
-			if (wal_receiver_create_temp_slot)
-			{
-				snprintf(slotname, sizeof(slotname),
-						 "pg_walreceiver_%lld",
-						 (long long int) walrcv_get_backend_pid(wrconn));
+			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
-				walrcv_create_slot(wrconn, slotname, true, 0, NULL);
-				changed = true;
-			}
-			else if (slotname[0] != '\0')
-			{
-				slotname[0] = '\0';
-				changed = true;
-			}
-
-			if (changed)
-			{
-				SpinLockAcquire(&walrcv->mutex);
-				strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
-				walrcv->is_temp_slot = wal_receiver_create_temp_slot;
-				SpinLockRelease(&walrcv->mutex);
-			}
+			SpinLockAcquire(&walrcv->mutex);
+			strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+			SpinLockRelease(&walrcv->mutex);
 		}
 
 		/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 89c903e45a..21d1823607 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -215,13 +215,19 @@ ShutdownWalRcv(void)
 /*
  * Request postmaster to start walreceiver.
  *
- * recptr indicates the position where streaming should begin, conninfo
- * is a libpq connection string to use, and slotname is, optionally, the name
- * of a replication slot to acquire.
+ * "recptr" indicates the position where streaming should begin.  "conninfo"
+ * is a libpq connection string to use.  "slotname" is, optionally, the name
+ * of a replication slot to acquire.  "create_temp_slot" indicates to create
+ * a temporary slot when no "slotname" is given.
+ *
+ * WAL receivers do not directly load GUC parameters used for the connection
+ * to the primary, and rely on the values passed down by the caller of this
+ * routine instead.  Hence, the addition of any new parameters should happen
+ * through this code path.
  */
 void
 RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
-					 const char *slotname)
+					 const char *slotname, bool create_temp_slot)
 {
 	WalRcvData *walrcv = WalRcv;
 	bool		launch = false;
@@ -248,10 +254,22 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	if (slotname != NULL)
+	/*
+	 * Use configured replication slot if present, and ignore the value
+	 * of create_temp_slot as the slot name should be persistent.  Otherwise,
+	 * use create_temp_slot to determine whether this WAL receiver should
+	 * create a temporary slot by itself and use it, or not.
+	 */
+	if (slotname != NULL && slotname[0] != '\0')
+	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+		walrcv->is_temp_slot = false;
+	}
 	else
+	{
 		walrcv->slotname[0] = '\0';
+		walrcv->is_temp_slot = create_temp_slot;
+	}
 
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c0b2b75407..53665971f5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2054,7 +2054,7 @@ static struct config_bool ConfigureNamesBool[] =
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
-		true,
+		false,
 		NULL, NULL, NULL
 	},
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index c4f2f881c9..f01e43b818 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -319,7 +319,8 @@
 #max_standby_streaming_delay = 30s	# max delay before canceling queries
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
+#wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
+					# is not set.
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 42c4df0262..997db214cc 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..cf3e43128c 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
 #include "utils/tuplestore.h"
 
 /* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
 extern int	wal_receiver_status_interval;
 extern int	wal_receiver_timeout;
 extern bool hot_standby_feedback;
@@ -321,7 +320,8 @@ extern void ShutdownWalRcv(void);
 extern bool WalRcvStreaming(void);
 extern bool WalRcvRunning(void);
 extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
-								 const char *conninfo, const char *slotname);
+								 const char *conninfo, const char *slotname,
+								 bool create_temp_slot);
 extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
 extern int	GetReplicationApplyDelay(void);
 extern int	GetReplicationTransferLatency(void);
-- 
2.20.1

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index c5160fe907..d18921725c 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4171,9 +4171,9 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
       <listitem>
        <para>
         Specifies whether a WAL receiver should create a temporary replication
-        slot on the remote instance when no permanent replication slot to use
-        has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is off.  This parameter can only be set in the 
+        slot on the remote instance. The slot will be created with the name
+        configured by <xref linkend="guc-primary-slot-name"/> setting, otherwise
+        with the generated name. The default is off.  This parameter can only be set in the 
         <filename>postgresql.conf</filename> file or on the server command line.
        </para>
        <para>
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 0aa0c52c49..af9b9d586c 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -362,9 +362,10 @@ WalReceiverMain(void)
 		 */
 		if (is_temp_slot)
 		{
-			snprintf(slotname, sizeof(slotname),
-					 "pg_walreceiver_%lld",
-					 (long long int) walrcv_get_backend_pid(wrconn));
+			if (slotname[0] == '\0')
+				snprintf(slotname, sizeof(slotname),
+						"pg_walreceiver_%lld",
+						(long long int) walrcv_get_backend_pid(wrconn));
 
 			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 21d1823607..28117883e1 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -218,7 +218,7 @@ ShutdownWalRcv(void)
  * "recptr" indicates the position where streaming should begin.  "conninfo"
  * is a libpq connection string to use.  "slotname" is, optionally, the name
  * of a replication slot to acquire.  "create_temp_slot" indicates to create
- * a temporary slot when no "slotname" is given.
+ * a temporary slot.
  *
  * WAL receivers do not directly load GUC parameters used for the connection
  * to the primary, and rely on the values passed down by the caller of this
@@ -254,23 +254,17 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	/*
-	 * Use configured replication slot if present, and ignore the value
-	 * of create_temp_slot as the slot name should be persistent.  Otherwise,
-	 * use create_temp_slot to determine whether this WAL receiver should
-	 * create a temporary slot by itself and use it, or not.
-	 */
 	if (slotname != NULL && slotname[0] != '\0')
 	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
-		walrcv->is_temp_slot = false;
 	}
 	else
 	{
 		walrcv->slotname[0] = '\0';
-		walrcv->is_temp_slot = create_temp_slot;
 	}
 
+	walrcv->is_temp_slot = create_temp_slot;
+
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
 		launch = true;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 53665971f5..51ef6987b5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2051,7 +2051,7 @@ static struct config_bool ConfigureNamesBool[] =
 
 	{
 		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
-			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
+			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot."),
 		},
 		&wal_receiver_create_temp_slot,
 		false,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f01e43b818..5308d602f4 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -319,8 +319,7 @@
 #max_standby_streaming_delay = 30s	# max delay before canceling queries
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
-					# is not set.
+#wal_receiver_create_temp_slot = off	# Create temp replication slot
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 1cf88e953d..c5160fe907 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4173,11 +4173,11 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is on.  The only reason to turn this off would be if the
-        remote instance is currently out of available replication slots.  This
-        parameter can only be set in the <filename>postgresql.conf</filename>
-        file or on the server command line.  Changes only take effect when the
-        WAL receiver process starts a new connection.
+        The default is off.  This parameter can only be set in the 
+        <filename>postgresql.conf</filename> file or on the server command line.
+       </para>
+       <para>
+        The WAL receiver is restarted after an update of <varname>wal_receiver_create_temp_slot</varname>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index bbf8d4eee5..2ecb319438 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -290,6 +290,7 @@ bool		StandbyModeRequested = false;
 char	   *PrimaryConnInfo = NULL;
 char	   *PrimarySlotName = NULL;
 char	   *PromoteTriggerFile = NULL;
+bool		wal_receiver_create_temp_slot = false;
 
 /* are we currently in standby mode? */
 bool		StandbyMode = false;
@@ -12157,7 +12158,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						}
 						curFileTLI = tli;
 						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
+											 PrimarySlotName, wal_receiver_create_temp_slot);
 						receivedUpto = 0;
 					}
 
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index f35b5adf7d..0dbf50934e 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -107,8 +107,10 @@ StartupRereadConfig(void)
 {
 	char	   *conninfo = pstrdup(PrimaryConnInfo);
 	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
 	bool		conninfoChanged;
 	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
 
 	ProcessConfigFile(PGC_SIGHUP);
 
@@ -118,7 +120,14 @@ StartupRereadConfig(void)
 	pfree(conninfo);
 	pfree(slotname);
 
-	if (conninfoChanged || slotnameChanged)
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured.  We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = tempSlot != wal_receiver_create_temp_slot;
+
+	if (conninfoChanged || slotnameChanged || tempSlotChanged)
 		StartupRequestWalReceiverRestart();
 }
 
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index d11c957b15..0aa0c52c49 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -15,6 +15,12 @@
  * WalRcv->receivedUpto variable in shared memory, to inform the startup
  * process of how far it can proceed with XLOG replay.
  *
+ * A WAL receiver cannot directly load GUC parameters used when establishing
+ * its connection to the primary. Instead it relies on parameter values
+ * that are passed down by the startup process when streaming is requested.
+ * This applies, for example, to the replication slot and the connection
+ * string to be used for the connection with the primary.
+ *
  * If the primary server ends streaming, but doesn't disconnect, walreceiver
  * goes into "waiting" mode, and waits for the startup process to give new
  * instructions. The startup process will treat that the same as
@@ -74,7 +80,6 @@
 
 
 /* GUC variables */
-bool		wal_receiver_create_temp_slot;
 int			wal_receiver_status_interval;
 int			wal_receiver_timeout;
 bool		hot_standby_feedback;
@@ -349,42 +354,23 @@ WalReceiverMain(void)
 		WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
 
 		/*
-		 * Create temporary replication slot if no slot name is configured or
-		 * the slot from the previous run was temporary, unless
-		 * wal_receiver_create_temp_slot is disabled.  We also need to handle
-		 * the case where the previous run used a temporary slot but
-		 * wal_receiver_create_temp_slot was changed in the meantime.  In that
-		 * case, we delete the old slot name in shared memory.  (This would
+		 * Create temporary replication slot if requested.  In that
+		 * case, we update slot name in shared memory.  (This would
 		 * all be a bit easier if we just didn't copy the slot name into
 		 * shared memory, since we won't need it again later, but then we
 		 * can't see the slot name in the stats views.)
 		 */
-		if (slotname[0] == '\0' || is_temp_slot)
+		if (is_temp_slot)
 		{
-			bool		changed = false;
+			snprintf(slotname, sizeof(slotname),
+					 "pg_walreceiver_%lld",
+					 (long long int) walrcv_get_backend_pid(wrconn));
 
-			if (wal_receiver_create_temp_slot)
-			{
-				snprintf(slotname, sizeof(slotname),
-						 "pg_walreceiver_%lld",
-						 (long long int) walrcv_get_backend_pid(wrconn));
+			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
-				walrcv_create_slot(wrconn, slotname, true, 0, NULL);
-				changed = true;
-			}
-			else if (slotname[0] != '\0')
-			{
-				slotname[0] = '\0';
-				changed = true;
-			}
-
-			if (changed)
-			{
-				SpinLockAcquire(&walrcv->mutex);
-				strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
-				walrcv->is_temp_slot = wal_receiver_create_temp_slot;
-				SpinLockRelease(&walrcv->mutex);
-			}
+			SpinLockAcquire(&walrcv->mutex);
+			strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
+			SpinLockRelease(&walrcv->mutex);
 		}
 
 		/*
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 6926a7b514..21d1823607 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -215,13 +215,19 @@ ShutdownWalRcv(void)
 /*
  * Request postmaster to start walreceiver.
  *
- * recptr indicates the position where streaming should begin, conninfo
- * is a libpq connection string to use, and slotname is, optionally, the name
- * of a replication slot to acquire.
+ * "recptr" indicates the position where streaming should begin.  "conninfo"
+ * is a libpq connection string to use.  "slotname" is, optionally, the name
+ * of a replication slot to acquire.  "create_temp_slot" indicates to create
+ * a temporary slot when no "slotname" is given.
+ *
+ * WAL receivers do not directly load GUC parameters used for the connection
+ * to the primary, and rely on the values passed down by the caller of this
+ * routine instead.  Hence, the addition of any new parameters should happen
+ * through this code path.
  */
 void
 RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
-					 const char *slotname)
+					 const char *slotname, bool create_temp_slot)
 {
 	WalRcvData *walrcv = WalRcv;
 	bool		launch = false;
@@ -248,15 +254,22 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	if (slotname != NULL)
+	/*
+	 * Use configured replication slot if present, and ignore the value
+	 * of create_temp_slot as the slot name should be persistent.  Otherwise,
+	 * use create_temp_slot to determine whether this WAL receiver should
+	 * create a temporary slot by itself and use it, or not.
+	 */
+	if (slotname != NULL && slotname[0] != '\0')
+	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
+		walrcv->is_temp_slot = false;
+	}
 	else
+	{
 		walrcv->slotname[0] = '\0';
-
-	/*
-	 * walreceiver will handle temporary slot by itself
-	 */
-	walrcv->is_temp_slot = false;
+		walrcv->is_temp_slot = create_temp_slot;
+	}
 
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c0b2b75407..53665971f5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2054,7 +2054,7 @@ static struct config_bool ConfigureNamesBool[] =
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
-		true,
+		false,
 		NULL, NULL, NULL
 	},
 
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index c4f2f881c9..f01e43b818 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -319,7 +319,8 @@
 #max_standby_streaming_delay = 30s	# max delay before canceling queries
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = on	# create temp slot if primary_slot_name not set
+#wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
+					# is not set.
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 42c4df0262..997db214cc 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -129,6 +129,7 @@ extern int	recoveryTargetAction;
 extern int	recovery_min_apply_delay;
 extern char *PrimaryConnInfo;
 extern char *PrimarySlotName;
+extern bool wal_receiver_create_temp_slot;
 
 /* indirectly set via GUC system */
 extern TransactionId recoveryTargetXid;
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index e08afc6548..cf3e43128c 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -23,7 +23,6 @@
 #include "utils/tuplestore.h"
 
 /* user-settable parameters */
-extern bool wal_receiver_create_temp_slot;
 extern int	wal_receiver_status_interval;
 extern int	wal_receiver_timeout;
 extern bool hot_standby_feedback;
@@ -321,7 +320,8 @@ extern void ShutdownWalRcv(void);
 extern bool WalRcvStreaming(void);
 extern bool WalRcvRunning(void);
 extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
-								 const char *conninfo, const char *slotname);
+								 const char *conninfo, const char *slotname,
+								 bool create_temp_slot);
 extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
 extern int	GetReplicationApplyDelay(void);
 extern int	GetReplicationTransferLatency(void);

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 355b408b0a..1cf88e953d 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4028,9 +4028,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4045,9 +4051,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 7621fc05e2..bbf8d4eee5 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -815,9 +815,13 @@ static XLogSource readSource = XLOG_FROM_ANY;
  * currently have a WAL file open. If lastSourceFailed is set, our last
  * attempt to read from currentSource failed, and we should try another source
  * next.
+ *
+ * pendingWalRcvRestart is set when a config change occurs that requires a
+ * walreceiver restart.  This is only valid in XLOG_FROM_STREAM state.
  */
 static XLogSource currentSource = XLOG_FROM_ANY;
 static bool lastSourceFailed = false;
+static bool pendingWalRcvRestart = false;
 
 typedef struct XLogPageReadPrivate
 {
@@ -11904,6 +11908,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		XLogSource	oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11938,53 +11943,11 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						return false;
 
 					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName);
-						receivedUpto = 0;
-					}
-
-					/*
-					 * Move to XLOG_FROM_STREAM state in either case. We'll
-					 * get immediate failure if we didn't launch walreceiver,
-					 * and move on to the next state.
+					 * Move to XLOG_FROM_STREAM state, and set to start a
+					 * walreceiver if necessary.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12136,7 +12099,70 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * First, shutdown walreceiver if its restart has been
+					 * requested -- but no point if we're already slated for
+					 * starting it.
+					 */
+					if (pendingWalRcvRestart && !startWalReceiver)
+					{
+						ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12264,6 +12290,18 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+StartupRequestWalReceiverRestart(void)
+{
+	if (currentSource == XLOG_FROM_STREAM && WalRcvRunning())
+	{
+		ereport(LOG,
+				(errmsg("wal receiver process shutdown requested")));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index 32f02256ed..f3fea5132f 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -585,9 +585,9 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
 	/*
 	 * Data is not in our buffer.
 	 *
-	 * Every time we actually read the page, even if we looked at parts of it
-	 * before, we need to do verification as the read_page callback might now
-	 * be rereading data from a different source.
+	 * Every time we actually read the segment, even if we looked at parts of
+	 * it before, we need to do verification as the read_page callback might
+	 * now be rereading data from a different source.
 	 *
 	 * Whenever switching to a new WAL segment, we read the first page of the
 	 * file and validate its header, even if that's not where the target
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 8952676765..f35b5adf7d 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -96,17 +96,43 @@ StartupProcShutdownHandler(SIGNAL_ARGS)
 	errno = save_errno;
 }
 
+/*
+ * Re-read the config file.
+ *
+ * If one of the critical walreceiver options has changed, flag xlog.c
+ * to restart it.
+ */
+static void
+StartupRereadConfig(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
+	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
+
+	pfree(conninfo);
+	pfree(slotname);
+
+	if (conninfoChanged || slotnameChanged)
+		StartupRequestWalReceiverRestart();
+}
+
 /* Handle various signals that might be sent to the startup process */
 void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		StartupRereadConfig();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 25e0333c9e..d11c957b15 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -685,7 +685,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * No need to handle changes in primary_conninfo or
+			 * primary_slotname here. Startup process will signal us in case
+			 * those change.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 89c903e45a..6926a7b514 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -253,6 +253,11 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->slotname[0] = '\0';
 
+	/*
+	 * walreceiver will handle temporary slot by itself
+	 */
+	walrcv->is_temp_slot = false;
+
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
 		launch = true;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index af876d1f01..c0b2b75407 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3717,7 +3717,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3728,7 +3728,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index aa44f0c9bf..c4f2f881c9 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 331497bcfb..42c4df0262 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -318,8 +318,10 @@ extern bool CheckPromoteSignal(void);
 extern void WakeupRecovery(void);
 extern void SetWalWriterSleeping(bool sleeping);
 
+extern void StartupRequestWalReceiverRestart(void);
 extern void XLogRequestWalReceiverReply(void);
 
+extern void ProcessStartupSigHup(void);
 extern void assign_max_wal_size(int newval, void *extra);
 extern void assign_checkpoint_completion_target(double newval, void *extra);
 
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index d09ebe65a3..52585a1014 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 34;
+use Test::More tests => 35;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -345,6 +347,24 @@ is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
 
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");
+
 # Test physical slot advancing and its durability.  Create a new slot on
 # the primary, not used by any of the standbys. This reserves WAL at creation.
 my $phys_slot = 'phys_slot';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index b5de6c3237..c5160fe907 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4028,9 +4028,15 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           <varname>primary_conninfo</varname> string.
          </para>
          <para>
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if the server is not in standby mode.
          </para>
+         <para>
+          If <varname>primary_conninfo</varname> is changed while WAL receiver is running,
+          the WAL receiver shuts down and then restarts with new setting,
+          except when primary_conninfo is an empty string.
+         </para>
         </listitem>
        </varlistentry>
        <varlistentry id="guc-primary-slot-name" xreflabel="primary_slot_name">
@@ -4045,9 +4051,13 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
           connecting to the sending server via streaming replication to control
           resource removal on the upstream node
           (see <xref linkend="streaming-replication-slots"/>).
-          This parameter can only be set at server start.
+          This parameter can only be set in the <filename>postgresql.conf</filename>
+          file or on the server command line.
           This setting has no effect if <varname>primary_conninfo</varname> is not
-          set.
+          set or the server is not in standby mode.
+         </para>
+         <para>
+          The WAL receiver is restarted after an update of <varname>primary_slot_name</varname>.
          </para>
         </listitem>
        </varlistentry>
@@ -4163,7 +4173,11 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
         Specifies whether a WAL receiver should create a temporary replication
         slot on the remote instance when no permanent replication slot to use
         has been configured (using <xref linkend="guc-primary-slot-name"/>).
-        The default is off.  This parameter can only be set at server start.
+        The default is off.  This parameter can only be set in the 
+        <filename>postgresql.conf</filename> file or on the server command line.
+       </para>
+       <para>
+        The WAL receiver is restarted after an update of <varname>wal_receiver_create_temp_slot</varname>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index c7d93d3735..d3a299ba4c 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -816,9 +816,13 @@ static XLogSource readSource = XLOG_FROM_ANY;
  * currently have a WAL file open. If lastSourceFailed is set, our last
  * attempt to read from currentSource failed, and we should try another source
  * next.
+ *
+ * pendingWalRcvRestart is set when a config change occurs that requires a
+ * walreceiver restart.  This is only valid in XLOG_FROM_STREAM state.
  */
 static XLogSource currentSource = XLOG_FROM_ANY;
 static bool lastSourceFailed = false;
+static bool pendingWalRcvRestart = false;
 
 typedef struct XLogPageReadPrivate
 {
@@ -11905,6 +11909,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	for (;;)
 	{
 		XLogSource	oldSource = currentSource;
+		bool		startWalReceiver = false;
 
 		/*
 		 * First check if we failed to read from the current source, and
@@ -11939,54 +11944,11 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 						return false;
 
 					/*
-					 * If primary_conninfo is set, launch walreceiver to try
-					 * to stream the missing WAL.
-					 *
-					 * If fetching_ckpt is true, RecPtr points to the initial
-					 * checkpoint location. In that case, we use RedoStartLSN
-					 * as the streaming start position instead of RecPtr, so
-					 * that when we later jump backwards to start redo at
-					 * RedoStartLSN, we will have the logs streamed already.
-					 */
-					if (PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
-					{
-						XLogRecPtr	ptr;
-						TimeLineID	tli;
-
-						if (fetching_ckpt)
-						{
-							ptr = RedoStartLSN;
-							tli = ControlFile->checkPointCopy.ThisTimeLineID;
-						}
-						else
-						{
-							ptr = RecPtr;
-
-							/*
-							 * Use the record begin position to determine the
-							 * TLI, rather than the position we're reading.
-							 */
-							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
-
-							if (curFileTLI > 0 && tli < curFileTLI)
-								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
-									 (uint32) (tliRecPtr >> 32),
-									 (uint32) tliRecPtr,
-									 tli, curFileTLI);
-						}
-						curFileTLI = tli;
-						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
-											 PrimarySlotName,
-											 wal_receiver_create_temp_slot);
-						receivedUpto = 0;
-					}
-
-					/*
-					 * Move to XLOG_FROM_STREAM state in either case. We'll
-					 * get immediate failure if we didn't launch walreceiver,
-					 * and move on to the next state.
+					 * Move to XLOG_FROM_STREAM state, and set to start a
+					 * walreceiver if necessary.
 					 */
 					currentSource = XLOG_FROM_STREAM;
+					startWalReceiver = true;
 					break;
 
 				case XLOG_FROM_STREAM:
@@ -12138,7 +12100,71 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 					Assert(StandbyMode);
 
 					/*
-					 * Check if WAL receiver is still active.
+					 * First, shutdown walreceiver if its restart has been
+					 * requested -- but no point if we're already slated for
+					 * starting it.
+					 */
+					if (pendingWalRcvRestart && !startWalReceiver)
+					{
+						ShutdownWalRcv();
+
+						/*
+						 * Re-scan for possible new timelines if we were
+						 * requested to recover to the latest timeline.
+						 */
+						if (recoveryTargetTimeLineGoal ==
+							RECOVERY_TARGET_TIMELINE_LATEST)
+							rescanLatestTimeLine();
+
+						startWalReceiver = true;
+					}
+					pendingWalRcvRestart = false;
+
+					/*
+					 * Launch walreceiver if needed.
+					 *
+					 * If fetching_ckpt is true, RecPtr points to the initial
+					 * checkpoint location. In that case, we use RedoStartLSN
+					 * as the streaming start position instead of RecPtr, so
+					 * that when we later jump backwards to start redo at
+					 * RedoStartLSN, we will have the logs streamed already.
+					 */
+					if (startWalReceiver &&
+						PrimaryConnInfo && strcmp(PrimaryConnInfo, "") != 0)
+					{
+						XLogRecPtr	ptr;
+						TimeLineID	tli;
+
+						if (fetching_ckpt)
+						{
+							ptr = RedoStartLSN;
+							tli = ControlFile->checkPointCopy.ThisTimeLineID;
+						}
+						else
+						{
+							ptr = RecPtr;
+
+							/*
+							 * Use the record begin position to determine the
+							 * TLI, rather than the position we're reading.
+							 */
+							tli = tliOfPointInHistory(tliRecPtr, expectedTLEs);
+
+							if (curFileTLI > 0 && tli < curFileTLI)
+								elog(ERROR, "according to history file, WAL location %X/%X belongs to timeline %u, but previous recovered WAL file came from timeline %u",
+									 (uint32) (tliRecPtr >> 32),
+									 (uint32) tliRecPtr,
+									 tli, curFileTLI);
+						}
+						curFileTLI = tli;
+						RequestXLogStreaming(tli, ptr, PrimaryConnInfo,
+											 PrimarySlotName,
+											 wal_receiver_create_temp_slot);
+						receivedUpto = 0;
+					}
+
+					/*
+					 * Check if WAL receiver is active or wait to start up.
 					 */
 					if (!WalRcvStreaming())
 					{
@@ -12266,6 +12292,18 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 	return false;				/* not reached */
 }
 
+void
+StartupRequestWalReceiverRestart(void)
+{
+	if (currentSource == XLOG_FROM_STREAM && WalRcvRunning())
+	{
+		ereport(LOG,
+				(errmsg("wal receiver process shutdown requested")));
+
+		pendingWalRcvRestart = true;
+	}
+}
+
 /*
  * Determine what log level should be used to report a corrupt WAL record
  * in the current WAL page, previously read by XLogPageRead().
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index 32f02256ed..f3fea5132f 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -585,9 +585,9 @@ ReadPageInternal(XLogReaderState *state, XLogRecPtr pageptr, int reqLen)
 	/*
 	 * Data is not in our buffer.
 	 *
-	 * Every time we actually read the page, even if we looked at parts of it
-	 * before, we need to do verification as the read_page callback might now
-	 * be rereading data from a different source.
+	 * Every time we actually read the segment, even if we looked at parts of
+	 * it before, we need to do verification as the read_page callback might
+	 * now be rereading data from a different source.
 	 *
 	 * Whenever switching to a new WAL segment, we read the first page of the
 	 * file and validate its header, even if that's not where the target
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index 8952676765..fd9ac35dac 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -96,17 +96,51 @@ StartupProcShutdownHandler(SIGNAL_ARGS)
 	errno = save_errno;
 }
 
+/*
+ * Re-read the config file.
+ *
+ * If one of the critical walreceiver options has changed, flag xlog.c
+ * to restart it.
+ */
+static void
+StartupRereadConfig(void)
+{
+	char	   *conninfo = pstrdup(PrimaryConnInfo);
+	char	   *slotname = pstrdup(PrimarySlotName);
+	bool		tempSlot = wal_receiver_create_temp_slot;
+	bool		conninfoChanged;
+	bool		slotnameChanged;
+	bool		tempSlotChanged = false;
+
+	ProcessConfigFile(PGC_SIGHUP);
+
+	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
+	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
+
+	/*
+	 * wal_receiver_create_temp_slot is used only when we have no slot
+	 * configured.  We do not need to track this change if it has no effect.
+	 */
+	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
+		tempSlotChanged = tempSlot != wal_receiver_create_temp_slot;
+	pfree(conninfo);
+	pfree(slotname);
+
+	if (conninfoChanged || slotnameChanged || tempSlotChanged)
+		StartupRequestWalReceiverRestart();
+}
+
 /* Handle various signals that might be sent to the startup process */
 void
 HandleStartupProcInterrupts(void)
 {
 	/*
-	 * Check if we were requested to re-read config file.
+	 * Process any requests or signals received recently.
 	 */
 	if (got_SIGHUP)
 	{
 		got_SIGHUP = false;
-		ProcessConfigFile(PGC_SIGHUP);
+		StartupRereadConfig();
 	}
 
 	/*
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index a1459ca7f6..fad20986db 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -679,7 +679,11 @@ WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
 			   walrcv->walRcvState == WALRCV_STOPPING);
 		if (walrcv->walRcvState == WALRCV_RESTARTING)
 		{
-			/* we don't expect primary_conninfo to change */
+			/*
+			 * No need to handle changes in primary_conninfo or
+			 * primary_slotname here. Startup process will signal us in case
+			 * those change.
+			 */
 			*startpoint = walrcv->receiveStart;
 			*startpointTLI = walrcv->receiveStartTLI;
 			walrcv->walRcvState = WALRCV_STREAMING;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 2c3cbbaa68..53665971f5 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2050,7 +2050,7 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"wal_receiver_create_temp_slot", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
 		},
 		&wal_receiver_create_temp_slot,
@@ -3717,7 +3717,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_conninfo", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_conninfo", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the connection string to be used to connect to the sending server."),
 			NULL,
 			GUC_SUPERUSER_ONLY
@@ -3728,7 +3728,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"primary_slot_name", PGC_POSTMASTER, REPLICATION_STANDBY,
+		{"primary_slot_name", PGC_SIGHUP, REPLICATION_STANDBY,
 			gettext_noop("Sets the name of the replication slot to use on the sending server."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f2e55d1bd3..f01e43b818 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -309,9 +309,7 @@
 # These settings are ignored on a master server.
 
 #primary_conninfo = ''			# connection string to sending server
-					# (change requires restart)
 #primary_slot_name = ''			# replication slot on sending server
-					# (change requires restart)
 #promote_trigger_file = ''		# file name whose presence ends recovery
 #hot_standby = on			# "off" disallows queries during recovery
 					# (change requires restart)
@@ -323,7 +321,6 @@
 					# -1 allows indefinite delay
 #wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
 					# is not set.
-					# (change requires restart)
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index a4485efc00..2b1b67d35c 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -319,6 +319,7 @@ extern bool CheckPromoteSignal(void);
 extern void WakeupRecovery(void);
 extern void SetWalWriterSleeping(bool sleeping);
 
+extern void StartupRequestWalReceiverRestart(void);
 extern void XLogRequestWalReceiverReply(void);
 
 extern void assign_max_wal_size(int newval, void *extra);
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index d09ebe65a3..52585a1014 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -3,7 +3,7 @@ use strict;
 use warnings;
 use PostgresNode;
 use TestLib;
-use Test::More tests => 34;
+use Test::More tests => 35;
 
 # Initialize master node
 my $node_master = get_new_node('master');
@@ -208,7 +208,9 @@ $node_standby_2->append_conf('postgresql.conf',
 	"primary_slot_name = $slotname_2");
 $node_standby_2->append_conf('postgresql.conf',
 	"wal_receiver_status_interval = 1");
-$node_standby_2->restart;
+# should be able change primary_slot_name without restart
+# will wait effect in get_slot_xmins above
+$node_standby_2->reload;
 
 # Fetch xmin columns from slot's pg_replication_slots row, after waiting for
 # given boolean condition to be true to ensure we've reached a quiescent state
@@ -345,6 +347,24 @@ is($xmin, '', 'xmin of cascaded slot null with hs feedback reset');
 is($catalog_xmin, '',
 	'catalog xmin of cascaded slot still null with hs_feedback reset');
 
+note "check change primary_conninfo without restart";
+$node_standby_2->append_conf('postgresql.conf',
+	"primary_slot_name = ''");
+$node_standby_2->enable_streaming($node_master);
+$node_standby_2->reload;
+
+# be sure do not streaming from cascade
+$node_standby_1->stop;
+
+my $newval = $node_master->safe_psql('postgres',
+'INSERT INTO replayed(val) SELECT coalesce(max(val),0) + 1 AS newval FROM replayed RETURNING val'
+);
+$node_master->wait_for_catchup($node_standby_2, 'replay',
+	$node_master->lsn('insert'));
+my $is_replayed = $node_standby_2->safe_psql('postgres',
+	qq[SELECT 1 FROM replayed WHERE val = $newval]);
+is($is_replayed, qq(1), "standby_2 didn't replay master value $newval");
+
 # Test physical slot advancing and its durability.  Create a new slot on
 # the primary, not used by any of the standbys. This reserves WAL at creation.
 my $phys_slot = 'phys_slot';

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 2de21903a1..8983cb5f5e 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4170,8 +4170,8 @@ ANY <replaceable class="parameter">num_sync</replaceable> ( <replaceable class="
       <listitem>
        <para>
         Specifies whether the WAL receiver process should create a temporary replication
-        slot on the remote instance when no permanent replication slot to use
-        has been configured (using <xref linkend="guc-primary-slot-name"/>).
+        slot on the remote instance. The slot name can be configured
+        (using <xref linkend="guc-primary-slot-name"/>), otherwise it will be generated.
         The default is off.  This parameter can only be set in the 
         <filename>postgresql.conf</filename> file or on the server command line.
         If this parameter is changed while the WAL receiver process is running,
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index fd9ac35dac..134600db7d 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -116,13 +116,8 @@ StartupRereadConfig(void)
 
 	conninfoChanged = strcmp(conninfo, PrimaryConnInfo) != 0;
 	slotnameChanged = strcmp(slotname, PrimarySlotName) != 0;
+	tempSlotChanged = (tempSlot != wal_receiver_create_temp_slot);
 
-	/*
-	 * wal_receiver_create_temp_slot is used only when we have no slot
-	 * configured.  We do not need to track this change if it has no effect.
-	 */
-	if (!slotnameChanged && strcmp(PrimarySlotName, "") == 0)
-		tempSlotChanged = tempSlot != wal_receiver_create_temp_slot;
 	pfree(conninfo);
 	pfree(slotname);
 
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 760e3c7ab0..303e739b5b 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -245,12 +245,6 @@ WalReceiverMain(void)
 	startpoint = walrcv->receiveStart;
 	startpointTLI = walrcv->receiveStartTLI;
 
-	/*
-	 * At most one of is_temp_slot and slotname can be set; otherwise,
-	 * RequestXLogStreaming messed up.
-	 */
-	Assert(!is_temp_slot || (slotname[0] == '\0'));
-
 	/* Initialise to a sanish value */
 	walrcv->lastMsgSendTime =
 		walrcv->lastMsgReceiptTime = walrcv->latestWalEndTime = now;
@@ -365,14 +359,14 @@ WalReceiverMain(void)
 
 		/*
 		 * Create temporary replication slot if requested, and update slot
-		 * name in shared memory.  (Note the slot name cannot already be set
-		 * in this case.)
+		 * name in shared memory.
 		 */
 		if (is_temp_slot)
 		{
-			snprintf(slotname, sizeof(slotname),
-					 "pg_walreceiver_%lld",
-					 (long long int) walrcv_get_backend_pid(wrconn));
+			if (slotname[0] == '\0')
+				snprintf(slotname, sizeof(slotname),
+						"pg_walreceiver_%lld",
+						(long long int) walrcv_get_backend_pid(wrconn));
 
 			walrcv_create_slot(wrconn, slotname, true, 0, NULL);
 
diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c
index 21d1823607..28117883e1 100644
--- a/src/backend/replication/walreceiverfuncs.c
+++ b/src/backend/replication/walreceiverfuncs.c
@@ -218,7 +218,7 @@ ShutdownWalRcv(void)
  * "recptr" indicates the position where streaming should begin.  "conninfo"
  * is a libpq connection string to use.  "slotname" is, optionally, the name
  * of a replication slot to acquire.  "create_temp_slot" indicates to create
- * a temporary slot when no "slotname" is given.
+ * a temporary slot.
  *
  * WAL receivers do not directly load GUC parameters used for the connection
  * to the primary, and rely on the values passed down by the caller of this
@@ -254,23 +254,17 @@ RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr, const char *conninfo,
 	else
 		walrcv->conninfo[0] = '\0';
 
-	/*
-	 * Use configured replication slot if present, and ignore the value
-	 * of create_temp_slot as the slot name should be persistent.  Otherwise,
-	 * use create_temp_slot to determine whether this WAL receiver should
-	 * create a temporary slot by itself and use it, or not.
-	 */
 	if (slotname != NULL && slotname[0] != '\0')
 	{
 		strlcpy((char *) walrcv->slotname, slotname, NAMEDATALEN);
-		walrcv->is_temp_slot = false;
 	}
 	else
 	{
 		walrcv->slotname[0] = '\0';
-		walrcv->is_temp_slot = create_temp_slot;
 	}
 
+	walrcv->is_temp_slot = create_temp_slot;
+
 	if (walrcv->walRcvState == WALRCV_STOPPED)
 	{
 		launch = true;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 79bc7ac8ca..e702e3eddc 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2051,7 +2051,7 @@ static struct config_bool ConfigureNamesBool[] =
 
 	{
 		{"wal_receiver_create_temp_slot", PGC_SIGHUP, REPLICATION_STANDBY,
-			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot if no permanent slot is configured."),
+			gettext_noop("Sets whether a WAL receiver should create a temporary replication slot."),
 		},
 		&wal_receiver_create_temp_slot,
 		false,
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index e9f8ca775d..e09be86940 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -319,8 +319,7 @@
 #max_standby_streaming_delay = 30s	# max delay before canceling queries
 					# when reading streaming WAL;
 					# -1 allows indefinite delay
-#wal_receiver_create_temp_slot = off	# Create temp slot if primary_slot_name
-					# is not set.
+#wal_receiver_create_temp_slot = off	# Create temporary replication slot
 #wal_receiver_status_interval = 10s	# send replies at least this often
 					# 0 disables
 #hot_standby_feedback = off		# send info from standby to prevent

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a62d64eaa47..87fd5939246 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3699,7 +3699,7 @@ static struct config_string ConfigureNamesString[] =
 	},
 
 	{
-		{"restore_command", PGC_POSTMASTER, WAL_ARCHIVE_RECOVERY,
+		{"restore_command", PGC_SIGHUP, WAL_ARCHIVE_RECOVERY,
 			gettext_noop("Sets the shell command that will be called to retrieve an archived WAL file."),
 			NULL
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 9cb571f7cc7..9c9091e601e 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -253,7 +253,6 @@
 				# placeholders: %p = path of file to restore
 				#               %f = file name only
 				# e.g. 'cp /mnt/server/archivedir/%f %p'
-				# (change requires restart)
 #archive_cleanup_command = ''	# command to execute at every restartpoint
 #recovery_end_command = ''	# command to execute at completion of recovery