diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index a09ceb2..b21b4c0 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2091,7 +2091,7 @@ include_dir 'conf.d'
         Specifies whether transaction commit will wait for WAL records
         to be written to disk before the command returns a <quote>success</>
         indication to the client.  Valid values are <literal>on</>,
-        <literal>remote_write</>, <literal>local</>, and <literal>off</>.
+        <literal>remote_write</>, <literal> remote_apply</>, <literal>local</>, and <literal>off</>.
         The default, and safe, setting
         is <literal>on</>.  When <literal>off</>, there can be a delay between
         when success is reported to the client and when the transaction is
@@ -2125,6 +2125,10 @@ include_dir 'conf.d'
         ensure data preservation even if the standby instance of
         <productname>PostgreSQL</> were to crash, but not if the standby
         suffers an operating-system-level crash.
+        When set to <literal>remote_apply</>, commits will wait until a reply
+        from the current synchronous stanbyindicates it has received the
+        commit record of the transaction and applied it, so that it has become
+        visible to queries.
        </para>
        <para>
         When synchronous
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 6cb690c..2600fba 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -1081,6 +1081,9 @@ primary_slot_name = 'node_a_slot'
     WAL record is then sent to the standby. The standby sends reply
     messages each time a new batch of WAL data is written to disk, unless
     <varname>wal_receiver_status_interval</> is set to zero on the standby.
+    In the case that <varname>synchronous_commit</> is set to
+    <literal>remote_apply</>, the standby sends reply messages when the commit
+    record is replayed, making the transaction visible.
     If the standby is the first matching standby, as specified in
     <varname>synchronous_standby_names</> on the primary, the reply
     messages from that standby will be used to wake users waiting for
@@ -1107,6 +1110,14 @@ primary_slot_name = 'node_a_slot'
    </para>
 
    <para>
+    Setting <varname>synchronous_commit</> to <literal>remote_apply</> will
+    cause each commit to wait until the current synchronous standby reports
+    that it has replayed the transaction, making it visible to user queries.
+    In simple cases, this allows for load balancing with causal consistency
+    on a single hot standby.
+   </para>
+
+   <para>
     Users will stop waiting if a fast shutdown is requested.  However, as
     when using asynchronous replication, the server will not fully
     shutdown until all outstanding WAL records are transferred to the currently
@@ -1160,9 +1171,10 @@ primary_slot_name = 'node_a_slot'
     <title>Planning for High Availability</title>
 
    <para>
-    Commits made when <varname>synchronous_commit</> is set to <literal>on</>
-    or <literal>remote_write</> will wait until the synchronous standby responds. The response
-    may never occur if the last, or only, standby should crash.
+    Commits made when <varname>synchronous_commit</> is set to <literal>on</>,
+    <literal>remote_write</> or <literal>remote_apply</> will wait until the
+    synchronous standby responds. The response may never occur if the last, or
+    only, standby should crash.
    </para>
 
    <para>
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index b491735..5e8cc3d 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -5121,6 +5121,13 @@ XactLogCommitRecord(TimestampTz commit_time,
 		xl_xinfo.xinfo |= XACT_COMPLETION_FORCE_SYNC_COMMIT;
 
 	/*
+	 * Check if the caller would like to ask standbys for immediate feedback
+	 * once this commit is applied.
+	*/
+	if (synchronous_commit >= SYNCHRONOUS_COMMIT_REMOTE_APPLY)
+		xl_xinfo.xinfo |= XACT_COMPLETION_SYNC_APPLY_FEEDBACK;
+
+	/*
 	 * Relcache invalidations requires information about the current database
 	 * and so does logical decoding.
 	 */
@@ -5456,6 +5463,13 @@ xact_redo_commit(xl_xact_parsed_commit *parsed,
 	if (XactCompletionForceSyncCommit(parsed->xinfo))
 		XLogFlush(lsn);
 
+	/*
+	 * If asked by the primary (because someone is waiting for a synchronous
+	 * commit = remote_apply), we will need to ask walreceiver to send a
+	 * reply immediately.
+	 */
+	if (XactCompletionSyncApplyFeedback(parsed->xinfo))
+		XLogRequestWalReceiverReply();
 }
 
 /*
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 00f139a..0519357 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -346,6 +346,12 @@ static XLogRecPtr RedoRecPtr;
 static bool doPageWrites;
 
 /*
+ * doRequestWalReceiverReply is used by recovery code to ask the main recovery
+ * loop to trigger a walreceiver reply.
+ */
+static bool doRequestWalReceiverReply;
+
+/*
  * RedoStartLSN points to the checkpoint's REDO location which is specified
  * in a backup label file, backup history file or control file. In standby
  * mode, XLOG streaming usually starts from the position where an invalid
@@ -6909,6 +6915,19 @@ StartupXLOG(void)
 				XLogCtl->lastReplayedTLI = ThisTimeLineID;
 				SpinLockRelease(&XLogCtl->info_lck);
 
+				/*
+				 * If rm_redo reported that it applied a commit record that
+				 * the master is waiting for by calling
+				 * XLogRequestWalReceiverReply, then we wake up the receiver
+				 * so that it notices the updated lastReplayedEndRecPtr and
+				 * sends a reply to the master.
+				 */
+				if (doRequestWalReceiverReply)
+				{
+					doRequestWalReceiverReply = false;
+					WalRcvWakeup();
+				}
+
 				/* Remember this record as the last-applied one */
 				LastRec = ReadRecPtr;
 
@@ -11630,3 +11649,13 @@ SetWalWriterSleeping(bool sleeping)
 	XLogCtl->WalWriterSleeping = sleeping;
 	SpinLockRelease(&XLogCtl->info_lck);
 }
+
+/*
+ * Called by redo code to indicate that the xlog replay loop should wake up
+ * the walreceiver process so that a reply can be sent to the primary.
+ */
+void
+XLogRequestWalReceiverReply(void)
+{
+	doRequestWalReceiverReply = true;
+}
diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index 92faf4e..4565348 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -416,6 +416,7 @@ SyncRepReleaseWaiters(void)
 	WalSnd	   *syncWalSnd;
 	int			numwrite = 0;
 	int			numflush = 0;
+	int			numapply = 0;
 
 	/*
 	 * If this WALSender is serving a standby that is not on the list of
@@ -462,12 +463,18 @@ SyncRepReleaseWaiters(void)
 		walsndctl->lsn[SYNC_REP_WAIT_FLUSH] = MyWalSnd->flush;
 		numflush = SyncRepWakeQueue(false, SYNC_REP_WAIT_FLUSH);
 	}
+	if (walsndctl->lsn[SYNC_REP_WAIT_APPLY] < MyWalSnd->apply)
+	{
+		walsndctl->lsn[SYNC_REP_WAIT_APPLY] = MyWalSnd->apply;
+		numapply = SyncRepWakeQueue(false, SYNC_REP_WAIT_APPLY);
+	}
 
 	LWLockRelease(SyncRepLock);
 
-	elog(DEBUG3, "released %d procs up to write %X/%X, %d procs up to flush %X/%X",
+	elog(DEBUG3, "released %d procs up to write %X/%X, %d procs up to flush %X/%X, %d procs up to apply %X/%x",
 		 numwrite, (uint32) (MyWalSnd->write >> 32), (uint32) MyWalSnd->write,
-	   numflush, (uint32) (MyWalSnd->flush >> 32), (uint32) MyWalSnd->flush);
+		 numflush, (uint32) (MyWalSnd->flush >> 32), (uint32) MyWalSnd->flush,
+		 numapply, (uint32) (MyWalSnd->apply >> 32), (uint32) MyWalSnd->apply);
 
 	/*
 	 * If we are managing the highest priority standby, though we weren't
@@ -728,6 +735,9 @@ assign_synchronous_commit(int newval, void *extra)
 		case SYNCHRONOUS_COMMIT_REMOTE_FLUSH:
 			SyncRepWaitMode = SYNC_REP_WAIT_FLUSH;
 			break;
+		case SYNCHRONOUS_COMMIT_REMOTE_APPLY:
+			SyncRepWaitMode = SYNC_REP_WAIT_APPLY;
+			break;
 		default:
 			SyncRepWaitMode = SYNC_REP_NO_WAIT;
 			break;
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 7b36e02..c19842e 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -101,6 +101,7 @@ static uint32 recvOff = 0;
  */
 static volatile sig_atomic_t got_SIGHUP = false;
 static volatile sig_atomic_t got_SIGTERM = false;
+static volatile sig_atomic_t got_SIGUSR2 = false;
 
 /*
  * LogstreamResult indicates the byte positions that we have already
@@ -150,9 +151,27 @@ static void ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime);
 /* Signal handlers */
 static void WalRcvSigHupHandler(SIGNAL_ARGS);
 static void WalRcvSigUsr1Handler(SIGNAL_ARGS);
+static void WalRcvSigUsr2Handler(SIGNAL_ARGS);
 static void WalRcvShutdownHandler(SIGNAL_ARGS);
 static void WalRcvQuickDieHandler(SIGNAL_ARGS);
 
+static void WalRcvBlockSigUsr2(void)
+{
+	sigset_t mask;
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGUSR2);
+	sigprocmask(SIG_BLOCK, &mask, NULL);
+}
+
+static void WalRcvUnblockSigUsr2(void)
+{
+	sigset_t mask;
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGUSR2);
+	sigprocmask(SIG_UNBLOCK, &mask, NULL);
+}
 
 static void
 ProcessWalRcvInterrupts(void)
@@ -200,6 +219,7 @@ WalReceiverMain(void)
 	WalRcvData *walrcv = WalRcv;
 	TimestampTz last_recv_timestamp;
 	bool		ping_sent;
+	bool		forceReply;
 
 	/*
 	 * WalRcv should be set up already (if we are a backend, we inherit this
@@ -268,7 +288,7 @@ WalReceiverMain(void)
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, WalRcvSigUsr1Handler);
-	pqsignal(SIGUSR2, SIG_IGN);
+	pqsignal(SIGUSR2, WalRcvSigUsr2Handler);
 
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
@@ -299,6 +319,10 @@ WalReceiverMain(void)
 	/* Unblock signals (they were blocked when the postmaster forked us) */
 	PG_SETMASK(&UnBlockSig);
 
+	/* Block SIGUSR2 (we unblock it only during network waits). */
+	WalRcvBlockSigUsr2();
+	got_SIGUSR2 = false;
+
 	/* Establish the connection to the primary for XLOG streaming */
 	EnableWalRcvImmediateExit();
 	walrcv_connect(conninfo);
@@ -408,7 +432,9 @@ WalReceiverMain(void)
 				}
 
 				/* Wait a while for data to arrive */
+				WalRcvUnblockSigUsr2();
 				len = walrcv_receive(NAPTIME_PER_CYCLE, &buf);
+				WalRcvBlockSigUsr2();
 				if (len != 0)
 				{
 					/*
@@ -439,11 +465,21 @@ WalReceiverMain(void)
 							endofwal = true;
 							break;
 						}
+						WalRcvUnblockSigUsr2();
 						len = walrcv_receive(0, &buf);
+						WalRcvBlockSigUsr2();
+					}
+
+					if (got_SIGUSR2)
+					{
+						/* The recovery process asked us to force a reply. */
+						got_SIGUSR2 = false;
+						forceReply = true;
 					}
 
 					/* Let the master know that we received some data. */
-					XLogWalRcvSendReply(false, false);
+					XLogWalRcvSendReply(forceReply, false);
+					forceReply = false;
 
 					/*
 					 * If we've written some records, flush them to disk and
@@ -498,7 +534,14 @@ WalReceiverMain(void)
 						}
 					}
 
-					XLogWalRcvSendReply(requestReply, requestReply);
+					if (got_SIGUSR2)
+					{
+						/* The recovery process asked us to force a reply. */
+						got_SIGUSR2 = false;
+						forceReply = true;
+					}
+					XLogWalRcvSendReply(requestReply || forceReply, requestReply);
+					forceReply = false;
 					XLogWalRcvSendHSFeedback(false);
 				}
 			}
@@ -740,6 +783,13 @@ WalRcvSigUsr1Handler(SIGNAL_ARGS)
 	errno = save_errno;
 }
 
+/* SIGUSR2: used to receive wakeups from recovery */
+static void
+WalRcvSigUsr2Handler(SIGNAL_ARGS)
+{
+	got_SIGUSR2 = true;
+}
+
 /* SIGTERM: set flag for main loop, or shutdown immediately if safe */
 static void
 WalRcvShutdownHandler(SIGNAL_ARGS)
@@ -1222,6 +1272,22 @@ ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
 }
 
 /*
+ * Wake up the walreceiver if it happens to be blocked in walrcv_receive,
+ * and tell it that a commit record has been applied.
+ *
+ * This is called by the startup process whenever interesting xlog records
+ * are applied, so that walreceiver can check if it needs to send an apply
+ * notification back to the master which may be waiting in a COMMIT with
+ * synchronous_commit = remote_apply.
+ */
+void
+WalRcvWakeup(void)
+{
+	if (WalRcv->pid != 0)
+		kill(WalRcv->pid, SIGUSR2);
+}
+
+/*
  * Return a string constant representing the state. This is used
  * in system functions and views, and should *not* be translated.
  */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index ea5a09a..a8eaa5f 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -345,12 +345,13 @@ static const struct config_enum_entry constraint_exclusion_options[] = {
 };
 
 /*
- * Although only "on", "off", "remote_write", and "local" are documented, we
- * accept all the likely variants of "on" and "off".
+ * Although only "on", "off", "remote_apply", "remote_write", and "local" are
+ * documented, we accept all the likely variants of "on" and "off".
  */
 static const struct config_enum_entry synchronous_commit_options[] = {
 	{"local", SYNCHRONOUS_COMMIT_LOCAL_FLUSH, false},
 	{"remote_write", SYNCHRONOUS_COMMIT_REMOTE_WRITE, false},
+	{"remote_apply", SYNCHRONOUS_COMMIT_REMOTE_APPLY, false},
 	{"on", SYNCHRONOUS_COMMIT_ON, false},
 	{"off", SYNCHRONOUS_COMMIT_OFF, false},
 	{"true", SYNCHRONOUS_COMMIT_ON, true},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index ee3d378..085099c 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -177,7 +177,7 @@
 					# (change requires restart)
 #fsync = on				# turns forced synchronization on or off
 #synchronous_commit = on		# synchronization level;
-					# off, local, remote_write, or on
+					# off, local, remote_write, remote_apply, or on
 #wal_sync_method = fsync		# the default is the first option
 					# supported by the operating system:
 					#   open_datasync
diff --git a/src/include/access/xact.h b/src/include/access/xact.h
index ebeb582..ed8d22c 100644
--- a/src/include/access/xact.h
+++ b/src/include/access/xact.h
@@ -60,7 +60,9 @@ typedef enum
 	SYNCHRONOUS_COMMIT_LOCAL_FLUSH,		/* wait for local flush only */
 	SYNCHRONOUS_COMMIT_REMOTE_WRITE,	/* wait for local flush and remote
 										 * write */
-	SYNCHRONOUS_COMMIT_REMOTE_FLUSH		/* wait for local and remote flush */
+	SYNCHRONOUS_COMMIT_REMOTE_FLUSH,	/* wait for local and remote flush */
+	SYNCHRONOUS_COMMIT_REMOTE_APPLY		/* wait for local flush and remote
+										 * apply */
 }	SyncCommitLevel;
 
 /* Define the default setting for synchonous_commit */
@@ -144,10 +146,13 @@ typedef void (*SubXactCallback) (SubXactEvent event, SubTransactionId mySubid,
  * EOXact... routines which run at the end of the original transaction
  * completion.
  */
+#define XACT_COMPLETION_SYNC_APPLY_FEEDBACK		(1U << 29)
 #define XACT_COMPLETION_UPDATE_RELCACHE_FILE	(1U << 30)
 #define XACT_COMPLETION_FORCE_SYNC_COMMIT		(1U << 31)
 
 /* Access macros for above flags */
+#define XactCompletionSyncApplyFeedback(xinfo) \
+	(!!(xinfo & XACT_COMPLETION_SYNC_APPLY_FEEDBACK))
 #define XactCompletionRelcacheInitFileInval(xinfo) \
 	(!!(xinfo & XACT_COMPLETION_UPDATE_RELCACHE_FILE))
 #define XactCompletionForceSyncCommit(xinfo) \
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index ecd30ce..68e20e4 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -268,6 +268,8 @@ extern bool CheckPromoteSignal(void);
 extern void WakeupRecovery(void);
 extern void SetWalWriterSleeping(bool sleeping);
 
+extern void XLogRequestWalReceiverReply(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/include/replication/syncrep.h b/src/include/replication/syncrep.h
index 96e059b..28b68f6 100644
--- a/src/include/replication/syncrep.h
+++ b/src/include/replication/syncrep.h
@@ -23,8 +23,9 @@
 #define SYNC_REP_NO_WAIT		-1
 #define SYNC_REP_WAIT_WRITE		0
 #define SYNC_REP_WAIT_FLUSH		1
+#define SYNC_REP_WAIT_APPLY		2
 
-#define NUM_SYNC_REP_WAIT_MODE	2
+#define NUM_SYNC_REP_WAIT_MODE	3
 
 /* syncRepState */
 #define SYNC_REP_NOT_WAITING		0
diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index 6eacb09..3294df9 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -162,5 +162,6 @@ extern void RequestXLogStreaming(TimeLineID tli, XLogRecPtr recptr,
 extern XLogRecPtr GetWalRcvWriteRecPtr(XLogRecPtr *latestChunkStart, TimeLineID *receiveTLI);
 extern int	GetReplicationApplyDelay(void);
 extern int	GetReplicationTransferLatency(void);
+extern void WalRcvWakeup(void);
 
 #endif   /* _WALRECEIVER_H */