diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index fa1db748b5e..6a252fcf454 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -1151,6 +1151,8 @@ static void
 WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 				bool last_write)
 {
+	TimestampTz	now;
+
 	/* output previously gathered data in a CopyData packet */
 	pq_putmessage_noblock('d', ctx->out->data, ctx->out->len);
 
@@ -1160,23 +1162,54 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 	 * several releases by streaming physical replication.
 	 */
 	resetStringInfo(&tmpbuf);
-	pq_sendint64(&tmpbuf, GetCurrentTimestamp());
+	now = GetCurrentTimestamp();
+	pq_sendint64(&tmpbuf, now);
 	memcpy(&ctx->out->data[1 + sizeof(int64) + sizeof(int64)],
 		   tmpbuf.data, sizeof(int64));
 
-	/* fast path */
+	CHECK_FOR_INTERRUPTS();
+
 	/* Try to flush pending output to the client */
 	if (pq_flush_if_writable() != 0)
 		WalSndShutdown();
 
-	if (!pq_is_send_pending())
+	/* Try taking fast path unless we get too close to walsender timeout. */
+	if (now < TimestampTzPlusMilliseconds(last_reply_timestamp,
+										  wal_sender_timeout / 2) &&
+		!pq_is_send_pending())
+	{
 		return;
+	}
 
+	/* If we have pending write here, go to slow path */
 	for (;;)
 	{
 		int			wakeEvents;
 		long		sleeptime;
-		TimestampTz now;
+
+		/* Check for input from the client */
+		ProcessRepliesIfAny();
+
+		now = GetCurrentTimestamp();
+
+		/* die if timeout was reached */
+		WalSndCheckTimeOut(now);
+
+		/* Send keepalive if the time has come */
+		WalSndKeepaliveIfNecessary(now);
+
+		if (!pq_is_send_pending())
+			break;
+
+		sleeptime = WalSndComputeSleeptime(now);
+
+		wakeEvents = WL_LATCH_SET | WL_POSTMASTER_DEATH |
+			WL_SOCKET_WRITEABLE | WL_SOCKET_READABLE | WL_TIMEOUT;
+
+		/* Sleep until something happens or we time out */
+		WaitLatchOrSocket(MyLatch, wakeEvents,
+						  MyProcPort->sock, sleeptime,
+						  WAIT_EVENT_WAL_SENDER_WRITE_DATA);
 
 		/*
 		 * Emergency bailout if postmaster has died.  This is to avoid the
@@ -1198,34 +1231,9 @@ WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
 			SyncRepInitConfig();
 		}
 
-		/* Check for input from the client */
-		ProcessRepliesIfAny();
-
 		/* Try to flush pending output to the client */
 		if (pq_flush_if_writable() != 0)
 			WalSndShutdown();
-
-		/* If we finished clearing the buffered data, we're done here. */
-		if (!pq_is_send_pending())
-			break;
-
-		now = GetCurrentTimestamp();
-
-		/* die if timeout was reached */
-		WalSndCheckTimeOut(now);
-
-		/* Send keepalive if the time has come */
-		WalSndKeepaliveIfNecessary(now);
-
-		sleeptime = WalSndComputeSleeptime(now);
-
-		wakeEvents = WL_LATCH_SET | WL_POSTMASTER_DEATH |
-			WL_SOCKET_WRITEABLE | WL_SOCKET_READABLE | WL_TIMEOUT;
-
-		/* Sleep until something happens or we time out */
-		WaitLatchOrSocket(MyLatch, wakeEvents,
-						  MyProcPort->sock, sleeptime,
-						  WAIT_EVENT_WAL_SENDER_WRITE_DATA);
 	}
 
 	/* reactivate latch so WalSndLoop knows to continue */