*** a/src/backend/replication/walsender.c
--- b/src/backend/replication/walsender.c
***************
*** 1151,1156 **** static void
--- 1151,1158 ----
  WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
  				bool last_write)
  {
+ 	TimestampTz now = GetCurrentTimestamp();
+ 
  	/* output previously gathered data in a CopyData packet */
  	pq_putmessage_noblock('d', ctx->out->data, ctx->out->len);
  
***************
*** 1160,1235 **** WalSndWriteData(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,
  	 * several releases by streaming physical replication.
  	 */
  	resetStringInfo(&tmpbuf);
! 	pq_sendint64(&tmpbuf, GetCurrentTimestamp());
  	memcpy(&ctx->out->data[1 + sizeof(int64) + sizeof(int64)],
  		   tmpbuf.data, sizeof(int64));
  
- 	/* fast path */
- 	/* Try to flush pending output to the client */
- 	if (pq_flush_if_writable() != 0)
- 		WalSndShutdown();
- 
- 	if (!pq_is_send_pending())
- 		return;
- 
  	for (;;)
  	{
  		int			wakeEvents;
  		long		sleeptime;
  		TimestampTz now;
  
  		/*
! 		 * Emergency bailout if postmaster has died.  This is to avoid the
! 		 * necessity for manual cleanup of all postmaster children.
  		 */
! 		if (!PostmasterIsAlive())
! 			exit(1);
! 
! 		/* Clear any already-pending wakeups */
! 		ResetLatch(MyLatch);
! 
! 		CHECK_FOR_INTERRUPTS();
! 
! 		/* Process any requests or signals received recently */
! 		if (ConfigReloadPending)
! 		{
! 			ConfigReloadPending = false;
! 			ProcessConfigFile(PGC_SIGHUP);
! 			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 */
- 	SetLatch(MyLatch);
  }
  
  /*
--- 1162,1238 ----
  	 * several releases by streaming physical replication.
  	 */
  	resetStringInfo(&tmpbuf);
! 	pq_sendint64(&tmpbuf, now);
  	memcpy(&ctx->out->data[1 + sizeof(int64) + sizeof(int64)],
  		   tmpbuf.data, sizeof(int64));
  
  	for (;;)
  	{
  		int			wakeEvents;
  		long		sleeptime;
  		TimestampTz now;
  
+ 		if (now <= TimestampTzPlusMilliseconds(last_reply_timestamp,
+ 											   wal_sender_timeout / 2))
+ 		{
+ 			/* fast path */
+ 			/* Try to flush pending output to the client */
+ 			if (pq_flush_if_writable() != 0)
+ 				WalSndShutdown();
+ 		}
+ 		else
+ 		{
+ 			/*
+ 			 * Emergency bailout if postmaster has died.  This is to avoid the
+ 			 * necessity for manual cleanup of all postmaster children.
+ 			 */
+ 			if (!PostmasterIsAlive())
+ 				exit(1);
+ 
+ 			CHECK_FOR_INTERRUPTS();
+ 
+ 			/* Process any requests or signals received recently */
+ 			if (ConfigReloadPending)
+ 			{
+ 				ConfigReloadPending = false;
+ 				ProcessConfigFile(PGC_SIGHUP);
+ 				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;
+ 
+ 			/* die if timeout was reached */
+ 			WalSndCheckTimeOut(now);
+ 
+ 			/* Send keepalive if the time has come */
+ 			WalSndKeepaliveIfNecessary(now);
+ 		}
+ 
+ 		/* return if finished */
+ 		if (!pq_is_send_pending())
+ 			return;
+ 
  		/*
! 		 * Send buffer is filled up. Being different from WalSndLoop, since
! 		 * this function is called at a commit time for all the modifications
! 		 * within the commit, we should continue sending data without waiting
! 		 * for the next WAL record.
! 		 *
! 		 * Not sure how long we should wait for a room to send more data, but
! 		 * 1ms would be sufficient.
  		 */
! 		pg_usleep(1000);
  		now = GetCurrentTimestamp();
  	}
  }
  
  /*