*** a/src/backend/access/transam/xlog.c
--- b/src/backend/access/transam/xlog.c
***************
*** 1867,1876 **** XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch)
  			}
  
  			issue_xlog_fsync(openLogFile, openLogSegNo);
- 
- 			/* signal that we need to wakeup walsenders later */
- 			WalSndWakeupRequest();
  		}
  		LogwrtResult.Flush = LogwrtResult.Write;
  	}
  
--- 1867,1877 ----
  			}
  
  			issue_xlog_fsync(openLogFile, openLogSegNo);
  		}
+ 
+ 		/* signal that we need to wakeup walsenders later */
+ 		WalSndWakeupRequest();
+ 
  		LogwrtResult.Flush = LogwrtResult.Write;
  	}