*** a/src/backend/access/transam/xlog.c
--- b/src/backend/access/transam/xlog.c
***************
*** 8904,8909 **** XLogReportParameters(void)
--- 8904,8910 ----
  		{
  			XLogRecData rdata;
  			xl_parameter_change xlrec;
+ 			XLogRecPtr	recptr;
  
  			xlrec.MaxConnections = MaxConnections;
  			xlrec.max_worker_processes = max_worker_processes;
***************
*** 8917,8923 **** XLogReportParameters(void)
  			rdata.len = sizeof(xlrec);
  			rdata.next = NULL;
  
! 			XLogInsert(RM_XLOG_ID, XLOG_PARAMETER_CHANGE, &rdata);
  		}
  
  		ControlFile->MaxConnections = MaxConnections;
--- 8918,8925 ----
  			rdata.len = sizeof(xlrec);
  			rdata.next = NULL;
  
! 			recptr = XLogInsert(RM_XLOG_ID, XLOG_PARAMETER_CHANGE, &rdata);
! 			XLogFlush(recptr);
  		}
  
  		ControlFile->MaxConnections = MaxConnections;