R-LOS产生，是信号劣化，误码过高，收光过低（小于-28dbm）。光功率过实能导致R-LOS。
ORA-01554：事务并发限制达到原因：string params：string，string,.原因：太多并发事务,.操作：关闭系统，...
ORA-01554 reason: no undo segment found with available slot CHANGES CAUSE _rollback_segment_count ...
ORA-01554: transaction concurrency limit reached reason:no undo segment found with available slot params:0, 02017-01-05 01:23:01 2017-01-05 01:23:01 S1000: [tp][ODBC Oracle driver][Oracle]ORA-12801: error signaled in parallel query server P0572017-01-05 01:23:01 ORA-01554: ...