等待事件之查询方法 v$system_wait_class

select * from v$system_wait_class order by time_waited

WAIT_CLASS_ID WAIT_CLASS# WAIT_CLASS                                                       TOTAL_WAITS TIME_WAITED TOTAL_WAITS_FG TIME_WAITED_FG
------------- ----------- ---------------------------------------------------------------- ----------- ----------- -------------- --------------
   2396326234          10 Scheduler                                                            8537847      829643        8534586  827164
   1893977003           0 Other                                                               49655639     3055163       19893495 2456901
   2000153315           7 Network                                                           2.3123E+10    32812574     2.3089E+1032790990
   3875070507           4 Concurrency                                                        216817537    55508356      21411209851809805
   4166625743           3 Administrative                                                      30823378   108076823            492    1825
   3290255840           2 Configuration                                                       82484167   134092961       82407455      133492120
   4217450380           1 Application                                                         50229527   163406691       49025102      163368374
   4108307767           9 System I/O                                                        1849454213   176128079     114106445359848969
   3386400367           5 Commit                                                             704658072   234911585      704639511      234874630
   1740759767           8 User I/O                                                          5.6918E+10  2809335426     5.6902E+10     2802472056
   2723168908           6 Idle                                                              2.1572E+10  2.8072E+11     2.0893E+10     2.3483E+11

11 rows selected.

 

可以看出数据库的主要等待消耗在User I/0操作上。