查询session等待的事件
select s.sid,
s.username,
s.program,
s.status,
se.event, --等待时间的名称
se.total_waits, --会话等待时间的总数
se.total_timeouts, --会话超时事件总数
se.time_waited, --等待事件的总事件(百分之一秒)
se.average_wait --事件等待的平均事件(百分之一秒)
from v$session s, v$session_event se
Where s.sid = se.sid
And se.event not like 'SQL*Net%'
And s.status = 'ACTIVE'
And s.username is not null
v$session_event里有些字段不清楚，特意查询了下：
v$session_event：
v$session_event 记录了session自启动以来所有的等待事件。
- SQL> desc v$session_event
- Name Null? Type
- ----------------------------------------- -------- ----------------------------
- SID NUMBER 会话ID
- EVENT VARCHAR2(64) 等待事件的名称
- TOTAL_WAITS NUMBER 会话等待事件总数
- TOTAL_TIMEOUTS NUMBER 会话超时事件总数
- TIME_WAITED NUMBER 等待事件的总时间（百分之一秒）
- AVERAGE_WAIT NUMBER 事件等待的平均时间（百分之一秒）
- MAX_WAIT NUMBER 最大等待时间（百分之一秒）
- TIME_WAITED_MICRO NUMBER 等待事件的总时间（微秒）
- EVENT_ID NUMBER 等待事件的标识符
- WAIT_CLASS_ID NUMBER 等待事件的类标识符
- WAIT_CLASS# NUMBER 等待事件的类的唯一编号
- WAIT_CLASS VARCHAR2(64) 等待事件类的名称
v$session_event 记录了当前session的等待事件，这些信息最终被累积进入v$system_event视图。
顺便记录下v$system_event视图
v$system_event：
v$system_event 提供了自实例启动后各个等待事件的概括。
- SQL> desc v$system_event
- Name Null? Type
- ----------------------------------------- -------- ----------------------------
- EVENT VARCHAR2(64) 等待事件的名称
- TOTAL_WAITS NUMBER 等待事件总数
- TOTAL_TIMEOUTS NUMBER 超时事件总数
- TIME_WAITED NUMBER 等待事件的总时间（百分之一秒）
- AVERAGE_WAIT NUMBER 事件等待的平均时间（百分之一秒）
- TIME_WAITED_MICRO NUMBER 等待事件的总时间（微秒）
- EVENT_ID NUMBER 等待事件的标识符
- WAIT_CLASS_ID NUMBER 等待事件的类标识符
- WAIT_CLASS# NUMBER 等待事件的类的唯一编号
- WAIT_CLASS VARCHAR2(64) 等待事件类的名称
查看系统的各项等待，按等待事件总数排序
- SQL> select event,total_waits,total_timeouts,time_waited,average_wait from v$system_event order by total_waits desc;
- EVENT TOTAL_WAITS TOTAL_TIMEOUTS TIME_WAITED AVERAGE_WAIT
- ---------------------------------------------------------------- ----------- -------------- ----------- ------------
- rdbms ipc message 20927 20313 6532187 312.14
- db file sequential read 6831 0 2957 .43
- control file sequential read 6445 0 27 0
- jobq slave wait 2298 2192 673056 292.89
- control file parallel write 2182 0 1670 .77
- pmon timer 2128 2125 617029 289.96
- log file parallel write 812 0 1482 1.82
- db file scattered read 515 0 357 .69
- Streams AQ: qmn coordinator idle wait 452 227 611876 1353.71
- Streams AQ: qmn slave idle wait 224 0 610886 2727.17
- virtual circuit status 211 210 615410 2916.63
- EVENT TOTAL_WAITS TOTAL_TIMEOUTS TIME_WAITED AVERAGE_WAIT
- ---------------------------------------------------------------- ----------- -------------- ----------- ------------
- log file sync 116 0 365 3.14
- dispatcher timer 105 105 610962 5818.68
- LGWR wait for redo copy 87 0 1 .01
- SQL*Net message to client 85 0 0 0
- SQL*Net message from client 84 0 284450 3386.31
- os thread startup 32 0 254 7.93
- SQL*Net more data to client 26 0 0 0
- smon timer 26 20 578859 22263.82
- direct path read 18 0 0 0
- rdbms ipc reply 14 0 97 6.92
- latch: shared pool 10 0 3 .29
- EVENT TOTAL_WAITS TOTAL_TIMEOUTS TIME_WAITED AVERAGE_WAIT
- ---------------------------------------------------------------- ----------- -------------- ----------- ------------
- read by other session 9 0 145 16.15
- SQL*Net break/reset to client 9 0 0 .04
- library cache load lock 7 0 21 2.93
- log file single write 7 0 2 .24
- log file sequential read 7 0 8 1.18
- direct path write 6 0 0 0
- latch free 5 0 154 30.85
- direct path read temp 3 0 0 0
- enq: CF - contention 3 0 46 15.24
- cursor: pin S wait on X 3 3 3 1.09
- JS external job 3 0 197 65.83
- EVENT TOTAL_WAITS TOTAL_TIMEOUTS TIME_WAITED AVERAGE_WAIT
- ---------------------------------------------------------------- ----------- -------------- ----------- ------------
- enq: PR - contention 3 0 13 4.45
- Streams AQ: qmn coordinator waiting for slave to start 2 0 7 3.64
- Streams AQ: waiting for time management or cleanup tasks 2 1 77111 38555.65
- instance state change 2 0 0 .01
- latch: redo allocation 2 0 0 .05
- latch: cache buffers lru chain 2 0 0 .07
- latch: library cache 1 0 0 .09
- buffer busy waits 1 0 0 .4
- control file heartbeat 1 1 391 390.92
- reliable message 1 0 1 .58
- 已选择43行。