session视图中wait_time
V$SESSION
|
WAIT_TIME
|
NUMBER
|
If the session is currently waiting, then the value is
0
. If the session is not in a wait, then the value is as follows:
>
0
- Value is the duration of the last wait in hundredths of a second
-1
- Duration of the last wait was less than a hundredth of a second
-2
- Parameter
TIMED_STATISTICS
was set to
false
This column has been deprecated in favor of the columns
WAIT_TIME_MICRO
and
STATE
.
|
1.当会话的state为waiting时，wait_time为0.
2.wait_time 大于0时，指的是从上一次waiting到当前非waiting状态的间隔时间，单位为1/100秒。
3.wait_time为-1时，指的是从上一次waiting到当前非waiting状态的间隔时间小于1/100秒。
4.wait_time为-2时，TIMED_STATISTICS 设成了fasle。
V$ACTIVE_SESSION_HISTORY
|
WAIT_TIME
|
NUMBER
|
0
if the session was waiting at the time of sampling
Total wait time for the event for which the session last waited if the session was on the CPU when sampled
Whether or not
WAIT_TIME
=
0
is what is useful to find the
SESSION_STATE
at the time of sampling, rather than the actual value of
WAIT_TIME
itself.
Maps to V$SESSION.WAIT_TIME
.
|
1.wait_time为0 ，当在采样时，会话状态是waiting。
2.wait_time大于0,当在采样时，会话状态是on cpu，这个值便是从往上最后一次状态为waitting到当前的时间区间。
3.这里的采样频率是1s.
DBA_HIST_ACTIVE_SESS_HISTORY
|
WAIT_TIME
|
NUMBER
|
|
Total wait time (in microseconds) for the event for which the session last waited (
0
if currently waiting)
|
1.wait_time为0 ，当在采样时，会话状态是waiting。
2.wait_time大于0,当在采样时，会话状态是on cpu，这个值便是从往上最后一次状态为waitting到当前的时间区间。
3.这里的采样频率是10s.