九乡新闻网高屋良树有多有钱:Oracle V$SESSION
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V$SESSION_WAITdisplays the resources or events for which active sessions are waiting.
V$SESSION_WAIT展示了active的session等待的resources or events 。
The following are tuning considerations:
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P1RAW,P2RAW, andP3RAWdisplay the same values as theP1,P2, andP3columns, except that the numbers are displayed in hexadecimal.
P1RAW,
P2RAW, andP3RAW是P1,P2, andP3的十六进制表示
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The
WAIT_TIMEcolumn contains a value of-2on platforms that do not support a fast timing mechanism. If you are running on one of these platforms and you want this column to reflect true wait times, then you must set theTIMED_STATISTICSinitialization parameter totrue. Remember that doing this has a small negative effect on system performance.
WAIT_TIME=-2表示所在平台不支持 fast timing mechanism。如果想要此列显示等待时间，必须将TIMED_STATISTICS设置为ture。这将对系统系能带来一些微小的副作用。
In previous releases, the
WAIT_TIMEcolumn contained an arbitrarily large value instead of a negative value to indicate the platform. did not have a fast timing mechanism.在更早的版本，WAIT_TIME列使用一个非常大的值来表示所在平台不支持 fast timing mechanism，而不是负数（如前所述）。
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The
STATEcolumn interprets the value ofWAIT_TIMEand describes the state of the current or most recent wait.
STATE列的数值将影响WAIT_TIME表达的含义，并且STATE列表示当前状态还是最近一次等待。
SID NUMBER Session identifier SEQ# NUMBER Sequence number that uniquely identifies this wait.Incremented for each wait. EVENT VARCHAR2(64) Resource or event for which the session is waiting See Also:Appendix C, "Oracle Wait Events"
P1TEXT VARCHAR2(64) Description of the first additional parameter P1 NUMBER First additional parameter P1RAW RAW(4) First additional parameter P2TEXT VARCHAR2(64) Description of the second additional parameter P2 NUMBER Second additional parameter P2RAW RAW(4) Second additional parameter P3TEXT VARCHAR2(64) Description of the third additional parameter P3 NUMBER Third additional parameter P3RAW RAW(4) Third additional parameter WAIT_CLASS_ID NUMBER Identifier of the wait class WAIT_CLASS# NUMBER Number of the wait class WAIT_CLASS VARCHAR2(64) Name of the wait class WAIT_TIME NUMBER A nonzero value is the session's last wait time. A zero value means the session is currently waiting.
非零值表示上一次等待时间；等于零时表示正在等待。
SECONDS_IN_WAIT NUMBER IfWAIT_TIME=0, thenSECONDS_IN_WAITis the seconds spent in the current wait condition. IfWAIT_TIME>0, thenSECONDS_IN_WAITis the seconds since the start of the last wait, andSECONDS_IN_WAIT-WAIT_TIME/100is the active seconds since the last wait ended.
wait_time=0，表示正在等待的已经花费的时间（单位：秒）。wait_time>0，表示距离上次等待开始的时间（单位：秒）。而SECONDS_IN_WAIT-WAIT_TIME/100表示自从上次等待后结束后的active的时间（单位：秒）。
STATE VARCHAR2(19) Wait state: -
0 - WAITING(the session is currently waiting)
0 表示正在等待。
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-2 - WAITED UNKNOWN TIME(duration of last wait is unknown)
-2表示上次等待时间未知。
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-1 - WAITED SHORT TIME(last wait <1/100th of a second)
-1表示上次等待时间很短，小于百分之一秒。
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>0 - WAITED KNOWN TIME(WAIT_TIME= duration of last wait)
>0表示上次等待时间。