Oracle V$SESSION_WAIT

zecaro發表於2011-04-03
OracleSessionAI

    在10gr2中，V$SESSION_WAIT的所有內容都可以在v$session中看到。

V$SESSION_WAIT displays 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:

  • P1RAW, P2RAW, and P3RAW display the same values as the P1, P2, and P3 columns, except that the numbers are displayed in hexadecimal.

P1RAW, P2RAW, and P3RAW 是 P1, P2, and P3 的十六進位制表示

  • The WAIT_TIME column contains a value of -2 on 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 the TIMED_STATISTICS initialization parameter to true. Remember that doing this has a small negative effect on system performance.

WAIT_TIME =-2表示所在平臺不支援 fast timing mechanism。如果想要此列顯示等待時間，必須將TIMED_STATISTICS 設定為ture。這將對系統系能帶來一些微小的副作用。

In previous releases, the WAIT_TIME column 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 列使用一個非常大的值來表示所在平臺不支援 fast timing mechanism，而不是負數（如前所述）。

  • The STATE column interprets the value of WAIT_TIME and describes the state of the current or most recent wait.

 STATE列的數值將影響WAIT_TIME 表達的含義，並且STATE列表示當前狀態還是最近一次等待。

Column Datatype Description
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:

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時間；等於零時表示正在等待。

SECONDS_IN_WAIT NUMBER

If WAIT_TIME = 0, then SECONDS_IN_WAIT is the seconds spent in the current wait condition. If WAIT_TIME > 0, then SECONDS_IN_WAIT is the seconds since the start of the last wait, and SECONDS_IN_WAIT - WAIT_TIME / 100 is the active seconds since the last wait ended.

wait_time=0，表示正在等待的已經花費的時間（單位：秒）。wait_time>0，表示距離上次等待開始的時間（單位：秒）。而SECONDS_IN_WAIT - WAIT_TIME / 100表示自從上次等待後結束後的active的時間（單位：秒）。

STATE VARCHAR2(19) Wait state:

  • 0 - WAITING (the session is currently waiting)

0 表示正在等待。

  • -2 - WAITED UNKNOWN TIME (duration of last wait is unknown)

-2表示上次等待時間未知。

  • -1 - WAITED SHORT TIME (last wait <1/100th of a second)

-1表示上次等待時間很短，小於百分之一秒。

  • >0 - WAITED KNOWN TIME (WAIT_TIME = duration of last wait)

>0表示上次等待時間。


來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/23650854/viewspace-691632/，如需轉載，請註明出處，否則將追究法律責任。

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