Oracle 查詢鎖之間的依賴關係

Oracle 查詢鎖之間的依賴關係

注釋：

  該SQL可查詢多會話,非select的DML操作,同時操作A表引起的鎖 ..會話之間的關係~

  ....下文有該SQL用到的視圖/欄位的詳細注釋..

  ....若想顯示其他欄位可以按照自己需求增加 .. 

SQL:

SELECT DISTINCT S.SID , /*會話的唯一標識，通常要對某個會話進行分析前，首先就需要獲得該會話的SID。*/

                --S.SERIAL# /*會話的序號*/,

                S.STATE /*WAIT STATE~*/ ,

                S.BLOCKING_SESSION ,

                --SESSION IDENTIFIER OF THE BLOCKING SESSION. THIS COLUMN IS VALID ONLY IF BLOCKING_SESSION_STATUS HAS THE VALUE VALID.

                S.BLOCKING_SESSION_STATUS STATUS, /*THIS COLUMN PROVIDES DETAILS ON WHETHER THERE IS A BLOCKING SESSION: */

                ( CASE

                  WHEN SQL_TEXT IS NULL /*LO.REQUEST = 0 */

                  THEN

                  '(SID:' || S.SID || ')會話 SQL已跑完'

                  ELSE

                  '(SID:' || S.SID || ')會話 正執行SQL：' || SQL_.SQL_TEXT

                END ) SQL_TEXT /*執行完的SQL'SQL_TEXT標記SQL已跑完，否則標記SQL'*/ ,

                --SQL_.SQL_FULLTEXT SQL全文本,

                S.USERNAME /*建立該會話的使用者名稱*/ ,

                O.OWNER || '.' || O.OBJECT_NAME 鎖的對象, --V$SESSION.ROW_WAIT_OBJ#若操作完的該欄位值=-1，所以關聯的V$LOCKED_OBJECT取鎖表

                LO.REQUEST  , -- Lock mode in which the process requests the lock 會話申請的鎖的模式

                S.EVENT  ,

                S.MACHINE /*用戶端的機器名。*/ ,

                S.LOGON_TIME /*登陸時間*/ ,

                'ALTER SYSTEM KILL SESSION ''' || S.SID || ',' || S.SERIAL# || ''';' KILL --若存在鎖情況,會用到KILL鎖釋放~

  FROM V$SESSION S

  LEFT JOIN V$SQL SQL_

    ON SQL_.SQL_ID = S.SQL_ID

  JOIN V$LOCKED_OBJECT L

    ON L.SESSION_ID = S.SID

  JOIN ALL_OBJECTS O

    ON L.OBJECT_ID = O.OBJECT_ID

  JOIN V$LOCK LO

    ON (LO.BLOCK != 0 OR LO.REQUEST != 0 )

    --V$LOCK.block => A value of either 0 or 1, depending on whether or not the lock in question is the blocker

    --V$LOCK.REQUEST => Lock mode in which the process requests the lock:下文有值的意義~ ['0 - none']

  WHERE LO.SID = L.SESSION_ID

  AND LO.SID = S.SID

  ORDER BY S.BLOCKING_SESSION DESC ;
 

注釋：

--視圖==官網注釋

 

--v$session        ==    http://docs.Oracle.com/cd/E11882_01/server.112/e40402/dynviews_3016.htm#REFRN30223

--V$SQL            ==    http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_3043.htm#REFRN30246

--V$LOCK          ==    http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_2027.htm#REFRN30121

--V$LOCKED_OBJECT  ==    http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_2030.htm#REFRN30125

--ALL_OBJECTS      ==    http://docs.oracle.com/cd/E11882_01/server.112/e40402/statviews_1158.htm#REFRN20146

 

 

--顯示欄位==官網注釋：

V$SESSION.STATE = Wait state :

 

--WAITING - Session is currently waiting

--WAITED UNKNOWN TIME - Duration of the last wait is unknown; this is the value when the parameter TIMED_STATISTICS is set to false

--WAITED SHORT TIME - Last wait was less than a hundredth of a second

--WAITED KNOWN TIME - Duration of the last wait is specified in the WAIT_TIME column  S.BLOCKING_SESSION ,

--Session identifier of the blocking session. This column is valid only if BLOCKING_SESSION_STATUS has the value VALID.

V$SESSION.BLOCKING_SESSION_STATUS = This column provides details on whether there is a blocking session :

 

--VALID - there is a blocking session, and it is identified in the BLOCKING_INSTANCE and BLOCKING_SESSION columns

--NO HOLDER - there is no session blocking this session

--NOT IN WAIT - this session is not in a wait

--UNKNOWN - the blocking session is unknown

V$LOCK.REQUEST = Lock mode in which the process requests the lock :

 

--0 - none

--1 - null (NULL)

--2 - row-S (SS)

--3 - row-X (SX)

--4 - share (S)

--5 - S/Row-X (SSX)

--6 - exclusive (X)