Oracle 阻塞(blocking blocked)介绍和实例演示

--更新表，注，提示符scott@CNMMBO表明用户为scott的session，用户名不同，session不同。scott@CNMMBO> update emp set sal=sal*1.1 where empno=7788;1 row updated.scott@CNMMBO> @my_envSPID    SID SERIAL# USERNAME  PROGRAM------------ ---------- ---------- --------------- ------------------------------------------------11205    1073  4642 robin   oracle@SZDB (TNS V1-V3)--另起两个session更新同样的行，这两个session都会处于等待，直到第一个session提交或回滚leshami@CNMMBO> update scott.emp set sal=sal+100 where empno=7788;goex_admin@CNMMBO> update scott.emp set sal=sal-50 where empno=7788;--下面在第一个session 查询阻塞情况scott@CNMMBO> @blocker BLOCK_MSG            BLOCK-------------------------------------------------- ----------pts/5 ('1073,4642') is blocking 1067,10438     1pts/5 ('1073,4642') is blocking 1065,4464     1--上面的结果表明session 1073,4642 阻塞了后面的2个--即session 1073,4642是阻塞者，后面2个session是被阻塞者--Author : Leshami--Blog : http://blog.csdn.net/leshami--下面查询正在阻塞的session id，SQL语句以及被阻塞的时间scott@CNMMBO> @blocking_session_detail.sql'SID='||A.SID||'WAITCLASS='||A.WAIT_CLASS||'TIME='||A.SECONDS_IN_WAIT||CHR(10)||'QUERY='||B.SQL_TEXT-------------------------------------------------------------------------------------------------------sid=1067 Wait Class=Application Time=5995 Query=update scott.emp set sal=sal+100 where empno=7788sid=1065 Wait Class=Application Time=225 Query=update scott.emp set sal=sal-50 where empno=7788--下面的查询阻塞时锁的持有情况 scott@CNMMBO> @request_lock_typeUSERNAME        SID TY LMODE  REQUEST   ID1  ID2------------------------------ ---------- -- ----------- ----------- ---------- ----------SCOTT        1073 TX Exclusive None   524319  27412LESHAMI        1067 TX None  Exclusive  524319  27412GOEX_ADMIN       1065 TX None  Exclusive  524319  27412--可以看到LESHAMI，GOEX_ADMIN 2个用户都在请求524319/27412上的Exclusive锁，而此时已经被SCOTT加了Exclusive锁--查询阻塞时锁的持有详细信息scott@CNMMBO> @request_lock_detail  SID USERNAME    OSUSER   TERMINAL     OBJECT_NAME   TY Lock Mode Req_Mode---------- -------------------- --------------- ------------------------- -------------------- -- ----------- --------------------  1065 GOEX_ADMIN   robin   pts/1      EMP     TM Row Excl  1065 GOEX_ADMIN   robin   pts/1      Trans-524319   TX --Waiting-- Exclusive  1067 LESHAMI    robin   pts/0      EMP     TM Row Excl  1067 LESHAMI    robin   pts/0      Trans-524319   TX --Waiting-- Exclusive  1073 SCOTT    robin   pts/5      EMP     TM Row Excl  1073 SCOTT    robin   pts/5      Trans-524319   TX Exclusive 

robin@SZDB:~/dba_scripts/custom/sql> more my_env.sql SELECT spid, s.sid, s.serial#, p.username, p.programFROM v$process p, v$session sWHERE p.addr = s.paddr  AND s.sid = (SELECT sid     FROM v$mystat     WHERE rownum = 1);robin@SZDB:~/dba_scripts/custom/sql> more blocker.sql col block_msg format a50; select c.terminal||' ('''||a.sid||','||c.serial#||''') is blocking '||b.sid||','||d.serial# block_msg, a.block from v$lock a,v$lock b,v$session c,v$session d  where a.id1=b.id1  and a.id2=b.id2  and a.block>0 and a.sid <>b.sid  and a.sid=c.sid  and b.sid=d.SID; robin@SZDB:~/dba_scripts/custom/sql> more blocking_session_detail.sql--To find the query for blocking session--Access Privileges: SELECT on v$session, v$sqlareaSELECT  'sid='   || a.SID   || ' Wait Class='   || a.wait_class   || ' Time='   || a.seconds_in_wait   || CHR (10)   || ' Query='   || b.sql_text FROM v$session a, v$sqlarea b WHERE a.blocking_session IS NOT NULL AND a.sql_address = b.addressORDER BY a.blocking_session/robin@SZDB:~/dba_scripts/custom/sql> more request_lock_type.sql--This script generates a report of users waiting for locks.--Access Privileges: SELECT on v$session, v$lockSELECT sn.username, m.sid, m.type,  DECODE(m.lmode, 0, 'None',      1, 'Null',      2, 'Row Share',      3, 'Row Excl.',      4, 'Share',      5, 'S/Row Excl.',      6, 'Exclusive',    lmode, ltrim(to_char(lmode,'990'))) lmode,  DECODE(m.request,0, 'None',       1, 'Null',       2, 'Row Share',       3, 'Row Excl.',       4, 'Share',       5, 'S/Row Excl.',       6, 'Exclusive',       request, ltrim(to_char(m.request,    '990'))) request, m.id1, m.id2FROM v$session sn, v$lock mWHERE (sn.sid = m.sid AND m.request != 0)  OR (sn.sid = m.sid    AND m.request = 0 AND lmode != 4    AND (id1, id2) IN (SELECT s.id1, s.id2  FROM v$lock s      WHERE request != 0    AND s.id1 = m.id1        AND s.id2 = m.id2)    )ORDER BY id1, id2, m.request; robin@SZDB:~/dba_scripts/custom/sql> more request_lock_detail.sqlset linesize 190col osuser format a15col username format a20 wrapcol object_name format a20 wrapcol terminal format a25 wrapcol Req_Mode format a20select B.SID, C.USERNAME, C.OSUSER, C.TERMINAL,  DECODE(B.ID2, 0, A.OBJECT_NAME,   'Trans-'||to_char(B.ID1)) OBJECT_NAME,  B.TYPE,  DECODE(B.LMODE,0,'--Waiting--',      1,'Null',      2,'Row Share',      3,'Row Excl',     4,'Share',      5,'Sha Row Exc',   6,'Exclusive',      'Other') "Lock Mode",  DECODE(B.REQUEST,0,' ',      1,'Null',      2,'Row Share',      3,'Row Excl',      4,'Share',      5,'Sha Row Exc',      6,'Exclusive',      'Other') "Req_Mode" from DBA_OBJECTS A, V$LOCK B, V$SESSION Cwhere A.OBJECT_ID(+) = B.ID1 and B.SID = C.SID and C.USERNAME is not nullorder by B.SID, B.ID2;