Oracle阻塞(blockingblocked)实例详解

 --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_env SPID        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         1 pts/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=7788 sid=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_type USERNAME               SID TY LMODE    REQUEST      ID1    ID2 ------------------------------ ---------- -- ----------- ----------- ---------- ---------- SCOTT                1073 TX Exclusive  None      524319   27412 LESHAMI               1067 TX None    Exclusive    524319   27412 GOEX_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.program FROM v$process p, v$session s WHERE 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$sqlarea SELECT   'sid=' || a.SID || ' Wait Class=' || a.wait_class || ' Time=' || a.seconds_in_wait || CHR (10) || ' Query=' || b.sql_text FROM v$session a, v$sqlarea b WHERE a.blocking_session IS NOT NULL AND a.sql_address = b.address ORDER BY a.blocking_session / robin@SZDB:~/dba_scripts/custom/sql> more request_lock_type.sql --This script generates a report of users waiting for locks. --Access Privileges: SELECT on v$session, v$lock SELECT sn.username, m.sid, m.type, DECODE(m.lmode, 0, 'None', 1, 'Null', 2, 'Row Share', 3, 'Row Excl.', 4, 'Share', 5, 'S/Row Excl.', 6, 'Exclusive', lmode, ltrim(to_char(lmode,'990'))) lmode, DECODE(m.request,0, 'None', 1, 'Null', 2, 'Row Share', 3, 'Row Excl.', 4, 'Share', 5, 'S/Row Excl.', 6, 'Exclusive', request, ltrim(to_char(m.request, '990'))) request, m.id1, m.id2 FROM v$session sn, v$lock m WHERE (sn.sid = m.sid AND m.request != 0) OR (sn.sid = m.sid AND m.request = 0 AND lmode != 4 AND (id1, id2) IN (SELECT s.id1, s.id2 FROM v$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.sql set linesize 190 col osuser format a15 col username format a20 wrap col object_name format a20 wrap col terminal format a25 wrap col Req_Mode format a20 select 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 C where A.OBJECT_ID(+) = B.ID1 and B.SID = C.SID and C.USERNAME is not null order by B.SID, B.ID2;