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 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,'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,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$lock s
WHERE request != 0
AND s.id1 = m.id1
AND s.id2 = m.id2)
)
ORDER BY id1,id2,m.request;
robin@SZDB:~/dba_scripts/custom/sql> more request_lock_detail.sql
set linesize 190
col osuser format a15
col username format a20 wrap
col object_name format a20 wrap
col terminal format a25 wrap
col Req_Mode format a20
select B.SID,C.USERNAME,C.OSUSER,C.TERMINAL,DECODE(B.ID2,A.OBJECT_NAME,'Trans-'||to_char(B.ID1)) OBJECT_NAME,B.TYPE,DECODE(B.LMODE,'--Waiting--','Row Excl','Sha Row Exc','Other') "Lock Mode",DECODE(B.REQUEST,' ','Other') "Req_Mode"
from DBA_OBJECTS A,V$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;