oracle对select加锁方法、锁的查询

一、oracle对select加锁方法
create table test(a number,b number);
insert into test values(1,2);
insert into test values(3,4);
insert into test values(8,9);
commit;
---session 1 模拟选中一个号码
SQL> select * from test where a =1 for update skip locked;
         A          B
---------- ----------
         1          2
---session 2 对a=1再进行select
SQL> select * from test where a = 1 for update skip locked;
未选定行
-- session 3 全表select
SQL> select * from test for update skip locked;
         A          B
---------- ----------
         3          4
         8          9
SQL>
二、查询那些用户，操纵了那些表造成了锁机
SELECT  s.username,
decode(l.type,'TM','TABLE LOCK',
'TX','ROW LOCK',
NULL) LOCK_LEVEL,
o.owner,o.object_name,o.object_type,
s.sid,s.serial#,s.terminal,s.machine,s.program,s.osuser
from v$session s,v$lock l,all_objects o
WHERE l.sid = s.sid
AND l.id1 = o.object_id(+)
AND s.username is NOT Null
三、查出被锁的表，和锁住这个表的会话ID
select a.session_id ,b.* from v$locked_object a,all_objects b
where a.object_id=b.object_id
四、 查出对应的SQL语句
select vs.SQL_TEXT,vsess.sid,vsess.SERIAL#,vsess.MACHINE,vsess.OSUSER
,vsess.TERMINAL,vsess.PROGRAM,vs.CPU_TIME,vs.DISK_READS
from v$sql vs,v$session vsess
where vs.ADDRESS=vsess.SQL_ADDRESS
and vsess.sid=(上面查出来的会话ID)
五、
１.查哪个过程被锁
查V$DB_OBJECT_CACHE视图:
SELECT * from V$DB_OBJECT_CACHE WHERE OWNER='过程的所属用户' AND LOCKS!='0';
2. 查是哪一个SID,通过SID可知道是哪个SESSION.
查V$ACCESS视图: