Oracle的锁表与解锁

Oracle的锁表与解锁

SELECT /*+ rule */ 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,dba_objects o
WHERE l.sid = s.sid
AND l.id1 = o.object_id(+)
AND s.username is NOT Null

--kill session语句
alter system kill session'50,492';
--以下几个为相关表
SELECT * FROM v$lock;
SELECT * FROM v$sqlarea;
SELECT * FROM v$session;
SELECT * FROM v$process ;
SELECT * FROM v$locked_object;
SELECT * FROM all_objects;
SELECT * FROM v$session_wait;
--1.查出锁定object的session的信息以及被锁定的object名
SELECT l.session_id sid,l.locked_mode,l.oracle_username,
l.os_user_name,s.logon_time
FROM v$locked_object l,all_objects o,v$session s
WHERE l.object_id = o.object_id
AND l.session_id = s.sid
ORDER BY sid,s.serial# ;
--2.查出锁定表的session的sid,serial#,os_user_name,machine name,terminal和执行的语句
--比上面那段多出sql_text和action
SELECT l.session_id sid,s.user#,a.sql_text,a.action
FROM v$sqlarea a,v$session s,v$locked_object l
WHERE l.session_id = s.sid
AND s.prev_sql_addr = a.address
ORDER BY sid,s.serial#;
--3.查出锁定表的sid,machine_name,terminal，锁的type,mode
SELECT s.sid,s.username,s.schemaname,s.osuser,s.process,
s.terminal,s.logon_time,l.type
FROM v$session s,v$lock l
WHERE s.sid = l.sid
AND s.username IS NOT NULL
ORDER BY sid;

这个语句将查找到数据库中所有的DML语句产生的锁，还可以发现，
任何DML语句其实产生了两个锁，一个是表锁，一个是行锁。
杀锁命令
alter system kill session 'sid,serial#' SELECT /*+ rule */ s.username,decode(l.type,'TX',NULL) LOCK_LEVEL,o.owner,s.sid,s.osuser FROM v$session s,dba_objects o WHERE l.sid = s.sid AND l.id1 = o.object_id(+) AND s.username is NOT NULL 如果发生了锁等待，我们可能更想知道是谁锁了表而引起谁的等待 以下的语句可以查询到谁锁了表，而谁在等待。 以上查询结果是一个树状结构，如果有子节点，则表示有等待发生。 如果想知道锁用了哪个回滚段，还可以关联到V$rollname，其中xidusn就是回滚段的USN col user_name format a10 col owner format a10 col object_name format a10 col object_type format a10 SELECT /*+ rule */ lpad(' ',decode(l.xidusn,3,0))||l.oracle_username User_name,s.serial# FROM v$locked_object l,dba_objects o,v$session s WHERE l.object_id=o.object_id AND l.session_id=s.sid ORDER BY o.object_id,xidusn DESC