Oracle的锁表与解锁.doc

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,gram,s.osuserFROM v$session s,v$lock l,dba_objects oWHERE l.sid = s.sidAND l.id1 = o.object_id(+)AND s.username is NOT Null-kill session语句alter system kill session50,492;-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, s.serial#, l.locked_mode,l.oracle_username,l.os_user_name,s.machine, s.terminal, o.object_name, s.logon_timeFROM v$locked_object l, all_objects o, v$session sWHERE l.object_id = o.object_idAND l.session_id = s.sidORDER 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actionSELECT l.session_id sid, s.serial#, l.locked_mode, l.oracle_username, s.user#,l.os_user_name,s.machine, s.terminal,a.sql_text, a.actionFROM v$sqlarea a,v$session s, v$locked_object lWHERE l.session_id = s.sidAND s.prev_sql_addr = a.addressORDER BY sid, s.serial#;-3.查出锁定表的sid, serial#,os_user_name, machine_name, terminal，锁的type,modeSELECT s.sid, s.serial#, s.username, s.schemaname, s.osuser, cess, s.machine,s.terminal, s.logon_time, l.typeFROM v$session s, v$lock lWHERE s.sid = l.sidAND s.username IS NOT NULLORDER BY sid;这个语句将查找到数据库中所有的DML语句产生的锁，还可以发现，任何DML语句其实产生了两个锁，一个是表锁，一个是行锁。杀锁命令alter system kill session sid,serial#SELECT /*+ rule */ s.username,decode(l.type,TM,TABLE LOCK,TX,ROW LOCK,NULL) LOCK_LEVEL,o.owner,o.object_name,o.object_type,s.sid,s.serial#,s.terminal,s.machine,gram,s.osuserFROM v$session s,v$lock l,dba_objects oWHERE l.sid = s.sidAND l.id1 = o.object_id(+)AND s.username is NOT NULL如果发生了锁等待，我们可能更想知道是谁锁了表而引起谁的等待以下的语句可以查询到谁锁了表，而谁在等待。以上查询结果是一个树状结构，如果有子节点，则表示有等待发生。如果想知道锁用了哪个回滚段，还可以关联到V$rollname，其中xidusn就是回滚段的USNcol user_name format a10col owner format a10col object_name format a10col object_type format a10SELECT /*+ rule */ lpad( ,decode(l.xidusn ,0,3,0)|l.oracle_username User_name,o.owner,o.object_name,o.object_type,s.sid,s.serial#FROM v$locked_o