Oracle的锁表与解锁

秒速五厘米 2022-04-14 05:18 292阅读 0赞

转载[http://www.cnblogs.com/swcjd][http_www.cnblogs.com_swcjd]

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, s.serial#, l.locked_mode,l.oracle_username,
    l.os_user_name,s.machine, s.terminal, o.object_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.serial#, l.locked_mode, l.oracle_username, s.user#,
    l.os_user_name,s.machine, s.terminal,a.sql_text, a.action
    FROM v$sqlarea a,v$session s, v$locked_object l
    WHERE l.session_id = s.sid
    AND s.prev_sql_addr = a.address
    ORDER BY sid, s.serial#;
    --3.查出锁定表的sid, serial#,os_user_name, machine_name, terminal，锁的type,mode
    SELECT s.sid, s.serial#, s.username, s.schemaname, s.osuser, s.process, s.machine,
    s.terminal, s.logon_time, l.type
    FROM v$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,'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
    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$rollname，其中xidusn就是回滚段的USN
    col user_name format a10
    col owner format a10
    col object_name format a10
    col object_type format a10
    SELECT /*+ rule */ lpad(' ',decode(l.xidusn ,0,3,0))||l.oracle_username User_name,
    o.owner,o.object_name,o.object_type,s.sid,s.serial#
    FROM v$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

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