[Oracle]锁表与解锁

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