[大数据]oracle锁表查询及释放进程

oracle锁表：

在数据的操作过程可能会出现

1. 表锁
2. 行锁
3. 间隙锁
4. …

假设是单线程出现数据库锁了的情况，那么会导致后面的任务都无法执行，所以出现数据锁要及时释放进程

oracle查看进程

select b.sid,b.serial#
　　from v$locked_object a,v$session b
　　where a.session_id = b.sid group by b.sid,b.serial#;

oracle释放锁

declare cursor mycur is
select b.sid,b.serial#
　　from v$locked_object a,v$session b
　　where a.session_id = b.sid group by b.sid,b.serial#;
begin
  for cur in mycur
    loop  
     execute immediate ( 'alter system  kill session  '''||cur.sid || ','|| cur.SERIAL# ||''' ');
     end loop;
end;

详细说明

1.1、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;

1.2、查看被锁的表

select b.owner,b.object_name,a.session_id,a.locked_mode from v$locked_object a,dba_objects b where b.object_id = a.object_id;

1.3、查看那个用户那个进程照成死锁

select b.username,b.sid,b.serial#,logon_time from v$locked_object a,v$session b where a.session_id = b.sid order by b.logon_time;

1.4、查看连接的进程

SELECT sid, serial#, username, osuser FROM v$session;

1.5、查出锁定表的信息

1. 这个语句将查找到数据库中所有的DML语句产生的锁
2. 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.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;

1.5、杀掉进程

alter system kill session'sid值,serial#的值';