ORACLE数据库锁查看：

SELECT a.username,decode(b.type,'TM','TABLE LOCK','TX','ROW LOCK',NULL) LOCK_LEVEL,
c.owner,c.object_name,c.object_type,
a.sid,a.serial#,a.terminal,a.machine,a.program,a.osuser
FROM v$session a,v$lock b,dba_objects c
WHERE b.sid = a.sid
AND b.id1 = c.object_id(+)
AND a.username is NOT Null;


而解锁就更简单了

alter system kill session 'sid,serial#';

1 获取锁信息：



select * from gp_toolkit.gp_locks_on_relation ;

视图实现：



select pgl.locktype AS lorlocktype, pgl.database AS lordatabase, pgc.relname AS lorrelname, pgl.relation AS lorrelation, pgl.transaction AS lortransaction, pgl.pid AS lorpid, pgl.mode AS lormode, pgl.granted AS lorgranted, pgsa.current_query AS lorcurrentquery
FROM pg_locks pgl
JOIN pg_class pgc ON pgl.relation = pgc.oid
JOIN pg_stat_activity pgsa ON pgl.pid = pgsa.procpid
ORDER BY pgc.relname;


  
（如果gp_toolkit没有安装，则： psql -f $GPHOME/share/postgresql/gp_toolkit.sql）




2 获取当前正在运行的SQL：



select *from pg_stat_activity;



3 结束SQL进程：



pg_cancel_backend



pg_terminate_backend

查看数据库锁表和解锁

select object_name,machine,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;
alter system kill session ‘131,7885’;

今天启动项目时发现项目启动报错Could not open JDBC Connection for transaction，weblogic控制台上服务器也有警告。网上提示是根据实际操做确认连接池不足，程序在获取连接完成数据库操作后，没有及时关闭连接。但是按照网上提供的方法改了之后仍然报错，后发现是数据库锁表了。

可以根据以下代码查看数据库中有哪些表锁住了
select c.id,c.serial#,c.username,c.osuser,b.owner,b.object_name,a.locked_mode,p.spid from v$locked_object a, dba_objects b, v$session c, v$process p where a.OBJECT_ID = b.OBJECT_ID and a.SESSION_ID = c.SID and c.PADDR = p.ADDR;

查询出具体用户具体哪种表锁住之后 ，我们可以根据查询的sid和serial#解锁
alter system kill session 'sid,serial#';

执行完语句后，重新启动项目就可以了