--查看数据库最大连接数

select value from v$parameter where name = 'processes';

--更改数据库连接数

alter system set processes =  scope = spfile;

--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;

--查看当前活跃线程数

select s.status,s.* from v$session s  where schemaname='数据库用户名' and machine='机器名';

select sid,serial#,username,program,machine,status from v$session;

select count(*) from v$session;

--查看sql执行记录

select * from v$sqltext  where sql_text like '%sql语句%';

--查询锁表语句

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#;

--查看oracle正在执行的任务

select a.program,a.osuser, a.sql_exec_start, b.spid, c.sql_text,c.SQL_ID, c.FIRST_LOAD_TIME, c.last_load_time, c.last_active_time

from v$session a, v$process b, v$sqlarea c

where a.paddr = b.addr

and a.sql_hash_value = c.hash_value

and a.username is not null;

--查出oracle当前的被锁对象

SELECT l.session_id sid,

       s.serial#,

       l.locked_mode 锁模式,

       l.oracle_username 登录用户,

       l.os_user_name 登录机器用户名,

       s.machine 机器名,

       s.terminal 终端用户名,

       o.object_name 被锁对象名,

       s.logon_time 登录数据库时间

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#;  

SELECT * FROM V$LOCKED_OBJECT l,V$SESSION S WHERE l.SESSION_ID=S.SID;

--杀掉进程 sid,serial#

alter system kill session '223,10747';

--批量杀死进程

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;