--查看數據庫最大連接數
select value from v$parameter where name = ‘processes‘;
--更改數據庫連接數
alter system set processes = 3000 scope = spfile;
--查看被鎖的表 
select b.owner,b.object_name,a.session_id,a.locked_mode from v$locked_object a,dba_objects b where b.object_id = a.object_id;
--查看當前活躍線程數
select s.status,s.* from
 
 v$session s  where schemaname=‘數據庫用戶名‘ and machine=‘機器名‘;
select sid,serial#,username,program,machine,status from v$session;
select count(*) from v$session;

--查看sql執行記錄
select * from v$sqltext  where sql_text like ‘%sql語句%‘;

--查詢鎖表語句  
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正在執行的任務
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當前的被鎖對象
SELECT l.session_id sid,  
       s.serial#,  
       l.locked_mode 鎖模式,  
       l.oracle_username 登錄用戶,  
       l.os_user_name 登錄機器用戶名,  
       s.machine 機器名,  
       s.terminal 終端用戶名,  
       o.object_name 被鎖對象名,  
       s.logon_time 登錄數據庫時間  
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;

--殺掉進程 sid,serial#
alter system kill session ‘223,10747‘;

--批量殺死進程
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;

Oracle數據庫鎖表查詢