1.查找当前表级锁的SQL如下：

select sess.sid, sess.serial#, lo.oracle_username, lo.os_user_name, ao.object_name, lo.locked_mode from v$locked_object lo, dba_objects ao, v$session sess

where ao.object_id = lo.object_id and lo.session_id = sess.sid;

简化如下：

select sess.sid, sess.serial# from v$locked_object lo, dba_objects ao, v$session sess where ao.object_id = lo.object_id and lo.session_id = sess.sid;

2.杀掉锁表进程：杀完锁表会话logout

alter system kill session '267,6031';  (填写上一个sql查询出的sid，serial#)

3.RAC环境中锁查找：

SELECT inst_id,DECODE(request,0,'Holder: ','Waiter: ')||sid sess,

id1, id2, lmode, request, type,block,ctime

FROM GV$LOCK

WHERE (id1, id2, type) IN

(SELECT id1, id2, type FROM GV$LOCK WHERE request>0)

ORDER BY id1, request;

4.监控当前数据库谁在运行什么SQL语句

col osuser for a20;

col username for a20;

col sql_text for a20;

select osuser, username, sql_text

from  v$session a, v$sqltext b

where  a.sql_address =b.address order by address, piece;

5.找使用CPU多的用户session

col prog for a10;

col terminal for a10;

select a.sid,spid,status,substr(a.program,1,40) prog, a.terminal,osuser,value/60/100 value

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

where  c.statistic#=12 and

c.sid=a.sid and

a.paddr=b.addr

order by value desc;

6.查看死锁信息

SELECT (SELECT username

FROM v$session

WHERE SID = a.SID) blocker, a.SID, 'is blocking',

(SELECT username

FROM v$session

WHERE SID = b.SID) blockee, b.SID

FROM v$lock a, v$lock b

WHERE a.BLOCK = 1 AND b.request > 0 AND a.id1 = b.id1 AND a.id2 = b.id2;

7.具有最高等待的对象

SELECT   o.OWNER,o.object_name, o.object_type, a.event,

SUM (a.wait_time + a.time_waited) total_wait_time

FROM v$active_session_history a, dba_objects o

WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE

AND a.current_obj# = o.object_id

GROUP BY o.OWNER,o.object_name, o.object_type, a.event

ORDER BY total_wait_time DESC;

SELECT   a.session_id, s.osuser, s.machine, s.program, o.owner, o.object_name,

o.object_type, a.event,

SUM (a.wait_time + a.time_waited) total_wait_time

FROM v$active_session_history a, dba_objects o, v$session s

WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE

AND a.current_obj# = o.object_id

AND a.session_id = s.SID

GROUP BY o.owner,

o.object_name,

o.object_type,

a.event,

a.session_id,

s.program,

s.machine,

s.osuser

ORDER BY total_wait_time DESC;

8.查询当前连接会话数

select s.value,s.sid,a.username

from

v$sesstat S,v$statname N,v$session A

where

n.statistic#=s.statistic# and

name='session pga memory'

and s.sid=a.sid

order by s.value;

9.等待最多的用户

SELECT   s.SID, s.username, SUM (a.wait_time + a.time_waited) total_wait_time

FROM v$active_session_history a, v$session s

WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE

GROUP BY s.SID, s.username

ORDER BY total_wait_time DESC;

10.等待最多的SQL

SELECT   a.program, a.session_id, a.user_id, d.username, s.sql_text,

SUM (a.wait_time + a.time_waited) total_wait_time

FROM v$active_session_history a, v$sqlarea s, dba_users d

WHERE a.sample_time BETWEEN SYSDATE - 30 / 2880 AND SYSDATE

AND a.sql_id = s.sql_id

AND a.user_id = d.user_id

GROUP BY a.program, a.session_id, a.user_id, s.sql_text, d.username;

11.查看消耗资源最多的SQL

SELECT hash_value, executions, buffer_gets, disk_reads, parse_calls

FROM V$SQLAREA

WHERE buffer_gets > 10000000 OR disk_reads > 1000000

ORDER BY buffer_gets + 100 * disk_reads DESC;

12.查看某条SQL语句的资源消耗

SELECT hash_value, buffer_gets, disk_reads, executions, parse_calls

FROM V$SQLAREA

WHERE hash_Value = 228801498 AND address = hextoraw('CBD8E4B0');

13.查询会话执行的实际SQL

SELECT   a.SID, a.username, s.sql_text

FROM v$session a, v$sqltext s

WHERE a.sql_address = s.address

AND a.sql_hash_value = s.hash_value

AND a.status = 'ACTIVE'

ORDER BY a.username, a.SID, s.piece;

14.显示正在等待锁的所有会话

SELECT * FROM DBA_WAITERS;

原文链接：http://www.cnblogs.com/askjacklin/archive/2012/06/04/2534571.html