欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  数据库

Oracle操作Session的方法

程序员文章站 2022-06-13 15:45:16
...

1.如何查看session级的等待事件? 当我们对数据库的性能进行调整时,一个最重要的参考指标就是系统等待事 件。$system_event,v$session_event,v$session_wait这三个视图里记录的就是系统级和session级的等待 事件,通过查询这些视图你可以发现数据库的一些操

1.如何查看session级的等待事件?

当我们对数据库的性能进行调整时,一个最重要的参考指标就是系统等待事 件。$system_event,v$session_event,v$session_wait这三个视图里记录的就是系统级和session级的等待 事件,通过查询这些视图你可以发现数据库的一些操作到底在等待什么?是磁盘I/O,缓冲区忙,还是插锁等等。

通过如下sql你可以查询你的每个应用程序到底在等待什么,从而针对这些信息对数据库的性能进行调整。
Select s.username,s.program,s.status,se.event,se.total_waits,se.total_timeouts,se.time_waited,se.average_wait
from v$session s, v$session_event se
Where s.sid=se.sid And se.event not like 'SQl*Net%' And s.status ='ACTIVE' And s.username is not null

2.oracle中查询被锁的表并释放session
SELECT A.OWNER,A.OBJECT_NAME,B.XIDUSN,B.XIDSLOT,B.XIDSQN,B.SESSION_ID,B.ORACLE_USERNAME, B.OS_USER_NAME,B.PROCESS, B.LOCKED_MODE, C.MACHINE,C.STATUS,C.SERVER,C.SID,C.SERIAL#,C.PROGRAM
FROM ALL_OBJECTS A,V$LOCKED_OBJECT B,SYS.GV_$SESSION C
WHERE ( A.OBJECT_ID = B.OBJECT_ID ) AND (B.PROCESS = C.PROCESS ) ORDER BY 1,2

释放session Sql:
alter system kill session 'sid, serial#'
alter system kill session '379, 21132'
alter system kill session '374, 6938'

3.查看占用系统io较大的session
SELECT se.sid,se.serial#,pr.SPID,se.username,se.status,se.terminal,se.program,se.MODULE,se.sql_address,st.event,st.p1text,si.physical_reads,si.block_changes
FROM v$session se, v$session_wait st,v$sess_io si,v$process pr
WHERE st.sid=se.sid  AND st.sid=si.sid AND se.PADDR=pr.ADDR AND se.sid>6 AND st.wait_time=0 AND st.event NOT LIKE '%SQL%' ORDER BY physical_reads DESC

4.找出耗cpu较多的session
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

5.查询session被锁的sql可以用一下语句

select sys.v_$session.osuser,sys.v_$session.machine,v$lock.sid,

  sys.v_$session.serial#,

  decode(v$lock.type,

  'MR', 'Media Recovery',

  'RT','Redo Thread',

  'UN','User Name',

  'TX', 'Transaction',

  'TM', 'DML',

  'UL', 'PL/SQL User Lock',

  'DX', 'Distributed Xaction',

  'CF', 'Control File',

  'IS', 'Instance State',

  'FS', 'File Set',

  'IR', 'Instance Recovery',

  'ST', 'Disk Space Transaction',

  'TS', 'Temp Segment',

  'IV', 'Library Cache Invalida-tion',

  'LS', 'Log Start or Switch',

  'RW', 'Row Wait',

  'SQ', 'Sequence Number',

  'TE', 'Extend Table',

  'TT', 'Temp Table',

  'Unknown') LockType,

  rtrim(object_type) || ' ' || rtrim(owner) || '.' || object_name object_name,

  decode(lmode, 0, 'None',

  1, 'Null',

  2, 'Row-S',

  3, 'Row-X',

  4, 'Share',

  5, 'S/Row-X',

  6, 'Exclusive', 'Unknown') LockMode,

  decode(request, 0, 'None',

  1, 'Null',

  2, 'Row-S',

  3, 'Row-X',

  4, 'Share',

  5, 'S/Row-X',

  6, 'Exclusive', 'Unknown') RequestMode,

  ctime, block b

  from v$lock, all_objects, sys.v_$session

  where v$Lock.sid > 6

  and sys.v_$session.sid = v$lock.sid

  and v$lock.id1 = all_objects.object_id;