ORACLE应用经验(2)

文章作者 100test 发表时间 2008:04:15 15:59:14
来源 100Test.Com百考试题网

------谁正在访问数据库?

Select c.sid, c.serial#,c.username,a.object_id,b.object_name,

c.program,c.status,d.name,c.osuser     

from v$Locked_object a,

     All_objects b,

     v$session c,

     audit_actions d

where a.object_id=b.object_id

     and a.session_id =c.sid( )

     and c.command=d.action.



alter system kill session &.1,&.2.

     

Select a.sid,a.serial#,a.username,a.status,a.program,b.name,a.osuser

from v$session a,audit_actions b 

where a.command=b.action

And  username=&.1.

------谁被锁住?

Select a.sid,a.serial#,a.username,A.LOCKWAIT,a.status,a.program,b.name

from v$session a,audit_actions b 

where a.command=b.action

AND LOCKWAIT IS NOT NULL.

------谁在锁表?

Select a.sid,a.serial#,a.username,A.LOCKWAIT,a.status,a.program,b.name

from v$session a,audit_actions b 

where a.command=b.action

AND STATUS=ACTIVE.



Select sid, serial#, object_name, row_wait_block#,

       row_wait_row#, row_wait_file#

  from all_objects, v$session

 where row_wait_obj#=object_id and type=USER

       and lockwait is not null .



Select sl.username, sl.sid, sl.serial#

  from v_$lock l1, v$session s1

 where exists (0select * from v_$lock l2, v$session s2

                where l2.sid=s2.sid and l2.id1=l1

                  and s2.lockwait=l2.kaddr

                  and request=0

                  and l1.sid=s1.sid) .



0select count(*) from v$session.

0select count(*) from sys.v_$process.

0select count(*) from sys.v_$transaction.



 ZYP_35.98



------查看哪些包要固定

COLUMN OWNER FORMAT A10

Select owner, name, type,

       source_size code_size parsed_size error_size BYPES

  from dba_object_size

 where type=PACKAGE BODY ORDER BY 4 DESC .



------查看一个用户拥有哪些表空间的实体信息:

Select tablespace_name, owner, segment_name,segment_type

  from dba_segments

 where owner-SyS

       and segment_type_-ROLLBACK

 order by tablespace_name, owner, segment_name .



break on owner on segment_name

COLUMN segment_name FORMAT A15

cOLUMN tablespace_name FORMAT A15

COLUMN file_name FORMAT A20

SELECT A.owner, a.segment_name, b.tablespace_name, b.file_name,

       sum(a.bytes) bytes

  from dba_extents a, dba_data_files b

 where a.file_id-b.file_id group by a.owner, a.segment_name,

       b.tablespace_name, b.file_name .



------看内存缓冲区使用效率的指数是命中率HITS:

      Hits=Logical_reads/(logical_reads physical_reads)

其中：logical_reads=db_block_gets consistent_reads



0select cur.value db, con.value con, phy.value phy,

       (cur.value con.value)/cur.value con.value phy.value)*100 HITS

  from v$sysstat cur, v$sysstat con, v$sysstat phy

 where CUR.NAME=db block gets AND

       CON.NAME=consistent gets AND

       PHY.NAME=physical reads .



------如何检测ROLLBACK SEGMENT竞争?

0select class, count from v$waitstat

 where class in

       (system undo header, system undo block,

        undo header, undo block) .



0select sum(value) from v$sysstat where name in

       (db block gets, consistents gets) .



    若count/sum(value)大于1%，则应考虑增加ROLLBACK SEGMENT



------查看有事务在哪几个回退段中：

COLUMN u FORMAT A15

COLUMN s FORMAT A15

COLUMN s FORMAT A80

0select osuser o, username u, segment_name s, sa.sql_text

  from v$session s, v$transaction t, dba_rollback_segs r, v$sqlarea sa

 where s.taddr=t.addr and t.sidusn=r.segmant_id( )

   and s.sql_address=sa.address( ) .