ORACLE应用经验(2)

正在看的ORACLE教程是:ORACLE应用经验(2)。 ------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$session a,audit_actions b
where a.command=b.action
And username=&1;
------谁被锁住?
Select a.sid,A.LOCKWAIT,b.name
from v$session a,audit_actions b
where a.command=b.action
AND LOCKWAIT IS NOT NULL;
------谁在锁表?
Select a.sid,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#=objectid and type=USER
and lockwait is not null ;

Select sl.username,sl.sid,sl.serial#
from v$lock l1,v$session s1
where exists (select 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) ;

select count() from v$session;
select count() from sys.v_$process;
select 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 segmenttype-ROLLBACK
order by tablespace_name,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,
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

select 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?
select class,count from v$waitstat
where class in
(system undo header,system undo block,
undo header,undo block) ;

select 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
select 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(+) ;<

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