来历：网海拾贝
------谁正在造访数据库?
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 (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_$transaction;
ZYP_35.98
------查抄哪些包要不乱
COLUMN OWNER FORMAT A10
Select owner, name, type,
source_size code_size parsed_size error_size BYPES
from dba_object_size
where type='PACKAGE BODY' ORDER BY 4 DESC ;
------查抄一个用户拥有哪些表空间的实体信息:
Select tablespace_name, owner, segment_name,segment_type
from dba_segments
where owner-'SyS'
and segment_type_-'ROLLBACK'
order by tablespace_name, owner, segment_name ;
break on owner on segment_name
COLUMN segment_name FORMAT A15
cOLUMN tablespace_name FORMAT A15
COLUMN file_name FORMAT A20
SELECT A.owner, a.segment_name, b.tablespace_name, b.file_name,
sum(a.bytes) bytes
from dba_extents a, dba_data_files b
where a.file_id-b.file_id group by a.owner, a.segment_name,
b.tablespace_name, b.file_name ;
------看内存缓冲区运用服从的指数是命中率HITS:
Hits=Logical_reads/(logical_reads physical_reads)
其中：logical_reads=db_block_gets consistent_reads
select cur.value db, con.value con, phy.value phy,
(cur.value con.value)/cur.value con.value phy.value)*100 HITS
from v$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 >where > ('system undo header', 'system undo block',
'undo header', 'undo block') ;
select sum(value) from v$sysstat where name in
('db block gets', 'consistents gets') ;
若count/sum(value)年夜于1%，则应思索添加ROLLBACK SEGMENT
------查抄有变乱在哪几个回退段中：
COLUMN u FORMAT A15
COLUMN s FORMAT A15
COLUMN s FORMAT A80
select osuser o, username u, segment_name s, sa.sql_text
from v$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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