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ORACLE应用经历

2020年2月13日 - www.2138.com

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
dwhere 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.osuserfrom
v$session a,audit_actions b where a.command=b.actionAnd
username=&1;——谁被锁住?Select
a.sid,a.serial#,a.username,A.LOCKWAIT,a.status,a.program,b.namefrom
v$session a,audit_actions b where a.command=b.actionAND LOCKWAIT IS NOT
NULL;——谁在锁表?Select
a.sid,a.serial#,a.username,A.LOCKWAIT,a.status,a.program,b.namefrom
v$session a,audit_ORACLE应用经历。actions b where a.command=b.actionAND STATUS=ACTIVE;

Select sid, serial#, object_name, row_wait_block#,
row_wait_row#, row_wait_file# from all_objects, v$sessionwhere
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
s1where 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 A10Select owner, name, type,
source_size+code_size+parsed_size+error_size BYPES from
dba_object_sizewhere 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_segmentswhere owner-SyS and
segment_type_-ROLLBACKorder by tablespace_name, owner, segment_name
;

break on owner on segment_nameCOLUMN segment_name FORMAT A15cOLUMN
tablespace_name FORMAT A15COLUMN file_name FORMAT A20SELECT A.owner,
a.segment_name, b.tablespace_name, b.file_name, sum(a.bytes) bytes
from dba_extents a, dba_data_files bwhere 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

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 phywhere 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$waitstatwhere 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 A15COLUMN s FORMAT
A15COLUMN s FORMAT A80select osuser o, username u, segment_name s,
sa.sql_text from v$session s, v$transaction t, dba_rollback_segs r,
v$sqlarea sawhere s.taddr=t.addr and t.sidusn=r.segmant_id(+) and
s.sql_address=sa.address(+) ;<

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