Donald_Draper 阅读(121) 评论(0)
Oracle数据库在配置文件中更改最大连接数:http://www.2cto.com/database/201303/192758.html
Oracle日常性能查看 :http://blog.csdn.net/webajax/article/details/8692862
使用命令行手工建立Oracle11gR2数据库:http://www.cnblogs.com/beanbee/archive/2012/09/22/2697689.html
以下命令以管理员system用户测试,普通用户没有相关视图的权限:
当前的数据库连接数
select count(*) from v$process where program=‘Oracle.EXE(SHAD)’;




数据库允许的最大连接数
select value from v$parameter where name ='processes';





当前的session连接数
select count(*) from v$session; 






并发连接数
select count(*) from v$session where status='ACTIVE';





最大连接
show parameter processes;  





查看当前有哪些用户正在使用数据
SELECT osuser, a.username,cpu_time/executions/1000000||'s',b.sql_text,machine
from v$session a, v$sqlarea b
where a.sql_address =b.address order by cpu_time/executions desc;





重启数据库
shutdown immediate;
startup;

修改最大连接数:
alter system set processes = 300 scope = spfile; 


在修改数据库配置之前,尽量先备份数据库;
这个谨慎使用:当时我把processes修改的太小,以至于oracle拒绝连接:
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
进程 ID: 0
会话 ID: 0 序列号: 0


查看日志oradim.log:




Fri Feb 24 09:34:21 2017
D:\Oracle11g\app\oracle\product\11.2.0\server\bin\oradim.exe -startup -sid xe -usrpwd *  -log oradim.log -nocheck 0
Fri Feb 24 09:34:33 2017
ORA-00444: background process "GEN0" failed while starting
ORA-00020: maximum number of processes () exceeded


从上面可以看出,最大连接数太小导致启动是吧!

Oracle数据库在配置文件中更改最大连接数:http://www.2cto.com/database/201303/192758.html



最好不要手动通过配置文件修改,因为配置文件是二进制格式的;最好通过命令行修改

oracle数据库启动目录:



初始化配置文件和密码文件等

oracle实例配置目录:


实例配置文件init且全局,SPFILEXE为对应的实例XE的配置文件

创建用户

 create user donald identified by 123456; 


授权用户
 grant connect, resource to donald;



确定共享池中的命中率:(如果ratio1大于1时,需要加大共享池,如果ratio2大于10%时,需要加大共享池SHARED_POOL_SIZE)
select sum(pins) pins,
sum(reloads) reloads,
(sum(reloads) / sum(pins)) * 100 ratio1
from v$librarycache ;


select sum(gets) gets,
sum(getmisses) getmisses,
(sum(getmisses) / sum(gets)) * 100 ratio2
from v$rowcache ;


判断回滚段竞争的SQL语句:(当Ratio大于2时存在回滚段竞争,需要增加更多的回滚段)
select rn.name, rs.GETS, rs.WAITS, (rs.WAITS / rs.GETS) * 100 ratio
from v$rollstat rs, v$rollname rn
where rs.USN = rn.usn ;


判断恢复日志竞争的SQL语句:(immediate_contention或wait_contention的值大于1时存在竞争)
select name,
(t.IMMEDIATE_MISSES /
decode((t.IMMEDIATE_GETS + t.IMMEDIATE_MISSES),0,-1,
(t.IMMEDIATE_GETS + t.IMMEDIATE_MISSES))) * 100 immediate_contention,
(t.MISSES / decode((t.GETS + t.MISSES), 0, -1, (t.GETS + t.MISSES))) * 100 wait_contention
from v$latch t
where name in ('redo copy', 'redo allocation') ;


判断表空间碎片:(如果最大空闲空间占总空间很大比例则可能不存在碎片,如果比例较小,且有许多空闲空间,则可能碎片很多)
select t.tablespace_name,
sum(t.bytes),max(t.bytes),count(*),
max(t.bytes) / sum(t.bytes) radio
from dba_free_space t
group by t.tablespace_name
order by t.tablespace_name ;


确定命中排序域的次数:
select t.NAME, t.VALUE from v$sysstat t where t.NAME like 'sort%';



查询耗资源的进程(top session)
SELECT s.Schemaname Schema_Name,Decode(Sign(48 - Command),
1, To_Char(Command), 'Action Code #' || To_Char(Command)) Action,Status Session_Status, s.Osuser Os_User_Name, s.Sid, p.Spid,s.Serial# Serial_Num, Nvl(s.Username, '[Oracle process]') User_Name,
s.Terminal Terminal, s.Program Program, St.VALUE Criteria_Value
FROM V$sesstat St, V$session s, V$process p
WHERE St.Sid = s.Sid
AND St.Statistic# = To_Number('38')
AND ('ALL' = 'ALL' OR s.Status = 'ALL')
AND p.Addr = s.Paddr
ORDER BY St.VALUE DESC, p.Spid ASC, s.Username ASC, s.Osuser ASC


查看锁(lock)情况
SELECT /*+ RULE */ Ls.Osuser Os_User_Name, Ls.Username User_Name,Decode(Ls.TYPE,
'RW', 'Row wait enqueue lock', 'TM', 'DML enqueue lock','TX', 'Transaction enqueue lock', 'UL', 'User supplied lock') Lock_Type,o.Object_Name OBJECT,Decode(Ls.Lmode,1, NULL, 2, 'Row Share', 3, 'Row Exclusive',
4, 'Share', 5, 'Share Row Exclusive', 6, 'Exclusive',NULL) Lock_Mode,o.Owner,
Ls.Sid, Ls.Serial# Serial_Num, Ls.Id1, Ls.Id2 FROM Sys.Dba_Objects o, 
(SELECT s.Osuser, s.Username, l.TYPE, l.Lmode, s.Sid, s.Serial#, l.Id1,l.Id2 FROM V$session s, V$lock l
WHERE s.Sid = l.Sid) Ls
WHERE o.Object_Id = Ls.Id1
AND o.Owner <> 'SYS'
ORDER BY o.Owner, o.Object_Name;


查看等待(wait)情况
SELECT Ws.CLASS, Ws.COUNT COUNT, SUM(Ss.VALUE) Sum_Value
FROM V$waitstat Ws, V$sysstat Ss
WHERE Ss.NAME IN ('db block gets', 'consistent gets')
GROUP BY Ws.CLASS, Ws.COUNT;

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