oracle知识

Oracle性能参数—经典常用

[日期：2011-04-29] 来源：Oracle社区  作者：Oracle

0、数据库参数属性
col PROPERTY_NAME format a25
col PROPERTY_VALUE format a30
col DESCRIPTION format a100
select * from database_properties;

select * from v$version;

1、求当前会话的SID，SERIAL#

SELECT Sid, Serial# FROM V$session
WHERE Audsid = Sys_Context('USERENV', 'SESSIONID');
2、查询session的OS进程ID
SELECT p.Spid "OS Thread", b.NAME "Name-User", s.Program, s.Sid, s.Serial#,s.OSUSEr, s.Machine
FROM V$process p, V$session s, V$bgprocess b
WHERE p.Addr = s.Paddr
AND p.Addr = b.Paddr And (s.sid=&1 or p.spid=&1)
UNION ALL
SELECT p.Spid "OS Thread", s.Username "Name-User", s.Program, s.Sid,s.Serial#, s.OSUSEr, s.Machine
FROM V$process p, V$session s
WHERE p.Addr = s.Paddr
And (s.sid=&1 or p.spid=&1)
AND s.Username IS NOT NULL;


3、根据sid查看对应连接正在运行的sql
SELECT /*+ PUSH_SUBQ */ Command_Type, Sql_Text, Sharable_Mem, Persistent_Mem, Runtime_Mem, Sorts,
Version_Count, Loaded_Versions, Open_Versions, Users_Opening, Executions,
Users_Executing, Loads, First_Load_Time, Invalidations, Parse_Calls,
Disk_Reads, Buffer_Gets, Rows_Processed, SYSDATE Start_Time,
SYSDATE Finish_Time, '>' || Address Sql_Address, 'N' Status
FROM V$sqlarea WHERE Address = (SELECT Sql_Address
FROM V$session WHERE Sid = &sid );


4、查找object为哪些进程所用
SELECT p.Spid, s.Sid, s.Serial# Serial_Num, s.Username User_Name,
a.TYPE Object_Type, s.OSUSEr Os_User_Name, a.Owner,
a.OBJECT Object_Name,
Decode(Sign(48 - Command), 1, To_Char(Command), 'Action Code #' || To_Char(Command)) Action,
p.Program Oracle_Process, s.Terminal Terminal, s.Program Program,
s.Status Session_Status
FROM V$session s, V$access a, V$process p
WHERE s.Paddr = p.Addr
AND s.TYPE = 'USER'
AND a.Sid = s.Sid
AND a.OBJECT = '&obj'
ORDER BY s.Username, s.OSUSEr


5、查看有哪些用户连接
SELECT s.OSUSEr Os_User_Name,Decode(Sign(48 - Command),1,To_Char(Command),
'Action Code #' || To_Char(Command)) Action,
p.Program Oracle_Process, Status Session_Status, s.Terminal Terminal,
s.Program Program, s.Username User_Name,
s.Fixed_Table_Sequence Activity_Meter, '' Query, 0 Memory,
0 Max_Memory, 0 Cpu_Usage, s.Sid, s.Serial# Serial_Num
FROM V$session s, V$process p
WHERE s.Paddr = p.Addr
AND s.TYPE = 'USER'
ORDER BY s.Username, s.OSUSEr


6、根据v.sid查看对应连接的资源占用等情况
SELECT n.NAME, v.VALUE, n.CLASS, n.Statistic# FROM V$statname n, V$sesstat v
WHERE v.Sid = &sid
AND v.Statistic# = n.Statistic#
ORDER BY n.CLASS, n.Statistic#


7、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


8、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;

9、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;


10、求process/session的状态
SELECT p.Pid, p.Spid, s.Program, s.Sid, s.Serial#
FROM V$process p, V$session s
WHERE s.Paddr = p.Addr;


11、求谁阻塞了某个session(10g)
SELECT Sid, Username, Event, Blocking_Session, Seconds_In_Wait, Wait_Time
FROM V$session
WHERE State IN ('WAITING')
AND Wait_Class != 'Idle';


12、查会话的阻塞
col user_name format a32
SELECT /*+ rule */ Lpad(' ', Decode(l.Xidusn, 0, 3, 0)) || l.Oracle_Username User_Name,
o.Owner, o.Object_Name, s.Sid, s.Serial#
FROM V$locked_Object l, Dba_Objects o, V$session s
WHERE l.Object_Id = o.Object_Id
AND l.Session_Id = s.Sid
ORDER BY o.Object_Id, Xidusn DESC;
col username format a15
col lock_level format a8
col owner format a18
col object_name format a32
SELECT /*+ rule */ s.Username,Decode(l.TYPE, 'tm', 'table lock', 'tx', 'row lock', NULL) Lock_Level,
o.Owner, o.Object_Name, s.Sid, s.Serial#
FROM V$session s, V$lock l, Dba_Objects o
WHERE l.Sid = s.Sid
AND l.Id1 = o.Object_Id(+)
AND s.Username IS NOT NULL;


13、求等待的事件及会话信息/求会话的等待及会话信息
SELECT Se.Sid, s.Username, Se.Event, Se.Total_Waits, Se.Time_Waited,Se.Average_Wait
FROM V$session s, V$session_Event Se
WHERE s.Username IS NOT NULL
AND Se.Sid = s.Sid
AND s.Status = 'ACTIVE'
AND Se.Event NOT LIKE '%SQL*Net%'
ORDER BY s.Username;
SELECT s.Sid, s.Username, Sw.Event, Sw.Wait_Time, Sw.State,Sw.Seconds_In_Wait
FROM V$session s, V$session_Wait Sw
WHERE s.Username IS NOT NULL
AND Sw.Sid = s.Sid
AND Sw.Event NOT LIKE '%SQL*Net%'
ORDER BY s.Username;


14、求会话等待的file_id/block_id
col event format a24
col p1text format a12
col p2text format a12
col p3text format a12
SELECT Sid, Event, P1text, P1, P2text, P2, P3text, P3
FROM V$session_Wait
WHERE Event NOT LIKE '%SQL%'
AND Event NOT LIKE '%rdbms%'
AND Event NOT LIKE '%mon%'
ORDER BY Event;
SELECT NAME, Wait_Time
FROM V$latch l
WHERE EXISTS (SELECT 1
FROM (SELECT Sid, Event, P1text, P1, P2text, P2, P3text, P3
FROM V$session_Wait
WHERE Event NOT LIKE '%SQL%'
AND Event NOT LIKE '%rdbms%'
AND Event NOT LIKE '%mon%') x
WHERE x.P1 = l.Latch#);


15、求会话等待的对象
col owner format a18
col segment_name format a32
col segment_type format a32
SELECT Owner, Segment_Name, Segment_Type
FROM Dba_Extents
WHERE File_Id = &File_Id
AND &Block_Id BETWEEN Block_Id AND Block_Id + Blocks - 1;


16、求出某个进程，并对它进行跟踪
SELECT s.Sid, s.Serial#
FROM V$session s, V$process p
WHERE s.Paddr = p.Addr
AND p.Spid = &1;
Exec Dbms_System.Set_Sql_Trace_In_Session(&1, &2, TRUE);
Exec Dbms_System.Set_Sql_Trace_In_Session(&1, &2, FALSE);


17、求当前session的跟踪文件
SELECT P1.VALUE || '/' || P2.VALUE || '_ora_' || p.Spid || '.ora' Filename
FROM V$process p, V$session s, V$parameter P1, V$parameter P2
WHERE P1.NAME = 'user_dump_dest'
AND P2.NAME = 'instance_name'
AND p.Addr = s.Paddr
AND s.Audsid = Userenv('SESSIONID')
AND p.Background IS NULL
AND Instr(p.Program, 'CJQ') = 0;


18、求出锁定的对象
SELECT Do.Object_Name, Session_Id, Process, Locked_Mode
FROM V$locked_Object Lo, Dba_Objects Do
WHERE Lo.Object_Id = Do.Object_Id;

19、DB_Cache建议
SELECT size_for_estimate, buffers_for_estimate, estd_physical_read_factor, estd_physical_reads
FROM V$DB_CACHE_ADVICE
WHERE name = 'DEFAULT'
AND block_size = (SELECT value FROM V$PARAMETER WHERE name = 'db_block_size')
AND advice_status = 'ON';

20、查看各项SGA相关参数：SGA，SGASTAT
select substr(name,1,10) name,substr(value,1,10) value
from v$parameter where name = 'log_buffer';

select * from v$sgastat ;

select * from v$sga;

show parameters area_size   #查看 各项区域内存参数， 其中sort_area为排序参数用；

各项视图建议参数值：V$DB_CACHE_ADVICE、V$SHARED_POOL_ADVICE），关于PGA
也有相关视图V$PGA_TARGET_ADVICE 等。

21、内存使用锁定在物理内存：
AIX 5L（AIX 4.3.3 以上）
logon aix as root
cd /usr/samples/kernel
./vmtune (信息如下) v_pingshm已经是1
./vmtune -S 1
然后oracle用户修改initSID.ora 中 lock_sga = true
重新启动数据库

HP UNIX
Root身份登陆
Create the file "/etc/privgroup": vi /etc/privgroup
Add line "dba MLOCK" to file
As root, run the command "/etc/setprivgrp -f /etc/privgroup":
$/etc/setprivgrp -f /etc/privgroup
oracle用户修改initSID.ora中lock_sga=true
重新启动数据库

SOLARIS (solaris2.6以上)
8i版本以上数据库默认使用隐藏参数 use_ism = true ，自动锁定SGA于内存中,不用设置
lock_sga, 如果设置 lock_sga =true 使用非 root 用户启动数据库将返回错误。

WINDOWS （作用不大）
不能设置lock_sga=true,可以通过设置pre_page_sga=true,使得数据库启动的时候就把所有内
存页装载，这样可能起到一定的作用。

22、内存参数调整
数据缓冲区命中率
select value from v$sysstat where name ='physical reads';

select value from v$sysstat where name ='physical reads direct';

select value from v$sysstat where name ='physical reads direct (lob)';

select value from v$sysstat where name ='consistent gets';

select value from v$sysstat where name = 'db block gets';

这里命中率的计算应该是
令 x = physical reads direct + physical reads direct (lob)
命中率 =100 - ( physical reads - x) / (consistent gets + db block gets - x)*100
通常如果发现命中率低于90%,则应该调整应用可可以考虑是否增大数据缓冲区；

共享池的命中率
select sum(pinhits)/sum(pins)*100 "hit radio" from v$librarycache;

假如共享池的命中率低于95%,就要考虑调整应用（通常是没使用bind var ）或者增加内存；

关于排序部分
select name,value from v$sysstat where name like '%sort%';

假如我们发现sorts (disk)/ (sorts (memory)+ sorts (disk))的比例过高，则通常意味着
sort_area_size 部分内存较小，可考虑调整相应的参数。

关于log_buffer
select name,value from v$sysstat
where name in('redo entries','redo buffer allocation retries');

假如 redo buffer allocation retries/ redo entries 的比例超过1%我们就可以考虑增大log_buffer