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RAC负载均衡的简单测试(二)

原创 Linux操作系统 作者:yangtingkun 时间:2007-04-12 00:00:00 0 删除 编辑

Rac环境安装完成之后,打算简单测试一下Oracle RAC的负载均衡功能。

这篇继续讨论负载均衡的特性。

RAC负载均衡的简单测试(一):http://yangtingkun.itpub.net/post/468/279433


上一篇的测试中可以看到,当两个实例的负载相当的时候,新连接会平均分配到两个实例上去。

下面看看如果其中一个实例的连接数明显大于另一个实例的情况。增加连接TESTRAC2实例的连接数,这里使用的方法是在racnode2数据库上使用直接连接的方式:

$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:24:23 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:24:28 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:24:33 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:24:37 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:24:44 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:24:48 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:24:54 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 19:25:00 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

输入口令:

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL>

查询目前数据库的连接情况:

SQL> SELECT INST_ID, COUNT(*) FROM GV$SESSION GROUP BY INST_ID;

INST_ID COUNT(*)
---------- ----------
1 31
2 38

下面尝试多次连接,并检查连接的实例:

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac2

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac2

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac2

发现连接到两个实例的概率仍然是一样的。看看连续启动多个连接的情况:

E:>SQLPLUS NDMAIN/NDMAIN@TESTRAC

SQL*Plus: Release 10.2.0.1.0 - Production on 星期四 3 22 19:27:05 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> HOST
Microsoft Windows 2000 [Version 5.00.2195]
(C)
版权所有 1985-2000 Microsoft Corp.

E:>SQLPLUS NDMAIN/NDMAIN@TESTRAC

SQL*Plus: Release 10.2.0.1.0 - Production on 星期四 3 22 19:27:18 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac2

SQL> HOST
Microsoft Windows 2000 [Version 5.00.2195]
(C)
版权所有 1985-2000 Microsoft Corp.

E:>SQLPLUS NDMAIN/NDMAIN@TESTRAC

SQL*Plus: Release 10.2.0.1.0 - Production on 星期四 3 22 19:27:31 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> HOST
Microsoft Windows 2000 [Version 5.00.2195]
(C)
版权所有 1985-2000 Microsoft Corp.

E:>SQLPLUS NDMAIN/NDMAIN@TESTRAC

SQL*Plus: Release 10.2.0.1.0 - Production on 星期四 3 22 19:27:40 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac2

可以看到,结果仍然是50%的概率。难道负载均衡不考虑实例本身的负载,只是对新增连接进行平均分配?

其实并不是这样,关键在于负载均衡的功能是通过LISTENER来实现的。而在上面增加TESTRAC2上的连接数的时候,采用的是本地连接方式,恰恰绕过了LISTENER,对于LISTENER来说,这些新增的会话都是不可见的。因此,得到的结果当然和原来的一致。

下面断开刚才连接的所有会话:

SQL> SELECT INST_ID, COUNT(*) FROM GV$SESSION GROUP BY INST_ID;

INST_ID COUNT(*)
---------- ----------
1 31
2 30

然后以TESTRAC2为服务名,连接到RACTESTRAC2实例上:

$ sqlplus ndmain/ndmain@testrac2

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 21:14:44 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain/ndmain@testrac2

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 21:14:52 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain/ndmain@testrac2

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 21:14:55 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain/ndmain@testrac2

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 21:14:59 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain/ndmain@testrac2

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 21:15:04 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> host
$ sqlplus ndmain/ndmain@testrac2

SQL*Plus: Release 10.2.0.2.0 - Production on 星期四 3 22 21:15:14 2007

Copyright (c) 1982, 2005, Oracle. All Rights Reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL>

再次测试连接实例的情况:

SQL> SELECT INST_ID, COUNT(*) FROM GV$SESSION GROUP BY INST_ID;

INST_ID COUNT(*)
---------- ----------
1 31
2 36

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> CONN NDMAIN/NDMAIN@TESTRAC已连接。
SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> DISC Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options
断开

可以看到,连接时Oracle都会将会话连接到TESTRAC1上。下面看看连续启动多个会话,Oracle如何在实例间分配会话:

E:>SQLPLUS NDMAIN/NDMAIN@TESTRAC

SQL*Plus: Release 10.2.0.1.0 - Production on 星期四 3 22 21:19:41 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> HOST
Microsoft Windows 2000 [Version 5.00.2195]
(C)
版权所有 1985-2000 Microsoft Corp.

E:>SQLPLUS NDMAIN/NDMAIN@TESTRAC

SQL*Plus: Release 10.2.0.1.0 - Production on 星期四 3 22 21:19:59 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL> HOST
Microsoft Windows 2000 [Version 5.00.2195]
(C)
版权所有 1985-2000 Microsoft Corp.

E:>SQLPLUS NDMAIN/NDMAIN@TESTRAC

SQL*Plus: Release 10.2.0.1.0 - Production on 星期四 3 22 21:20:12 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> SELECT INSTANCE_NAME FROM V$INSTANCE;

INSTANCE_NAME
----------------
testrac1

SQL>

根据上面的测试可以看出,Oracle的负载均衡和实例通过LISTENER建立的连接数有关。

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/4227/viewspace-69237/,如需转载,请注明出处,否则将追究法律责任。

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