Windows 32bit OS上物理内存限制以及ORACLE 10G 在32bit OS的SGA内存分配限制解决方法

今天有个朋友问起32位数据库的SGA 限制的问题,

现在整理如下，仅供参考学习之用。。

重要提示，操作有风险，建议先测试再实施，

原来由于32位操作系统本身的问题，内存只能认到不到4GB，好在微软加了一个什么参数PAE，解决了这个内存限制

在微软网站上看到的各个版本内存的最大扩展情况如下：

Physical Memory Limits: Windows Vista

The following table specifies the limits on physical memory for Windows Vista.

Version Limit in 32-bit Windows/Limit in 64-bit Windows

Windows Vista Ultimate 4 GB/ 128 GB

Windows Vista Enterprise 4 GB/128 GB

Windows Vista Business 4 GB/128 GB

Windows Vista Home Premium 4 GB/16 GB

Windows Vista Home Basic 4 GB/ 8 GB

Windows Vista Starter 1 GB / Not applicable

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Physical Memory Limits: Windows Home Server

Windows Home Server is available only in a 32-bit edition. The physical memory limit is 4 GB.

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Physical Memory Limits: Windows Server 2003

The
following table specifies the limits on physical memory for Windows
Server 2003. Limits over 4 GB for 32-bit Windows assume that PAE is
enabled.

Version Limit in 32-bit Windows /Limit in 64-bit Windows

Windows Server 2003 with Service Pack 2 (SP2), Datacenter Edition 128 GB/2TB

Windows Server 2003 with Service Pack 2 (SP2), Enterprise Edition 64 GB/2 TB

Windows Storage Server 2003, Enterprise Edition 8 GB/ Not applicable

Windows Storage Server 2003 4 GB/ Not applicable

Windows Server 2003 R2 Datacenter Edition

Windows Server 2003 with Service Pack 1 (SP1), Datacenter Edition 128 GB /16 GB with 4GT/ 1 TB

Windows Server 2003 with Service Pack 1 (SP1), Enterprise Edition 64 GB/16 GB with 4GT/1TB

Windows Server 2003 R2 Standard Edition

Windows Server 2003, Standard Edition SP1

Windows Server 2003, Standard Edition SP2 4GB/32GB

Windows Server 2003, Datacenter Edition 128 GB/16 GB with 4GT/512GB

Windows Server 2003, Enterprise Edition 32 GB/16 GB with 4GT/64GB

Windows Small Business Server 2003 4 GB

Not applicable

Windows Compute Cluster Server 2003 Not applicable

32 GB

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Physical Memory Limits: Windows XP

The following table specifies the limits on physical memory for Windows XP.

Version Limit in 32-bit Windows Limit in 64-bit Windows

Windows XP 4 GB

128 GB

Windows XP Starter Edition 512 MB

Not applicable

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Physical Memory Limits: Windows 2000

The following table specifies the limits on physical memory for Windows 2000.

Version Limit in 32-bit Windows

Windows 2000 Professional 4 GB

Windows 2000 Server 4 GB

Windows 2000 Advanced Server 8 GB

Windows 2000 Datacenter Server 32 GB

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OS 是32bit 的，Oracle 数据库 也只能安装32bit 的，这样了就SGA也受到限制，最大不能超过1.7G

看着那大把的内存，但数据库用不上，怪可惜的。。通过下面的方法可以解开内存的限制/

- 在操作系统配置AWE,修改boot.ini文件

右击"我的电脑"，选择"属性"-->高级选项卡，找到“启动与故障恢复”，单击“设置”，然后单击“编辑”，

加/PAE选项，修改后的文件如下：

[boot loader]

timeout=30

default=multi(0)disk(0)rdisk(0)partition(2)WINDOWS

[operating systems]

multi(0)disk(0)rdisk(0)partition(2)WINDOWS="Windows Server 2003, Enterprise" /noexecute=optout /fastdetect /pae

- 通过修改注册表，变成oracle可以使用的内存，

“开始”- “运行” -“regedit"

HKEY_LOCAL_MACHINESOFTWAREORACLEKEY_oracle_home1，

添加新的strings：AWE_WINDOW_MEMORY ，这个值是准备分配给数据库用的最大内存数(以BYTE为单位),例如你想分配3G,那这个值就是

3*1024*1024*1024

- 通过下面方法，修改参数让ORACLE DB能使用上刚分配出来的MEM

Sqlplus "/ as sysdba" R

SQLPLUS>create pfile from spfile;

SQLPLUS>Shutdown immediate

SQLPLUS>exit

- 修改ORACLE pfile

注释掉如下的参数：

sga_max_size

sga_target

DB_CACHE_SIZE

增加如下参数

修改或者添加以下参数

*.db_block_buffers=20000　 #２Ｇ　为例

*.SHARED_POOL_SIZE=400000000 # 400M　为例

*.log_buffer=73000000 # 70M

*.use_indirect_data_buffers=true

sqlplus "/as sysdba"

sql>create spfile from pfile

sql>startup

- 通过以上的方法就可以让内存大大超过１.7GB了

但通过以上的方法修改后，可能在某些平台上会出现ＢＵＧ，建议到ＭＥＴＡＬＩＮＫ查看相关ＮＯＴＥ

参考Ｎotes:

Oracle Database and the Windows NT memory architecture, Technical Bulletin

Doc ID: 46001.1

Oracle Database Server and the Operating System Memory Limitations

Doc ID: 269495.1