经常有人问到如何在Unix下确定进程消耗的内存资源，以及为何Top工具的显示非常高。
有人说Top的输出不精确，这种说法是不确切的。实际上是Top输出显示的Oracle进程内存使用，包含了SGA部分。这也是SGA的意义所在。
SGA可以被共享，可以被所有进程所访问，在进程的寻址空间里就包含了SGA的大小。
至于如何更为精确的确定进程的内存消耗，本文简要介绍如下（在QuickIO下，你可能无法看到本文描述情况）：
1.系统平台及数据库版本
>
> $ uname -a
> SunOS billing 5.8 Generic_108528-23 sun4u sparc SUNW,Ultra-4
>
> Sun Microsystems Inc. SunOS 5.8 Generic Patch October 2001
> $ sqlplus "/ as sysdba"
>
> SQL*Plus: Release 9.2.0.4.0 - Production on Sun Nov 28 10:48:00 2004
>
> Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
>
>
> Connected to:
> Oracle9i Enterprise Edition Release 9.2.0.4.0 - 64bit Production
> With the Partitioning, OLAP and Oracle Data Mining options
> JServer Release 9.2.0.4.0 - Production
>
> SQL> select * from v$version;
>
> BANNER
> ----------------------------------------------------------------
> Oracle9i Enterprise Edition Release 9.2.0.4.0 - 64bit Production
> PL/SQL Release 9.2.0.4.0 - Production
> CORE 9.2.0.3.0 Production
> TNS for Solaris: Version 9.2.0.4.0 - Production
> NLSRTL Version 9.2.0.4.0 - Production
>
> SQL> show sga
>
> Total System Global Area 253200688 bytes
> Fixed Size 731440 bytes
> Variable Size 167772160 bytes
> Database Buffers 83886080 bytes
> Redo Buffers 811008 bytes
> SQL> exit
> Disconnected from Oracle9i Enterprise Edition Release 9.2.0.4.0 - 64bit Production
> With the Partitioning, OLAP and Oracle Data Mining options
> JServer Release 9.2.0.4.0 - Production
>
>
>