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有些迷惑 ?????????

原创 Linux操作系统 作者:jacky2000 时间:2004-04-08 13:51:03 0 删除 编辑
今天把 Oracle DBA Fundamentals I 溫習一下 . 發現一個問題 .
PGA 不署與 SGA 的一部分 .
但是 PGA 的
• Sort area:
• Session information:
• Cursor state:
• Stack space:
又可以存在與 SHARED POOL 中 .
If a large pool is created, the structures are stored in the large pool;
otherwise, they are stored in the shared pool.

是不是 "PGA 不署與 SGA 的一部分 ."  不太確切 .

以下是書上的原文 , 希望有高手幫忙解釋一下 .
***********************************************************************
Program Global Area Components
The Program Global Area or Process Global Area (PGA) is a memory region that contains
data and control information for a single server process or a single background process. The
PGA is allocated when a process is created and deallocated when the process is terminated.
In contrast to the SGA, which is shared by several processes, the PGA is an area that is used
by only one process. In a dedicated server configuration, the PGA includes these
components:
• Sort area: Used for any sorts that may be required to process the SQL statement
• Session information: Includes user privileges and performance statistics for the session
• Cursor state: Indicates the stage in the processing of the SQL statements that are
currently used by the session
• Stack space: Contains other session variables
Note: Some of these structures are stored in the SGA when using a shared server
configuration. If using a shared server configuration, it is possible for multiple user processes
to share server processes. If a large pool is created, the structures are stored in the large pool;
otherwise, they are stored in the shared pool.

這是他的課後題 .
2 Which one of the following memory areas is not part of the SGA?
a Database buffer cache
b PGA
c Redo log buffer cache
d Shared Pool
達案: B

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