[bbk5189]第71集 第8章 -性能维护 02

Managing Memory Commpents

Automatic Memory Management(AMM)

-Enable you to specifiy total memory allocated to instance (including both SGA and PGA)

指定MEMORY TARGET参数后，Oracle会自动分配内存.实现此特性的前提就是Oracle所在的操作系统支持自动释放内存.

ASSM(自动共享内存管理，共享内存实际上就是SGA)

如何启动自动内存管理?

1、通过OEM，设置Enable属性

2、手工方式修改MEMORY_TARGET参数

SQL> show parameter memory_target;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
memory_target                        big integer 3120M

如何实现自动共享内存管理?

1、通过OEM，设置其Enable属性

2、手工命令行方式，修改SGA_TARGET属性

SQL> show parameter sga_target;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
sga_target                           big integer 0

Managing Memory Conponents

• Automatic Memory Management(AMM)
  • -Enable you to specify total memory allocated to instance (Including both SGA and PGA)
• Automatic Shared Memory Management(ASMM)
  • -Enables you to specify total SGA memory through one initialization parameter
  • -Enables the oracle server to manage the amount of memory allocated to the shared pool,java pool,buffer cache,steams pool,and large pool
• Manually setting shared memory management
• Sizes the components through multiple individual initialization parameters
• -Uses the appropriate Memory Advisor to make recommendations