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This article is to share with you about the memory initialization parameters in oracle11g. The editor thinks it is very practical, so I share it with you. I hope you can get something after reading this article. Let's take a look at it.

Several memory initialization parameters in oracle11g

Memory_max_target initialization parameter (advanced, which is only available in oracle11g) sets oracle memory automation management

The memory size of (automatic memory management,AMM). The default value is 0, which means that the new feature is not enabled. The value range of this parameter is

0 to the maximum memory available to the oracle database. This parameter is the maximum value that memory_target can set. This parameter is a static initialization parameter

You need to use scope=spfile when modifying.

Parameter memory_target (advanced), which sets the amount of memory that can be used by the whole system of oracle. Oracle will automatically adjust SGA and memory_target according to the value of SGA.

The value of PGA. This parameter is a dynamic initialization parameter with a default value of 0 and a range of values specified by the 152MB to memory_max_target parameters.

The sga_target initialization parameter (basic), which sets the size of all SGA components. The default value is 0 and the minimum is 64m, and the range of values depends on the operating system.

If this parameter is specified, the following memory pools will automatically resize.

1. Buffer cache (db_cache_size)

2. Shared pool (shared_pool_size)

3. Large pool (large_pool_size)

4. Java pool (java_pool_size)

5. Sterams pool (stream_pool_size)

The parameter specified by sga_target is SGA ASSM (Automatic Shared Memory Management.) The minimum value of the. However, the following SGA components are not affected by ASSM

1 、 log buffer

2. Other buffers, such as keep,recycle, non-standard block buffers

3. Fixd SGA and other internal assignments

The value of sga_target subtracts the total memory of these SGA components that are not affected by ASSM, and the remaining memory is used for ASSM management.

You can use alter system to dynamically modify the size of the sga_target.

After oracle memory automation management is enabled, even if sga_target is set to 0, the management of SGA is still in ASSM mode.

The pga_aggregate_target initialization parameter (basic) sets the PGA size available to all service processes (server processes).

The default value for this parameter is 10m and the larger of 20% of SGA. The value of this parameter ranges from 10m to 4096GB-1. Set the parameter to non-00:00

The value of workarea_size_policy will be set to auto, and the SQL workspace will be resized automatically. If the value

Set to 0, then the value of workarea_size_policy will be set to manual, and the size of the SQL workspace will use * _ area_size

Parameters.

Pga_aggregate_target

Is a dynamic initialization parameter.

However, after oracle memory automation management is enabled, even if the value of pga_aggregate_target is set to 0

It's also auto's.

SQL > show parameter pga_aggregate_target

NAME TYPE VALUE

Pga_aggregate_target big integer 0

SQL > show parameter workarea_size_policy

NAME TYPE VALUE

Workarea_size_policy string AUTO

Note:

Oracle memory management automation management methods are: AMM,ASSM, automatic PGA memory management.

The scope of their management is different from the domain, but I personally think that these methods are better than manual management, because automated management is based on a variety of

Statistics and complex data models to resize the components in the memory of the instance. It is simpler, more timely and more efficient than manual methods.

The above are the memory initialization parameters in oracle11g, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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