How to modify memory in Oracle database

When you use Oracle database, you will find that performance issues can become a very difficult problem. In this case, you can solve some problems by adjusting the memory allocation. This article describes how to modify memory in an Oracle database.

Before you start making memory modifications, you should know the impact of memory allocation on the operation of Oracle database. Reasonable allocation of memory can improve database performance and response speed. In Oracle Database, memory allocation is divided into system memory and SGA memory.

Here is some overview of system memory and SGA memory:

System memory

• Used for the operating system and other processes
• Many operations The system reserves a lot of memory for Oracle by default, which can be modified in the Oracle database initialization parameters to achieve optimal performance

SGA memory

• Oracle database One of the most important memory pools
• It includes multiple components, such as shared pool, buffer pool, log buffer pool, etc.
• Compared with system memory, SGA memory can be specially optimized for Oracle database

Now let’s discuss how to modify the memory in the Oracle database:

Step 1: Understand the current memory configuration

Use the following SQL command to view the current memory configuration:

show parameter sga_target;
show parameter sga_max_size;

• sga_target: Display the target size of the current SGA
• sga_max_size: Display the maximum size allowed by the current SGA

Step 2: Modify the SGA size

You can modify the size of SGA by modifying the following parameters:

alter system set sga_target=<desired size> scope=both;

• desired size: desired SGA size

You can also modify the maximum size by modifying the following command SGA size:

alter system set sga_max_size=<desired size> scope=both;

If you feel that the SGA size configuration is not enough, you can also modify the shared pool, buffer pool, log buffer pool and other parameters respectively, for example:

alter system set db_cache_size=<desired size> scope=both;
alter system set shared_pool_size=<desired size> scope=both;
alter system set log_buffer=<desired size> scope=both;

Step 3: Restart the database instance

After modifying the memory allocation, you need to restart the database instance for it to take effect. Use the following command to restart the database instance:

shutdown immediate;
startup;

Step 4: Verify whether the memory adjustment takes effect

You can use the following command to verify whether the memory adjustment takes effect:

show parameter sga_target;
show parameter sga_max_size;

• sga_target: Display the target size of the current SGA
• sga_max_size: Display the maximum size allowed by the current SGA

Through the above steps, you can help you modify the memory configuration in the Oracle database, thereby improving Database performance and responsiveness. Although memory configuration can get tricky to set up, carefully tuning the memory configuration can greatly improve your database performance.

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