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The Oracle9i SGA
SGA = System Global Area
Shared memory area
Contains:
- Shared Pool
- Large Pool
- Java Pool
- Buffer Cache
- Redo Log Buffer
Overall size limited by SGA_MAX_SIZE
Notes:
The System Global Area (SGA) is a shared memory area used to hold data that can be used by all users connected to the database. For example, the buffer cache contains cached copies of database file blocks (i.e. table and index data read from files that can be used by all privileged users).
The SGA itself has three main required components - the Database Buffer Cache, the Shared Pool and the Redo Buffer. We will cover these structures and more as we progress through this lesson.
As of Oracle9i, the maximum overall size of the SGA is limited by the initialization parameter SGA_MAX_SIZE.
Also see the Oracle9i Concepts Guide for more information on these memory structures.