Memory Management

Oracle makes use of a dedicated memory area shared by Oracle system processes and shadow processes, as well as private memory areas used by individual shadow processes.

System Global Area (SGA)

The database shared memory area plays a key role in the operation of the Oracle instance. It provides a storage area so that commonly used objects such as database blocks and optimized SQL statements can be cached for use by other processes. It also facilitates the communication between Oracle system processes (for example, sharing locking information). Oracle refers to this shared memory area as the system global area (SGA).