Oracle instance is made up of background processes and the shared memory (SGA). The background processes perform the maintenance tasks that are required to keep the database running. These background processes operate on the allocated shared memory. For example, one of the background process (PMON) is responsible for cleaning up (releasing locks and resources) after abnormally terminated database connections.
There are two types of memory that Oracle instance allocates:
System Global Area (SGA): This is a shared memory area that contains database buffers, shared SQL and PL/SQL, and other control information for the instance.
Process Global Area (PGA): This memory is private to a single process. PGA keeps process-specific information such as Oracle shared resources being used by a process, operating system resources used by the process, and other database session related information.
Oracle Database XE uses Automatic Memory Management (AMM) . This means Oracle Database...