Automatic memory
management initialization parameters can be set through Oracle Enterprise Manager.
The background processes interact with the operating system and each other to manage
the memory structures for the instance. These processes also manage the actual
database on disk and perform general housekeeping for the instance.
Figure 2-8 illustrates the memory structures and background processes discussed in
the following section.
Figure 2-8. An Oracle instance
Database Buffer Cache Shared Pool
Redo Log
Buffer
SGA
SMON PMON RECO
DBWR CKPT LGWR ARCH
Datafiles Control Files Redo Logs
50 | Chapter 2: Oracle Architecture
Additional background processes may exist when you use certain other features of
the database: for example, shared servers (formerly the Multi-Threaded Server or
MTS prior to Oracle9i), or job queues and replication.
Memory Structures for an Instance
As shown in Figure 2-8, the System Global Area is composed of multiple areas.
These include a database buffer cache, a shared pool, and a redo log buffer as shown
in the figure, and also possibly a Java pool, a large pool, and a Streams pool.
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