Chapter 1. Oracle Architecture Components

Terms you'll need to understand:

• Oracle Server

• Oracle database

• Oracle instance

• System Global Area

• Program Global Area

• Log writer

• Database Writer

• Archiver

• Checkpoint

• System Monitor

• Process Monitor

• Extent

• Segment

• Data Block

Concepts you'll need to master:

• Describe the difference between a database and an instance.

• Describe the physical structures associated with the Oracle database.

• Describe the logical structures associated with the Oracle instance.

• Describe the memory structures in an Oracle instance.

• Describe and understand the different processes associated with an Oracle instance.

• Describe what takes place when a user connects to an Oracle instance.

One of the first things that you need to become comfortable with when you plan for this and all the Oracle exams is the architecture of the Oracle server, the instance and the database. After you have a handle on the architecture and its vocabulary, you will have a solid foundation on which to build for this and the other exams. We start our discussion of the Oracle architecture with the broadest category, but the one most often confused by new administrators and experienced DBAs alikethe difference between the database and the instance. Many people use these terms interchangeably, but they are distinct and different.