Database Reference
In-Depth Information
will connect directly to the database without the need of a listener. User processes coming
from the network will use the Oracle listener to establish a connection to the database. The
listener is a program that “listens” for clients to make database connections on a specific
port. The listener then spawns a foreground process and connects the network connection
to that spawned process.
At first glance, it might seem that the user processes are not all that important to backup
and recovery. As you will see, user processes are actually an integral part of backup and
recovery since you have to be able to connect to the database instance with these processes.
You will also ind as you proceed through this topic that you will need the listener up and
running in order to perform certain functions.
Oracle Memory Structures Related to Backup
and Recovery
The principle SGA memory structure to be aware of when it comes to backup and recovery
is the redo log buffer . This is typically a small area of memory that is configured for Oracle
to store redo records in. This is a very transient area of memory and its size can impact the
performance of your database. Although the redo log buffer will not have a direct impact
on backup and recovery, it's still important to be aware of it in the light of any discussion on
backup and recovery.
The Oracle Data Dictionary
The Oracle data dictionary is a critical piece of the backup and recovery landscape. In
the following sections, we will introduce you to the data dictionary. We will then give you
some information on the basic format of the data dictionary so it will be more familiar to
you when you actually use it. Finally, we will provide a list of views that you will find use-
ful during your backup and recovery efforts.
Overview of the Data Dictionary
The data dictionary is a set of views and tables that expose metadata about your Oracle
Database. For example, if you want to know the name of your database, you can look at
the NAME column in a view called V$DATABASE .
The data dictionary is important because it will give you information on the following
critical components of the database:
Tablespaces
Data files
Redo logs
RMAN backup-related information
Database configuration
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