Data Guard Broker States & Properties Oracle Database Tips by Donald BurlesonDecember 9, 2015

Oracle Data Guard - States and Properties

These two terms will appear several times in this text; therefore, the definition for each term is listed below:

State

A state defines the condition of a database such as whether the database is open, closed, open for query only, etc. A primary database can be in the ONLINE, LOG-TRANSPORT-OFF or OFFLINE state.  In the LOG-TRANSPORT-OFF state, the primary database will suspend the log transport services to the standby databases. The archiver process will continue to archive to local archiving destinations.

A physical Oracle instance can be in the ONLINE, READ-ONLY, LOG-APPLY-OFF, or OFFLINE state. In the ONLINE state, the physical Oracle instance is in managed recovery mode. Similarly, in the READ-ONLY state, the database is open for query. In the LOG-APPLY-OFF state, the database is mounted in physical standby mode, but the recovery is not started.

Broker States and Properties - Broker states

A logical Oracle instance can be in the ONLINE, LOG-APPLY-OFF or OFFLINE state. In the LOG-APPLY-OFF state, the logical Oracle instance is open for read-only queries. In the OFFLINE state, the broker shuts down the database, stops the managed recovery process and disables the site in the configuration. Both the primary and the standby site have similar behaviour in the OFFLINE state.

Properties

Properties are the atomic level attributes of a database. There are two types of properties: monitorable and configurable. Monitorable properties can only be viewed, but configurable properties can be modified and controls the behaviour of the database.

Preparing to Use Data Guard Broker

Before going into the details of management and administration using Data Guard broker, please read the following pre-requisites and the starting up of Data Guard broker. Set the following parameters in initialization parameter file:

• dg_broker_config_file2='filespec1'

• dg_broker_config_file2='filespec2'

These two parameters specify the location of the broker configuration files. In absence of these parameters, the broker configuration files are created in an operating system dependent location with an operating system dependent file naming convention.