17 Views Relevant to Oracle Data Guard

This chapter describes the views that are especially useful when monitoring a Data Guard environment. The view described in this chapter are a subset of the views that are available for Oracle databases.

Table 17-1 describes the views and indicates if a view applies to physical standby databases, logical standby databases, snapshot standby databases, or primary databases. See Oracle Database Reference for complete information about views.

Table 17-1 Views That Are Pertinent to Data Guard Configurations

View Database Description

DBA_LOGSTDBY_EVENTS

Logical only

Contains information about the activity of a logical standby database. It can be used to determine the cause of failures that occur when SQL Apply is applying redo to a logical standby database.

DBA_LOGSTDBY_HISTORY

Logical only

Displays the history of switchovers and failovers for logical standby databases in a Data Guard configuration. It does this by showing the complete sequence of redo log streams processed or created on the local system, across all role transitions. (After a role transition, a new log stream is started and the log stream sequence number is incremented by the new primary database.)

DBA_LOGSTDBY_LOG

Logical only

Shows the log files registered for logical standby databases.

DBA_LOGSTDBY_NOT_UNIQUE

Logical only

Identifies tables that have no primary and no non-null unique indexes.

DBA_LOGSTDBY_PARAMETERS

Logical only

Contains the list of parameters used by SQL Apply.

DBA_LOGSTDBY_SKIP

Logical only

Lists the tables that will be skipped by SQL Apply.

DBA_LOGSTDBY_SKIP_TRANSACTION

Logical only

Lists the skip settings chosen.

DBA_LOGSTDBY_UNSUPPORTED

Logical only

Identifies the schemas and tables (and columns in those tables) that contain unsupported data types. Use this view when you are preparing to create a logical standby database.

V$ARCHIVE_DEST

Primary, physical, snapshot, and logical

Describes all of the destinations in the Data Guard configuration, including each destination's current value, mode, and status.

Note: The information in this view does not persist across an instance shutdown.

V$ARCHIVE_DEST_STATUS

Primary, physical, snapshot, and logical

Displays runtime and configuration information for the archived redo log destinations.

Note: The information in this view does not persist across an instance shutdown.

V$ARCHIVE_GAP

Physical, snapshot, and logical

Displays information to help you identify a gap in the archived redo log files.

V$ARCHIVED_LOG

Primary, physical, snapshot, and logical

Displays archive redo log information from the control file, including names of the archived redo log files.

V$DATABASE

Primary, physical, snapshot, and logical

Provides database information from the control file. Includes information about fast-start failover (available only with the Data Guard broker).

V$DATABASE_INCARNATION

Primary, physical, snapshot, and logical

Displays information about all database incarnations. Oracle Database creates a new incarnation whenever a database is opened with the RESETLOGS option. Records about the current and the previous incarnation are also contained in the V$DATABASE view.

V$DATAFILE

Primary, physical, snapshot, and logical

Provides datafile information from the control file.

V$DATAGUARD_CONFIG

Primary, physical, snapshot, and logical

Lists the unique database names defined with the DB_UNIQUE_NAME and LOG_ARCHIVE_CONFIG initialization parameters.

V$DATAGUARD_STATS

Primary, physical, snapshot, and logical

Displays various Data Guard statistics, including apply lag and transport lag. This view can be queried on any instance of a standby database. No rows are returned if queried on a primary database. See also Section 8.1.2 for an example and more information.

V$DATAGUARD_STATUS

Primary, physical, snapshot, and logical

Displays and records events that would typically be triggered by any message to the alert log or server process trace files.

V$FS_FAILOVER_STATS

Primary

Displays statistics about fast-start failover occurring on the system.

V$LOG

Primary, physical, snapshot, and logical

Contains log file information from the online redo log files.

V$LOGFILE

Primary, physical, snapshot, and logical

Contains information about the online redo log files and standby redo log files.

V$LOG_HISTORY

Primary, physical, snapshot, and logical

Contains log history information from the control file.

V$LOGSTDBY_PROCESS

Logical only

Provides dynamic information about what is happening with SQL Apply. This view is very helpful when you are diagnosing performance problems during SQL Apply on the logical standby database, and it can be helpful for other problems.

V$LOGSTDBY_PROGRESS

Logical only

Displays the progress of SQL Apply on the logical standby database.

V$LOGSTDBY_STATE

Logical only

Consolidates information from the V$LOGSTDBY_PROCESS and V$LOGSTDBY_STATS views about the running state of SQL Apply and the logical standby database.

V$LOGSTDBY_STATS

Logical only

Displays LogMiner statistics, current state, and status information for a logical standby database during SQL Apply. If SQL Apply is not running, the values for the statistics are cleared.

V$LOGSTDBY_TRANSACTION

Logical only

Displays information about all active transactions being processed by SQL Apply on the logical standby database.

V$MANAGED_STANDBY

Physical and snapshot

Displays current status information for Oracle database processes related to physical standby databases.

Note: The information in this view does not persist across an instance shutdown.

V$REDO_DEST_RESP_HISTOGRAM

Primary

Contains the response time information for destinations that are configured for SYNC transport.

Note: The information in this view does not persist across an instance shutdown.

V$STANDBY_EVENT_HISTOGRAM

Physical

Contains a histogram of apply lag values for the physical standby. An entry is made in the corresponding apply lag bucket by the Redo Apply process every second. (This view returns rows only on a physical standby database that has been open in real-time query mode.)

Note: The information in this view does not persist across an instance shutdown.

V$STANDBY_LOG

Physical, snapshot, and logical

Contains log file information from the standby redo log files.