What's New in Data Guard?

This section describes the new Data Guard features in Oracle9i release 2 (9.2) and provides pointers to additional information. Information about new features from previous releases is retained to help those users who are upgrading to the current release.

The following sections describe the new features in Data Guard:

• Oracle9i Release 2 (9.2) New Features in Data Guard
• Oracle9i Release 1 (9.0.1) New Features in Data Guard

Oracle9i Release 2 (9.2) New Features in Data Guard

The features and enhancements described in this section were added to Data Guard in Oracle9i release 2 (9.2).

• Logical standby database

  Until now, there has been only the physical standby database implementation, in which the standby database performs either managed recovery or read-only operations. A physical standby database is physically equivalent to the primary database. While redo logs are being applied to a physical standby database, it cannot be opened for reporting, and when the physical standby database is open for reporting, redo logs cannot be applied to it. A logical standby database has the same logical schema as the primary database, but it may have different physical objects, such as additional indexes. With logical standby databases, the database can be available for reporting at the same time you are applying redo logs to it.

• Data protection modes

  The database administrator (DBA) can place the database into one of the following modes:

  • Maximum protection
  • Maximum availability
  • Maximum performance

  These modes replace the guaranteed, instant, rapid, and delayed modes of data protection available in Oracle9i release 1 (9.0.1).

  See Also: Chapter 5, "Log Transport Services" and Chapter 13, "SQL Statements"

• Cascading redo log destinations

  A cascaded redo log destination is a standby database that receives its redo data from another standby database and not from the original primary database. A physical or logical standby database can be set up to send the incoming redo data to other remote destinations in the same manner as the primary database, with up to one level of redirection.

  See Also: Appendix D, "Cascaded Redo Log Destinations"

• Oracle9i Data Guard broker

  The broker now supports:

  • Up to nine physical or logical standby destinations
  • Failover and switchover operations

    See Also: Oracle9i Data Guard Broker

• New keywords for the REMOTE_ARCHIVE_ENABLE initialization parameter include:
  • send
  • receive

    See Also: Section 5.3.2.1, "Setting Permission to Archive Redo Logs"

• New attributes for the LOG_ARCHIVE_DEST_n initialization parameter include:
  • [NO]TEMPLATE

    Defines a directory specification and format for archived redo logs at the standby destination.

  • [NO]NET_TIMEOUT

    Specifies the number of seconds the log writer process will wait for status from the network server of a network operation issued by the log writer process.

  • PARALLEL qualifier to the SYNC attribute

    Indicates if I/O operations to multiple destinations are done in parallel or in series.

    See Also: Chapter 12, "LOG_ARCHIVE_DEST_n Parameter Attributes"

• New syntax added to the ALTER DATABASE statement includes:
  • ACTIVATE [PHYSICAL | LOGICAL] STANDBY DATABASE [SKIP [STANDBY LOGFILE]]
  • COMMIT TO SWITCHOVER TO {PHYSICAL | LOGICAL} {PRIMARY | STANDBY} [[WITH | WITHOUT] SESSION SHUTDOWN [WAIT | NOWAIT]]
  • [NO]FORCE LOGGING
  • RECOVER MANAGED STANDBY DATABASE [FINISH [SKIP [STANDBY LOGFILE] [WAIT | NOWAIT]]
  • RECOVER MANAGED STANDBY DATABASE [THROUGH {ALL | NEXT | LAST} SWITCHOVER]
  • RECOVER MANAGED STANDBY DATABASE [THROUGH ALL ARCHIVELOG | [ THREAD n ] SEQUENCE n ]
  • REGISTER [OR REPLACE] [PHYSICAL | LOGICAL] LOGFILE filespec
  • SET STANDBY DATABASE TO MAXIMIZE {PROTECTION | AVAILABILITY | PERFORMANCE}
  • START LOGICAL STANDBY APPLY
  • {STOP | ABORT} LOGICAL STANDBY APPLY

    See Also: Chapter 13, "SQL Statements"

• New views were added:
  • DBA_LOGSTDBY_EVENTS
  • DBA_LOGSTDBY_LOG
  • DBA_LOGSTDBY_NOT_UNIQUE
  • DBA_LOGSTDBY_PARAMETERS
  • DBA_LOGSTDBY_PROGRESS
  • DBA_LOGSTDBY_SKIP
  • DBA_LOGSTDBY_SKIP_TRANSACTION
  • DBA_LOGSTDBY_UNSUPPORTED
  • V$DATAGUARD_STATUS
  • V$LOGSTDBY
  • V$LOGSTDBY_STATS

    See Also: Chapter 14, "Views"

• New columns were added to existing fixed views:
  • V$ARCHIVE_DEST view:
    • NET_TIMEOUT
    • TYPE
  • V$ARCHIVE_DEST_STATUS view:
    • PROTECTION_MODE
    • SRL
  • V$DATABASE view:
    • GUARD_STATUS
    • SUPPLEMENTAL_LOG_DATA_MIN
    • SUPPLEMENTAL_LOG_DATA_PK
    • SUPPLEMENTAL_LOG_DATA_UI
    • FORCE_LOGGING
    • PROTECTION_LEVEL

      See Also: Chapter 14, "Views"

• Existing columns were renamed in existing fixed views:
  • V$ARCHIVE_DEST view:
    • MANIFEST has been renamed to REGISTER and values have been changed to YES and NO.
    • REGISTER has been renamed to REMOTE_TEMPLATE.
  • V$DATABASE view:
    • STANDBY_MODE has been renamed to PROTECTION_MODE and values MAXIMUM PROTECTED, MAXIMUM AVAILABILITY, RESYNCHRONIZATION, MAXIMUM PERFORMANCE, and UNPROTECTED have been added.

      See Also: Chapter 14, "Views"

• New values were added to existing columns of existing fixed views:
  • TRANSMIT_MODE column of the V$ARCHIVE_DEST view:
    • PARALLELSYNC
    • SYNCHRONOUS
    • ASYNCHRONOUS
  • REMOTE_ARCHIVE column of the V$DATABASE view:
    • send
    • receive

      See Also: Chapter 14, "Views"

• New integer values were added for the LOG_ARCHIVE_TRACE parameter:
  • 1024: RFS physical client tracking
  • 2048: ARCn or RFS heartbeat tracking

    See Also: Section 6.7.3

Oracle9i Release 1 (9.0.1) New Features in Data Guard

The features and enhancements described in this section were added to Data Guard in Oracle9i release 1 (9.0.1).

• Oracle9i Data Guard.

  Oracle8i Standby Database was renamed to Oracle9i Data Guard.

• Oracle9i Data Guard broker.

• No data loss.

• Database switchover.

• Archive gaps are automatically detected and transmitted.

• Add new datafiles to the primary database without having to manually add the corresponding datafile to the standby databases.

• Background managed recovery mode.

• Parallel recovery allows faster recovery on physical standby databases.

• Specify up to 10 archive destinations.

• Incrementally modify individual attributes of the LOG_ARCHIVE_DEST_n initialization parameter.

• Standby redo logs.

• Archiver process (ARCn ) on physical standby databases can archive standby redo logs.

• Archive the current redo log, archive an online redo log based on the SCN (system change number) value when the database is mounted, but not open, or archive an online redo log when a backup control file is being used. In previous releases, a current control file was required.

• New control options: DELAY, DISCONNECT, EXPIRE, FINISH, NEXT, NODELAY

• Support for Standby Databases in Real Application Clusters.

• New archive log repository, which is a standalone standby database.

• Relationship defined between an archived redo log and an archive destination.

• New initialization parameters: REMOTE_ARCHIVE_ENABLE, FAL_CLIENT, FAL_SERVER, STANDBY_FILE_MANAGEMENT, ARCHIVE_LAG_TARGET

• New attributes for the LOG_ARCHIVE_DEST_n initialization parameter include:
  • ARCH | LGWR
  • [NO]AFFIRM
  • [NO]ALTERNATE
  • [NO]DELAY
  • [NO]DEPENDENCY
  • [NO]MAX_FAILURE
  • [NO]QUOTA_SIZE
  • [NO]QUOTA_USED
  • [NO]REGISTER | REGISTER [=location_format]
  • NOREOPEN
  • SYNC | ASYNC

• A new range of values and the ALTERNATE keyword were added to the LOG_ARCHIVE_DEST_STATE_n initialization parameter.

• One to ten destinations (compared with one to five in Oracle8i) must archive successfully before the log writer process (LGWR) can overwrite the online redo logs.

• New tracing levels (128, 256, and 512) have been added to the LOG_ARCHIVE_TRACE initialization parameter.

• New clauses have been added to the ALTER DATABASE statement:
  • ACTIVATE [PHYSICAL] STANDBY DATABASE
[SKIP [STANDBY LOGFILE]]
  • ADD [STANDBY] LOGFILE TO [THREAD integer]
[GROUP integer] filespec
  • ADD [STANDBY] LOGFILE MEMBER 'filename' [REUSE] TO 'logfile-descriptor'
  • COMMIT TO SWITCHOVER TO [PHYSICAL]
{PRIMARY | STANDBY} [[NO]WAIT]
  • REGISTER [PHYSICAL] LOGFILE filespec
  • SET STANDBY DATABASE {PROTECTED | UNPROTECTED}

    Note: In Oracle9i release 2, this syntax was further revised. See the "Oracle9i Release 2 (9.2) New Features in Data Guard" section.

• New keywords were added to the RECOVER MANAGED STANDBY DATABASE clause:
  • NODELAY
  • CANCEL [IMMEDIATE] [NOWAIT]
  • [DISCONNECT [FROM SESSION]]
  • [FINISH [NOWAIT]]
  • [PARALLEL [integer]]
  • NEXT
  • EXPIRE
  • DELAY

    Note: In Oracle9i release 2, this syntax was further revised. See the "Oracle9i Release 2 (9.2) New Features in Data Guard" section.

• New fixed views were added:
  • V$ARCHIVE_DEST_STATUS
  • V$ARCHIVE_GAP
  • V$MANAGED_STANDBY
  • V$STANDBY_LOG

    See Also: Chapter 14, "Views"

• New columns were added to existing fixed views:
  • V$ARCHIVE_DEST view:
    • AFFIRM
    • ALTERNATE
    • ARCHIVER
    • ASYNC_BLOCKS
    • DELAY_MINS
    • DEPENDENCY
    • FAILURE_COUNT
    • LOG_SEQUENCE
    • MANIFEST (This column name was new in Oracle9i release 1; it was changed to REGISTER in Oracle9i release 2.)
    • MAX_FAILURE
    • MOUNTID
    • PROCESS
    • QUOTA_SIZE
    • QUOTA_USED
    • REGISTER (This column name was new in Oracle9i release 1; it was changed to REMOTE_TEMPLATE in Oracle9i release 2.)
    • SCHEDULE
    • TRANSMIT_MODE
    • TYPE
    • New values, ALTERNATE and FULL, have been added to the STATUS column.
  • V$ARCHIVED_LOG view:
    • APPLIED
    • BACKUP_COUNT
    • COMPLETION_TIME
    • CREATOR
    • DELETED
    • DEST_ID
    • DICTIONARY_BEGIN
    • DICTIONARY_END
    • REGISTRAR
    • STANDBY_DEST
    • STATUS
    • END_OF_REDO
    • ARCHIVAL_THREAD#
  • V$LOG view:
    • A new value, INVALIDATED, was added to the STATUS column.
  • V$LOGFILE view:
    • TYPE
  • V$DATABASE view:
    • ACTIVATION#
    • ARCHIVELOG_CHANGE#
    • DATABASE_ROLE
    • REMOTE_ARCHIVE
    • STANDBY_MODE
    • SWITCHOVER_STATUS
  • V$ARCHIVE_DEST_STATUS view:
    • STANDBY_LOGFILE_COUNT
    • STANDBY_LOGFILE_ACTIVE

      Note: In Oracle9i release 2, new values were added and existing columns renamed in the V$DATABASE and V$ARCHIVE_DEST fixed views. See the "Oracle9i Release 2 (9.2) New Features in Data Guard" section.