Oracle 11g already have two releases. Oracle 11g Release 1 (11.1g) and Oracle 11g Release 2(11.2g). In this post I will specify new features available to Oracle data guard 11g separately.
New Features in Oracle Data Guard 11.1 (Applicable to both Redo Apply and SQL Apply)
- The COMPRESSION attribute is used to specify whether redo data is compressed before transmission to a redo transport destination.
- With NET_TIMEOUT attribute it is specified the number of seconds that the LGWR background process will block waiting for a redo transport destination to acknowledge redo data sent to it. If an acknowledgement is not received within NET_TIMEOUT seconds, an error is logged and the redo transport session to that destination is terminated.
- Role transitions happened faster than previous versions.
- Strong authentication for redo transport network sessions.
- Simplified Data Guard management interface by deprecation of redundant SQL clauses and initialization parameters.
- A physical standby database can now take advantage of the rolling upgrade feature provided by a logical standby. Through the use of the new KEEP IDENTITY clause option to the SQL ALTER DATABASE RECOVER TO LOGICAL STANDBY statement, a physical standby database can be temporarily converted into a logical standby database for the rolling upgrade, and then reverted back to the original configuration of a primary database and a physical standby database when the upgrade is done.
- In the same Data Guard configuration now it allows a mix of Linux and Windows primary and standby databases.
New Features in Oracle Data Guard 11.1 (Applicable to only Redo Apply)
- You can open ans query physical standby database while continuing to receive and apply redo data from a primary database.
- There comes snapshot standby database which is new type of updatable standby database.
- You can use the RMAN DUPLICATE command to create a physical standby database over the network without a need for pre-existing database backups.
- Lost-write detection feature using a physical standby.
New Features in Oracle Data Guard 11.1 (Applicable to SQL Apply only)
- DBMS_RLS, DBMS_FGA PL/SQL Packages are supported and also XML stored as CLOB.
- Transparent Data Encryption (TDE) is supported in SQL apply. This allows a logical standby database to provide data protection for applications with advanced security requirements.
- Data Guard SQL Apply parameters can be set dynamically.
- When switching over to a logical standby database where either the primary database or the standby database is using Oracle RAC, the SWITCHOVER command can be used without having to shut down any instance, either at the primary or at the logical standby database.
- Scheduler Jobs can be created on a standby database using the PL/SQL DBMS_SCHEDULER package and can be associated with an appropriate database role so that they run when intended (for example, when the database is the primary, standby, or both).
New Features in Oracle Data Guard 11.2 (Applicable to both Redo Apply and SQL Apply)
- Data Guard configuration now support up to 30 standby databases.
- In Oracle 10g there was introduced flash recovery area. Starting from Oracle 11g the place is known as fast recovery area. In 11gR2 the fast recovery area location changed from LOG_ARCHIVE_DEST_10 to LOG_ARCHIVE_DEST_1.
- The initialization parameter FAL_CLIENT is deprecated.
- Redo transport compression is no longer limited to compressing redo data only when a redo gap is being resolved. When compression is enabled, all redo data sent is compressed.
- The ALTER SYSTEM FLUSH REDO SQL statement can be used at failover time to flush unsent redo from a mounted primary database to a standby database, thereby allowing a zero data loss failover even if the primary database is not running in a zero data loss data protection mode.
New Features in Oracle Data Guard 11.2 (Applicable to both Redo Apply only)
- Apply lag tolerance can be configured by using the new STANDBY_MAX_DATA_DELAY parameter.
- The "ALTER SESSION SYNC WITH PRIMARY" SQL statement can be used to ensure that a physical standby database is synchronized with the primary database as of the time the statement is issued.
- The V$DATAGUARD_STATS view now has apply lag and transport lag columns. Data inside the view columns also contain more accurate information.
- The new V$STANDBY_EVENT_HISTOGRAM view has been introduced where we can see the histogram of apply lag values on the physical standby database.
- A corrupted data block in a primary database can be automatically replaced with an uncorrupted copy of that block from a physical standby database and vice versa.
New Features in Oracle Data Guard 11.2 (Applicable to only SQL Apply)
- Logical standby databases and the LogMiner utility support tables with basic table compression and OLTP table compression.
- Logical standby and the LogMiner utility support tables with SecureFile LOB columns. Compression and encryption operations on SecureFile LOB columns are also supported.
- Online redefinition performed at the primary database using the DBMS_REDEFINITION PL/SQL package is transparently replicated on a logical standby database.
- Logical Standby supports the use of editions at the primary database, including the use of edition-based redefinition to upgrade applications with minimal downtime.
- Logical standby databases support Streams Capture. This allows you to offload processing from the primary database in one-way information propagation configurations and make the logical standby the hub that propagates information to multiple databases. Streams Capture can also propagate changes that are local to the logical standby database.
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