Category: dataguard

DataGuard Common Errors

ORA-16664: unable to receive the result from a database Failed. So this will cause issues now throughout the world.
Unable to switchover, primary database is still "wzsdb"

Continue reading

Advertisements

Snapshot Standby

 

One interesting feature of Oracle Dataguard introduced with 11g :

Snapshot Standby database where we can basically convert the physical standby database into a read-write real time clone of the production database and we can then temporarily use this environment for carrying out any kind of development testing, QA type work or to test the impact of a proposed production change on an application.

The command that performs this activity is :

SQL>  ALTER DATABASE CONVERT TO SNAPSHOT STANDBY;

The database role gets changed :


SQL> select open_mode,database_role from v$database; OPEN_MODE DATABASE_ROLE ---------- ---------------- READ WRITE SNAPSHOT STANDBY

To move it back to physical standby :

SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY;

 

ref : http://gavinsoorma.com/2009/09/11g-snapshot-standby-for-real-time-testing/

Recovering Through the OPEN RESETLOGS Statement

Data Guard allows recovery on a physical standby database to continue after the primary database has been opened with the RESETLOGS option. When an ALTER DATABASE OPEN RESETLOGS statement is issued on the primary database, the incarnation of the database changes, creating a new branch of redo data.When a physical standby database receives a new branch of redo data, Redo Apply automatically takes the new branch of redo data. For physical standby databases, no manual intervention is required if the standby database did not apply redo data past the new resetlogs SCN (past the start of the new branch of redo data). The following table describes how to resynchronize the standby database with the primary database branch.

image

See Oracle Database Backup and Recovery Advanced User’s Guide for more information about database incarnations, recovering through an OPEN RESETLOGS operation, and
Flashback Database.

ref : http://docs.oracle.com/cd/B19306_01/server.102/b14239/toc.htm