First I will describe about some common problem regarding Dataguard which are as follows:
Common Problems:
If you encounter a problem when using a standby database, it is probably because of one of the following reasons:
- Standby Archive Destination Is Not Defined Properly
- Renaming Datafiles with the ALTER DATABASE Statement
- Standby Database Does Not Receive Redo Data from the Primary Database
- You Cannot Mount the Physical Standby Database
Standby Archive Destination Is Not Defined Properly
If the STANDBY_ARCHIVE_DEST initialization factor does not stipulate a applicable list of directions label on the standby database, the Oracle database will not be competent to ascertain the list of directions in which to warehouse the archived redo log files. Check the DESTINATION and ERROR posts in the V$ARCHIVE_DEST scenery by moving into the subsequent query and assure the location stayed at is valid:
SQL> SELECT DESTINATION, ERROR FROM V$ARCHIVE_DEST;
Renaming Datafiles with the ALTER DATABASE Statement
You cannot rename the datafile on the standby site when the STANDBY_FILE_MANAGEMENT initialization parameter is set to AUTO. When you set the STANDBY_FILE_MANAGEMENT initialization parameter to AUTO, use of the following SQL statements is not allowed:
ALTER DATABASE RENAMEALTER DATABASE ADD/DROP LOGFILEALTER DATABASE ADD/DROP STANDBY LOGFILE MEMBERALTER DATABASE CREATE DATAFILE AS
If you attempt to use any of these statements on the standby database, an error is returned. For example:
SQL> ALTER DATABASE RENAME FILE '/disk1/oracle/oradata/payroll/t_db2.log' to 'dummy';
alter database rename file '/disk1/oracle/oradata/payroll/t_db2.log' to 'dummy' * ERROR at line 1: ORA-01511: error in renaming log/data files ORA-01270: RENAME operation is not allowed if STANDBY_FILE_MANAGEMENT is auto
Standby Database Does Not Receive Redo Data from the Primary Database
If the standby place is not accepting redo written knowledge, query the V$ARCHIVE_DEST scenery and review for wrongdoing messages. For instance, move into the subsequent query:
SQL> SELECT DEST_ID "ID",
2> STATUS "DB_status",
3> DESTINATION "Archive_dest",
4> ERROR "Error"
5> FROM V$ARCHIVE_DEST WHERE DEST_ID <=5;
ID DB_status Archive_dest Error
-- --------- ------------------------------ ------------------------------------
1 VALID /vobs/oracle/work/arc_dest/arc
2 ERROR standby1 ORA-16012: Archivelog standby database identifier mismatch
3 INACTIVE
4 INACTIVE
5 INACTIVE
5 rows selected.
If the end wares of the query does not aid you, review the subsequent table of probable issues. If any of the subsequent circumstances survive, log transport services will bungle to spread redo written knowledge to the standby database:
- The service label for the standby case is not configured in the right way in the
tnsnames.ora record for the main database.
- The Oracle Net service label individual by the
LOG_ARCHIVE_DEST_n factor for the main database is incorrect.
- The
LOG_ARCHIVE_DEST_STATE_n factor for the standby database is not set to the worth ENABLE.
- The
listener.ora record has not been configured in the right way for the standby database.
- The listener is not commenced at the standby site.
- The standby case is not started.
- You have adjoined a standby archiving location stayed at to the main SPFILE or text initialization factor record, but have not yet empowered the change.
- You employed an invalid backup as the foundation for the standby database (for instance, you employed a backup from the erroneous database, or did not bring ahead the standby manipulate record employing the correct method).
You Cannot Mount the Physical Standby Database
You not able to get on the standby database if the standby manipulate record was not brought ahead with the ALTER DATABASE CREATE [LOGICAL] STANDBY CONTROLFILE ... assertion or RMAN command. You not able to use the subsequent sorts of manipulate record backups:
- An running system-created backup
- A backup brought ahead employing an
ALTER DATABASE assertion without the [PHYSICAL] STANDBY or LOGICAL STANDBY option
To check actual tale size of oracle is really can be hectic for you if you dont know much about oracle blocks, extents, segment and specially PCT free and PCT used concepts, and there is no actual function in oracle to check the table size,
