DB2 10.5 for Linux, UNIX, and Windows

Restoring to an existing database

For a database-level restore, the backup image can differ from the existing database in its alias name, its database name, or its database seed. A database seed is a unique identifier for a database that does not change during the life of the database.

The database manager assigns the seed when you create the database. DB2® always uses the seed from the backup image.You can restore a table space into an existing database only if the table space exists and if the table spaces are the same, meaning that you did not drop the table space and then re-create it between the backup and the restore operations. The database on disk and in the backup image must be the same.You cannot modify the currently defined storage groups or explicitly create new storage groups when restoring a table space.

Before you perform a RESTORE DATABASE on an existing image of the database, you must reset the connect_proc parameter to NULL. If the connect_proc is not set to NULL, you might encounter ERROR SQL0440N when you attempt a connection or rollforward command. To avoid this error, you must update the connect_proc parameter to NULL by using the db2 update db cfg for <DATABASE> using connect_proc NULL command.

When restoring to an existing database, the restore utility performs the following actions:

Deletes table, index, and long field data from the existing database and replaces it with data from the backup image.
Replaces table entries for each table space that you are restoring.
Retains the recovery history file unless it is damaged or has no entries. If the recovery history file is damaged or contains no entries, the database manager copies the file from the backup image. If you want to replace the recovery history file, you can issue the RESTORE DATABASE command with the REPLACE HISTORY FILE parameter.
Retains the authentication type for the existing database.
Retains the database directories for the existing database. The directories define where the database is located and how it is cataloged.
Compares the database seeds. If the seeds are different, the utility performs the following actions:
- Deletes the logs that are associated with the existing database.
- Copies the database configuration file from the backup image.
- Sets the NEWLOGPATH parameter for the RESTORE DATABASE command to the value of the logpath database configuration parameter if you specified the NEWLOGPATH parameter.
If the database seeds are the same, the utility performs the following actions:
- Deletes all log files if the image is for a non-recoverable database.
- Deletes empty log files if the image is for a recoverable database. Non-empty log files are not affected.
- Retains the current database configuration file.
- Sets the NEWLOGPATH parameter for the RESTORE DATABASE command to the value of the logpath database configuration parameter if you specified the NEWLOGPATH parameter. Otherwise, the utility copies the current log path to the database configuration file. Validates the log path. If the database cannot use the path, the utility changes the database configuration to use the default log path.