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Database Administration
Protecting Your Data : After-imaging : Performing roll-forward recovery
 

Performing roll-forward recovery

To perform roll-forward recovery, roll forward all of the extents used since the last backup, in the order they were filled. You must roll forward all of the extents before you can start the database. If you inadvertently start a database before you restore all of the AI extents, the database engine rolls back any incomplete transactions. Although these transactions might be completed in other as yet unrestored AI files, they appear to the database engine as incomplete during the roll-forward process. If you start the database before you restore all of the extents, you must begin the roll forward again from the last backup.
Before performing roll-forward recovery, you must have the most recent database backup, all AI files generated since the most recent backup, and no missing files. The last file is usually the file in use when the system failed. If any AI file is missing, recovery can be performed up to the missing file, but no further.
Use the ROLL FORWARD qualifier of the RFUTIL utility to restore each file. The syntax is:
rfutil db-name -C roll forward -a ai-name
For complete syntax information see the RFUTIL ROLL FORWARD qualifier on page 1396.
The ROLL FORWARD qualifier fails if:
*You omit the After-image Filename (-a) parameter
*It cannot open the AI file
*You name the wrong AI file
If the system fails while you are running the ROLL FORWARD operation, restore the database files again and rerun the ROLL FORWARD operation.
The ROLL FORWARD qualifier always disables after-imaging for the database before beginning the roll-forward operation. After the roll-forward has completed, you must re-enable after-imaging with the AIMAGE BEGIN qualifier if you want continued AI protection.
To perform a partial roll-forward recovery, use the endtime or endtrans options. The endtime option lets you roll forward an AI file to a particular point. The endtrans option lets you roll forward an AI file to a particular transaction. For information on using these options, see RFUTIL ROLL FORWARD qualifier.
For more information about the ROLL FORWARD qualifier, see Recovering a Database and RFUTIL Utility.
* Roll forward with the OPLOCK qualifier
* Rolling forward multiple files