When after-image file management is enabled, a record of each backup and each after-image file archived is written to the archival log. This information can be used to aid in the recovery of a damaged database provided there are complete sets of backup and AI extent archive records in the archival log file. For recovery, a complete set of archival records consists of the following:
A full backup record
One or more incremental backup records
One or more after-image file archive records
The information from all three records must be matched together as follows:
1. Start with a FULL backup.
2. Match INCREMENTAL backups to a FULL using the backup sequence number (field 6 from the 0032 records) and the backup sequence number (field number 6 in the 0033 records). If there are INCREMENTAL backups with the same backup sequence number as the FULL backup record, they must be sequenced by the incremental backup number (field 7 from the 0033 record).
3. Match the AI archives to the backups using the AI sequence number (field 9 from the 0032 record or field 10 from the 0033 record) to retrieve all after-image file archival records where the after-image file sequence number from the backup record is >= to field 7 of the after-image file archival records.
Once the correct records are identified, they can be used to drive the database recovery process using the backup volume names from the backup records and the target filename from the archival records.
A full backup record