Unisys Corporation

Ellen L Sorenson

Jane Muccio

Roger V Ritchie

David M Ciminski

Monica M Langsford

Database performance may be improved by creating additional backups from an existing backup, rather than the original database or audit log source. A second backup may be created from a first backup by copying the files from the first backup to the second backup. The replication from a first backup to a second backup with modification of the file history information allows identical backups to exist on different types of storage devices, including virtual storage devices. Continue functionality may be implemented during a move function to restart replication at a new starting point while retaining the existing move set. Tape-type-override functionality may be implemented during the replication to replace the tape type for the backups with another compatible type while retaining the original type for history file entries, tape trailers, and messages.

Database replication with continue and tape-type-override functions

A method includes receiving, at a processor, a timestamp as a start-point for extracting information from the storage tape. The method further includes determining, by the processor, a reel identification and a device type of a storage tape. The method further includes extracting the information, by the processor, from the storage tape starting at the start-point. The method further includes determining, by the processor, whether an end-point of the information has been reached. The method further includes reproducing, by the processor, the information to a computer-readable medium. The method further includes formatting, by the processor, the information to conform with format requirements of an activity log analyzing tool.

Extraction of audit trails

A rollback record may be created for each step identifier (ID). The rollback record indicates how many times the step record identified by the step ID has been rolled back during operation of the database. The rollback record may be stored in a periodic save record (PSR), separate from or stored in an audit trail containing the step records. By processing the rollback records in the periodic save record during a recovery, a database may identify a time on an audit trail for initiating a recovery prior to the last resume point for a step without going back in the audit trail to a time before the initial start of the step.

Rollback counters for step records of a database

One or more transactions, and their audited update actions, operating on a database may be identified by a step ID. The step ID may include a first set of bits identifying a time the step was created. The step ID may also include a second set of bits uniquely identifying a step created at a certain time from other step created at the same time. The first set of bits may be generated from a coordinated universal time (UTC) that does not change with local seasons, such as daylight saving time.

Step identifier based on a universal timestamp

A backup system override may be specified to allow a backup system to access a backup created on an old storage device. For example, an archival backup may be accessed long after the storage device that created the backup has been decommissioned. The file history information in the backup may specify a storage device no longer accessible by the backup system. An override in the backup system allows the backup system to access the backup with the file history information through a different storage device than the storage device that created the backup. The different storage device may have a different name and/or be of a different type than the original storage device that created the backup. The override may also allow access to command scripts and links in the backup.

Device type override

Audit Trail recovery is enhanced by including addresses of immediately prior periodic saves of all active or open Steps or transactions in each new period save area. Reduced cost in main memory usage and on-the-fly processing to accomplish audit trail format that enhances recovery time results from ability to immediately address next prior period save data once a last periodic save is found in reading back the audit trail. Reading back the audit trail to find the last periodic save can be avoided too by directly addressing the last periodic save in preferred embodiments since the computer system will in all events temporarily maintain a record of the address of the last periodic save to record the next time a periodic save is to be made, so this temporarily maintained record can be accessed and used to jump directly to the last periodic save address on the audit trail. Accordingly all periodic saves prior to the current one are readily discovered and the earliest open transaction or Step is thus located quickly, allowing the audit trail based recovery to initiate quickly.

Using periodic spaces of block ID to improve additional recovery

A database backup process and system are disclosed in various embodiments. A backup copy of the database is created and a timestamp indicating the time at which the backup copy was created is written to a first history file. A plurality of backup copies of a database audit file are concurrently created, and device identifiers referencing respective devices on which the backup copies of the audit file were created and timestamps indicating respective ranges of audit records in the backup copies of the audit file are written to a plurality of move-history files respectively associated with the plurality of backup copies of the audit file.

Growing community of inventors

Mounds View, MN, United States of America

Ellen L Sorenson