Unisys OS 2200 databases: Difference between revisions

Revision as of 18:31, 2 August 2009

Revision as of 12:26, 5 March 2010

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The heart of the database and transaction system is Integrated Recovery. “Integrated” implies the integration of all data models, the transaction file manager, the transaction scheduler, and the message queues. All activity in all of these areas is [[Journal (computing)|journaled]] (written to the [[Audit trail|audit trail]]). The audit trail is managed by the Exec which ensures synchronization for all users.<ref>Unisys Corporation (2009). <u>Integrated Recovery Conceptual Overview</u>. (Unisys publication 7830 8186). Roseville, MN. http://public.support.unisys.com/2200/docs/cp12.0/pdf/78308186-003.pdf </ref>

The Integrated Recovery Utility (IRU) is the heart of the recovery system. It provides database backup synchronized with executing transactions and the audit trails. Transactions and batch applications do not need to be stopped to back up the database. IRU makes that unnecessary. All backups can be performed in a running system. Start-of-backup and complete-backup sentinel blocks are written to the audit trail. IRU uses these blocks and other information on the audit trail to perform the fastest possible recovery operations.