Remote duplicate database facility with database replication support for online line DDL operations

摘要

A local computer system has a local database, application programs that modify the local database, and a transaction manager that stores audit records in a local audit trail reflecting those application program modifications to the local database. A remotely located computer system has a backup database. A remote data duplication facility (RDF) maintains virtual synchronization of the backup database with the local database. The RDF includes an extractor process executed by the local computer system, and a receiver process and a plurality of updater processes executed by the remote computer system. The extractor process extracts audit records from the local audit trail and transmits those records to the receiver process. The receiver distributes the received audit records to a plurality of image trail files in the remote computer system for processing by updater processes, which initiate redo operations of database modifications denoted in at least a subset of the audit records against the backup database. A catalog manager on the local computer system performs online database restructurings while application programs continue to modify the database. The transaction manager stores a Stop Updaters audit record in the local audit trail when each online database restructuring successfully completes. The extractor process transmits the Stop Updaters audit record to the remote computer system and the receiver process moves a copy each received Stop Updaters audit record into all of the image trails. Finally, each updater process stops execution when it reads a Stop Updaters audit record in its assigned image trail file.