Non-blocking drain method and apparatus used to reorganize data in a database

摘要

A method and apparatus for online reorganization of a database which does not prevent a process from accessing the database during the data reorganization. The invention uses a non-blocking drain to lock on a database, unloads a copy of the data contained in the database, reorganizes the copied data, loads the reorganized data into a shadow location, applies log records to the shadow location data so that the reorganized data may be adjusted for any changes to the database after the data was copied and reorganized, and then replaces the data in the database with the reorganized data. The non-blocking drain does not prevent other requests on the database from being processed while the reorganization lock is in place, except briefly when the reorganized data replaces the data in the database.