International Business Machines Corporation

Gary Howard Sockut

Thomas Abel Beavin

Craig Alan Friske

Stephen Walter Turnbaugh

Balakrishna Raghavendra Iyer

James Z Teng

James Alan Ruddy

James Zu-Chia Teng

Julie Ann Watts

Kalpana Shyam

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.

Non-blocking drain method and apparatus for use in processing requests on a resource

An in-place reorganization of a database achieves reasonably accurate results for users during high-throughput concurrent usage of the database. The reorganization's movement of records across a user transaction's position within a scan of the database is tracked. The behavior of the user transaction is corrected to account for the movement of the records.

Methods for in-place online reorganization of a database

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

The present invention includes reorganization of a Database Management System (DBMS). The reorganization of the present invention is implemented by recording a first current Relative Byte Address (RBA). Then, data is copied from the old area in the table space to a new area in the table space in reorganized form. In the present invention, throughout most of reorganization a user maintains access to the DBMS's normal facilities to read and write to the old area. The DBMS uses its normal facilities to record writing, which occurs during reorganization, in a log. The reorganization in accordance with the present invention reads the log (that has been written to during reorganization) and processes the log to the new area to bring the new area up to date. This process is performed with the use of a RID mapping table. Finally, at the end of reorganization, the user's access is switched from the old area to the new area.

Interaction between application of a log and maintenance of a table that

A primary database's log records are used to update a second database that has a different encoding scheme than the log record and the primary database. This encoding scheme, for example, may involve compression, encryption, or another data transformation. First, a stale encoded data record from the second database is identified. This data record is one whose counterpart in the primary database has been updated in the primary database and where update has been logged. The stale data record is modified to reflect its contents as encoded by the first encoding scheme rather than the second. Then, the logged change is applied to update the modified record. The updated record is then decoded and subsequently re-encoded according to the second encoding scheme. This record is then stored in the second database replacing the stale second data record.

Application of log records to data compressed with different encoding

The present invention includes reorganization of a Database Management System (DBMS) The reorganization of the present invention is implemented by recording a first current Relative Byte Address (RBA) Then, data is copied from the old area in the table space to a new area in the table space in reorganized form. In the present invention, throughout most of reorganization a user maintains access to the DBMS's normal facilities to read and write to the old area. The DBMS uses its normal facilities to record writing, which occurs during reorganization, in,a log. The reorganization in accordance with the present invention reads the log (that has been written to during reorganization) and processes the log to the new area to bring the new area up to date. This process is performed with the use of a RID mapping table. Finally, at the end of reorganization, the user's access is switched from the old area to the new area.

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San Jose, CA, United States of America

Gary Howard Sockut