Hewlett-Packard Development Company, L.p.

Tandem Computers Incorporated

Roberta S Marton

David W Birdsall

Pedro Celis

James H Troisi

Donald S Maier

John M Hausman

Carol Jean Pearson

Kenneth K Luu

Emile Roth

A method for modifying an original data object in a database using a single command is disclosed. The single command is first validated. Once the command has been validated a ghost data object is created using the new definition. The ghost data object is populated with data from the original object. The transaction log records from the original data object are applied to the ghost data object. The original data object is then locked for exclusive access. The final transaction log records from the original data object are applied to the ghost data object. In the final step the database switches to the new data object. Dependent objects are automatically transformed as part of the same operation.

Single-operation on-line schema evolution

A database computer system includes memory, residing in a plurality of interconnected computer nodes, for storing database tables. Each database table has a plurality of columns, a primary key index based on a specified subset of the columns, and an associated table schema. At least a subset of the database tables are partitioned into a plurality of partitions, each partition storing records having primary key values in a primary key range distinct from the other partitions. A transaction manager generates and stores an audit trail, each audit entry denoting a database table record event, such as an addition, deletion or alteration of a specified database table record in a specified one of said database tables. Four online data definition procedures allow the structure of a database table to be altered while the database table remains available to execution of transactions, with minimal impact of the availability of the database table for transaction execution. The four online data definition procedures are a move partition procedure, a split partition procedure, a move partition boundary procedure, and a create new index procedure. Each of these online procedures has three or four phases of execution. In a first phase, records of a table partition or the entire table are accessed using read only access, so as to generate a new partition, move records between two partitions, or to create a new index. In a second phase, audit trail entries are used to clean up the data structures created during the first phase. In a third phase, access to the database table is briefly locked while audit trail entries created after the second phase are used to make final changes to the data structures created during the first phase, and while the database table schema is updated to reflect the changes to the database table produced.

Relational database system and method with high data availability during

Growing community of inventors

Fremont, CA, United States of America

Roberta S Marton