Ncr Corporation

Teradata Us, Inc.

Mark Anthony Hodgens

Chi Kim Hoang

James J Chen

Fred S Kaufmann

Donald Raymond Pederson

Frederick Stuart Kaufmann

Gary Allen Roberts

Rolf G&uuml;nter Erich Stegelmann

Rolf G E Stegelmann

A method, apparatus, and article of manufacture for accessing data in a computer system. Compression and decompression functions are associated with a column of the table, in order to perform compression of decimal, numeric or date data stored in the column when the data is inserted or updated in the table, and in order to perform decompression of the data stored in the column when the data is retrieved from the table. The compression function compresses and stores the data in a fixed-length compressed field in the column without a length value, and the fixed-length compressed field has a size that is determined by a range of values for the data stored in the fixed-length compressed field. The decompression function retrieves and decompresses the data from the fixed-length compressed field.

Numeric, decimal and date field compression

A method, apparatus, and article of manufacture for accessing a subject table in a computer system. The subject table is partitioned across a plurality of processing units of the computer system. A user query or other request to access the subject table is split into a plurality of step messages, wherein each of the step messages is assigned to one of the processing units managing one or more of the partitions of the subject table. A plurality of actions are identified for each of the step messages, and one or more necessary records for these actions are retrieved from the partition of the subject table and stored into a corresponding partition of a spool table. The necessary records are selected in such a manner that none of the actions involved in the request need to access the partition of the subject table. The actions from the step message are then performed against the partitions of the spool table rather than the partitions of the subject table. An optimizer function uses information from the spool table to generate more efficient execution plans for the step message and its associated actions.

Very large table reduction in parallel processing database systems

A method, apparatus, and article of manufacture for accessing a subject table in a computer system. The subject table is partitioned across a plurality of processing units of the computer system. A trigger is defined for the subject table, such that when a triggering event occurs on the subject table, a triggered action is performed. Both the triggering event and triggered action can be performed in parallel by the computer system. A spool table is generated for each partition of the subject table, wherein the spool table stores one or more necessary records accessed from the subject table by the triggering event. In this manner, triggered actions that refer to these necessary rows need not access the subject table again.

Parallel optimized triggers in parallel processing database systems

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San Diego, CA, United States of America

Mark Anthony Hodgens