Ncr Corporation

Rolf G E Stegelmann

Chi Kim Hoang

James J Chen

Mark Anthony Hodgens

Fred S Kaufmann

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.

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Valencia, CA, United States of America

Rolf G E Stegelmann