International Business Machines Corporation

Lubor J Kollar

Jean G Fecteau

Eugene Kligerman

Sriram Kolinjivadi Padmanabhan

Timothy Ray Malkemus

Anant Deep Jhingran

Fred Koo

Chaitanya K Baru

Jo-Anne M Kirton

Gilles Fecteau

A method and apparatus for distributing data of a table across a parallel data base system having a plurality of interlinked database nodes. The table is partitioned in accordance with a predetermined partitioning arrangement and data of the table is distributed across a subset of the nodes in accordance with the partitioning arrangement. The partitioning arrangement can comprise horizontal or vertical partitioning. The partitioning arrangement can comprise a partitioning map defining the relationship of partitions of the table to said subset of nodes.

Method and apparatus for implementing partial declustering in a parallel

A method for localizing execution of subqueries and determining collocation of execution of subqueries in a shared-nothing database. The concept of compatible partitioning is used to localize database operations in order to eliminate excess processes and communication, and thereby improve response time and throughput for the database management system. The method reduces the number of process by reducing the number of nodes involved in processing a query and by combining multiple processes.

Method for localizing execution of subqueries and determining

Method and means are provided for simulating a contiguous data space within a computer memory, and for placing and accessing data objects of various sizes within the simulated contiguous data space. Multiple, sub-data spaces are concatenated in such a way that each page and each sub-data space in the contiguous data space are uniquely identified. Data objects are placed in the contiguous data space and at the first reference to a page of the data object, only the segment containing the referenced page in the contiguous data space is mapped to the database storage disk. Once a data space page is mapped, the operating system can read the page into memory without requesting a disk operation from the database manager. On modifying a page, if the database disk page location is changed, the contiguous data space page is remapped without changing the page address in the data space. Also, modified data pages are rewritten to the database storage disk in an ongoing manner set by the user, instead of at intervals set by the operating system.

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North York, Canada

Lubor J Kollar