International Business Machines Corporation

Thomas Paul Giordano

David Rolland Welsh

Robert J Bestgen

Thomas Owen McKinley

Barry Warren Knapp

Randy Lynn Egan

Mark John Anderson

David Glenn Carlson

Yun Bj Wang

Kristopher Craig Whitney

Scott Dennis Helt

Kevin Curtis Griffin

David Andrew Jones

William Anton Brown

Jennifer Anne Dervin

Carol Ledermann Ramler

Scott Joseph Heimer

Robert Paul Mech

Curtis D Schemmel

Mukesh Rathor

Shauna Rollings

Techniques for warm cloning of computing nodes are provided. A request to clone a first computing node is received. Upon determining that a first transaction of a plurality of transactions is ongoing, a first moment in time when data associated with the first transaction was coherent on the first computing node is identified. Tracking data related to the first transaction is collected, beginning at the first moment in time. Further, a first storage associated with the first computing node is copied to a second storage associated with a second computing node, where the first transaction continues during the copying. The tracking data related to the first transaction is then transmitted to the second computing node.

Coherent cloning of active compute nodes

Techniques for recycling segment pages while preserving integrity of memory addressing. Upon a request to delete a system object, an initial segment identifier is de-assigned from a segment of the system object, and each segment page of the system object is remapped to a new virtual address range. The segment is stored as a reusable segment in a reusable segment store. Upon a request to access the system object, an exception is raised that the system object does not exist. Upon a request to create a new system object, the reusable segment store is searched to identify the reusable segment as a match. The reusable segment is assigned as a segment of the new system object.

Recycling segment pages while preserving integrity of memory addressing

A method and computer program product are provided for implementing skip key processing for database grouping queries involving aggregate operations using one or more indices in a computer system. First checking for a selected entry in a current group in a primary file is performed. Responsive to finding the selected entry in the current group, the set of records of the current group is ordered to provide an aggregate value in an aggregate field of the current group. Then checking for an excluded value in the aggregate field of the current group is performed. Responsive to not finding the excluded value in the aggregate field, a current entry is saved as a result for the group. Then checking for more groups in the primary file is performed. Responsive to finding more groups in the primary file, a unique key or prefix to the query index is obtained to position to a next group. When the selected entry in the next group is not found, then checking for more groups in the primary file is performed.

Method and computer program product for implementing skip key processing for database grouping queries involving aggregate operations by using one or more indices

A method and computer program product are provided for processing and combining data sets including bitmaps in a computer system. A plurality of initial data subsets to be combined are processed and data structure statistics containing predefined data attributes are built for each of the plurality of initial subsets. Checking for a dynamic selection attribute for each of the plurality of initial subsets is performed. Responsive to the dynamic selection attribute not being identified, the intermediate storage requirements for producing the combined final data set is selectively optimized. Responsive to identifying the dynamic selection attribute, both intermediate result regeneration and intermediate storage requirements for producing a combined final data set are selectively optimized.

Method and computer program product for processing and combining data sets including bitmaps

A method and computer program product are provided for paging control using a reference structure in a computer system. The reference structure is scanned to identify a next selected entry for an IO range building routine. The next selected entry is compared with a set hardlimit value. Responsive to the next selected entry being greater than the hardlimit value, the IO range building routine is exited. A shortlimit value is identified. The next selected entry is compared with the identified shortlimit value. Responsive to the next selected entry being greater than the identified shortlimit value, the IO range building routine is exited. A first array is used for storing entry IDs for selected entries found from scanning the reference structure and a second array is used for tracking blocks of storage used for the selected entries.

Method and computer program product for paging control using a reference

In parallel process computer systems multiple tasks are simultaneously executed. However, where resource contention exists, the multiple tasks become serialized, reducing system performance. Once such resource contention is arm contention during reads for files stored under multiple arms on direct access storage devices (DASDs). According to the preferred embodiment, a method is provided that assigns read tasks in a manner that reduces the probability of arm contention during the file reads. First, the plurality of extents storing the file are correlated to their associated arm. Second, for each of the plurality of arms, the attributes of extents under that arm, preferably including the extent read times, are accumulated. Finally, the plurality of simultaneous read tasks are assigned to the plurality of extents according to the accumulated attributes such that arms that have a greater need for service are favored over arms that have a lesser need when reading the file. Assigning the tasks in this manner lessons the probability of arm contention during file reads, increasing system performance.

Computer mechanism for reducing DASD arm contention during parallel

The present invention involves a database administrator that is comprised of a plurality of database managers and a plurality of database servers. The database managers act as an interface between the database servers and client programs and the database servers act as an interface between the database managers and the database itself. The client programs, database managers, and database servers all execute within a single-level-store environment, which allows them to communicate with one another without incurring the expense of inter-address space communication and/or the expense associated with the cross-address space mapping of query results.

Parallel database serving mechanism for a single-level-store computer

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Rochester, MN, United States of America

Thomas Paul Giordano