International Business Machines Corporation

Ibm Canada Limited - Ibm Canada Limitee

Sarah Posner

Adam J Storm

Sam Sampson Lightstone

Christian Marcelo Garcia-Arellano

Roger Luo Quan Zheng

Wojciech Kuczynski

Matthew Albert Huras

Michael Jeffrey Winer

Roger L Q Zheng

Catherine Suzanne McArthur

Jeffrey James Goss

Miroslaw Adam Flasza

Lorysa M Meadowcroft

Miroslaw A Flasza

Jeffrey J Goss

Catherine S Mcarthur

Michael J Winer

Matthew A Huras

Roger L Zheng

There are disclosed systems and computer program products for dynamically resizing memory pools used by database management systems. In one aspect, if a decrease in allocation to the memory pool is required, at least one page grouping that may be freed from the memory pool is identified as a candidate based on its position in a list of page groupings. If the page grouping contains any used memory blocks, the used memory blocks may be copied from a candidate page grouping to another page grouping in the list in order to free the candidate page grouping. Once the candidate page grouping is free of used memory blocks, the candidate page grouping may be freed from the memory pool. As an example, this system or computer program product may be used for dynamically resizing locklists or lock memory.

Systems for dynamically resizing memory pools

There are disclosed methods for dynamically resizing memory pools used by database management systems. In one aspect, if a decrease in allocation to the memory pool is required, at least one page grouping that may be freed from the memory pool is identified as a candidate based on its position in a list of page groupings. If the page grouping contains any used memory blocks, the used memory blocks may be copied from a candidate page grouping to another page grouping in the list in order to free the candidate page grouping. Once the candidate page grouping is free of used memory blocks, the candidate page grouping may be freed from the memory pool. As an example, this method may be used for dynamically resizing locklists or lock memory.

Methods for dynamically resizing memory pools

A system and method handle resource transaction requests. The system marks a waiting transaction request, having an access mode which is incompatible with the access mode of the executing transaction, with an ignore bit, so that a transaction request with an access mode compatible with the access mode of the executing transaction may receive a lock in order to access the resource. The transaction request is then marked with a bypass indicator such that when the executing transactions are finished accessing the resource, the waiting transaction request may be notified that it may have access to the resource. The system includes the ignore bit so that each transaction request that arrives after the ignore bit has been set, does not suffer from a long waiting time before being provided access to the resource.

System and method for handling resource transaction requests

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Toronto, Canada

Sarah Posner