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Buffer Pool Scan Enhancement Technique

IP.com Disclosure Number: IPCOM000038728D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chalemin, GE: AUTHOR

Abstract

A method is described to provide increased performance of a scan used in Buffer Pool Management. In accordance with the new method, the Buffer Pool has a directory of halfwords which are scanned looking for a Field set to "0000"x. The Beginning Index Field is located in the Pool Header so that the previous scan can leave information for the next scan. A scan is done every time a process requests a buffer. The first scan has already checked the directory bytes up to the point where it found a Field set to "0000"x. It puts this index value in the Beginning Index Field so that the following scan doesn't have to bother checking directory bytes which were just checked.

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Buffer Pool Scan Enhancement Technique

A method is described to provide increased performance of a scan used in Buffer Pool Management. In accordance with the new method, the Buffer Pool has a directory of halfwords which are scanned looking for a Field set to "0000"x. The Beginning Index Field is located in the Pool Header so that the previous scan can leave information for the next scan. A scan is done every time a process requests a buffer. The first scan has already checked the directory bytes up to the point where it found a Field set to "0000"x. It puts this index value in the Beginning Index Field so that the following scan doesn't have to bother checking directory bytes which were just checked. Keeping the index in the Pool Header rather than in a static variable allows the Buffer Manager to manage multiple pools and allows the same pool to be used by a Buffer Manager in the Virtual Resource Manager as well as a Buffer Manager in the virtual machine. This is because all the information is contained in the pool rather than in the Manager program routine.

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