Browse Prior Art Database

Data Move Savings

IP.com Disclosure Number: IPCOM000048902D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chang, PY: AUTHOR

Abstract

A bit block algorithm has been developed to efficiently sort a file into memory and it is not possible to write back into the file. According to this algorithm, the total number of records in the file is divided by the total number of bits available for mapping. A bit is set on as the records are searched sequentially and any record represented by the bit is determined to qualify. Qualifying records are sorted into a limited work space called a bucket. Using this algorithm, records are moved from the file manager buffer to the sort bucket if one qualified record is found. A qualified record is defined as one which qualifies both the qualify conditions and is not in sort. Inserting one record at a time causes a lot of data movement in the sort bucket.

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Data Move Savings

A bit block algorithm has been developed to efficiently sort a file into memory and it is not possible to write back into the file. According to this algorithm, the total number of records in the file is divided by the total number of bits available for mapping. A bit is set on as the records are searched sequentially and any record represented by the bit is determined to qualify. Qualifying records are sorted into a limited work space called a bucket. Using this algorithm, records are moved from the file manager buffer to the sort bucket if one qualified record is found. A qualified record is defined as one which qualifies both the qualify conditions and is not in sort. Inserting one record at a time causes a lot of data movement in the sort bucket.

To minimize data movements, the file manager defines a new mode called "End of Buffer Pause". The sort only moves data when the file manager is at the end of its buffer and has to destroy the data in the file manager buffer. By minimizing data movements, faster sort performance is attained.

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