Classification of data in main memory database systems
First Claim
1. A method of managing storage of records in a main memory database system, comprising:
- logging, in a record access log, a sequence of record access observations of accesses of the records in the main memory database system;
identifying a subset of the records in the main memory database system to migrate from memory to secondary storage based on the sequence of the record access observations logged in the record access log over a time period from a beginning time to an end time, the subset of the records to migrate being identified based on classification of the records in the main memory database system, the classification of the records being based on access frequency estimate data updated as the record access log is scanned in reverse from the end time towards the beginning time, the subset of the records to migrate being identified prior to a record access observation for the beginning time being read during scanning of the record access log in reverse from the end time towards the beginning time; and
migrating the subset of the records in the main memory database system from the memory to the secondary storage.
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Accused Products
Abstract
Various technologies described herein pertain to classifying data in a main memory database system. A record access log can include a sequence of record access observations logged over a time period from a beginning time to an end time. Each of the record access observations can include a respective record ID and read timestamp. The record access log can be scanned in reverse from the end time towards the beginning time. Further, access frequency estimate data for records corresponding to record IDs read from the record access log can be calculated. The access frequency estimate data can include respective upper bounds and respective lower bounds of access frequency estimates for each of the records. Moreover, the records can be classified based on the respective upper bounds and the respective lower bounds of the access frequency estimates, such that K records can be classified as being frequently accessed records.
31 Citations
20 Claims
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1. A method of managing storage of records in a main memory database system, comprising:
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logging, in a record access log, a sequence of record access observations of accesses of the records in the main memory database system; identifying a subset of the records in the main memory database system to migrate from memory to secondary storage based on the sequence of the record access observations logged in the record access log over a time period from a beginning time to an end time, the subset of the records to migrate being identified based on classification of the records in the main memory database system, the classification of the records being based on access frequency estimate data updated as the record access log is scanned in reverse from the end time towards the beginning time, the subset of the records to migrate being identified prior to a record access observation for the beginning time being read during scanning of the record access log in reverse from the end time towards the beginning time; and migrating the subset of the records in the main memory database system from the memory to the secondary storage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computing system, comprising:
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a data repository that comprises a record access log, wherein the record access log comprises a sequence of record access observations of accesses of records in a main memory database system logged over a time period from a beginning time to an end time; at least one processor; and memory that comprises computer-executable instructions that, when executed by the at least one processor, cause the at least one processor to perform acts including; scanning the record access log in reverse from the end time towards the beginning time; for each time slice scanned as the record access log is scanned in reverse, at least one of; calculating access frequency estimate data for one or more of the records;
orrefining a calculation of the access frequency estimate data for the one or more of the records; classifying the records based on the access frequency estimate data as the record access log is scanned in reverse; identifying a subset of the records in the main memory database system to migrate from memory to secondary storage based on the classifying of the records, wherein the scanning of the record access log is discontinued prior to reading a record access observation for the beginning time. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A computing system, comprising:
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a data repository that comprises a record access log, wherein the record access log comprises a sequence of record access observations of accesses of records in a main memory database system logged over a time period from a beginning time to an end time; at least one processor; and memory that comprises computer-executable instructions that, when executed by the at least one processor, cause the at least one processor to perform acts including; scanning the record access log in reverse from the end time towards the beginning time; for each time slice scanned as the record access log is scanned in reverse, at least one of; calculating access frequency estimate data for one or more of the records;
orrefining a calculation of the access frequency estimate data for the one or more of the records; wherein the access frequency estimate data is stored in a table; classifying the records based on the access frequency estimate data as the record access log is scanned in reverse; removing a portion of the access frequency estimate data from the table as the record access log is scanned in reverse; identifying a subset of the records in the main memory database system to migrate from memory to secondary storage based on the classifying of the records. - View Dependent Claims (20)
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Specification