Optimized technique for prefetching LOB table space pages
AssigneeInternational Business Machines Corporation
InventorsCharles Roy Bonner, Robert William Lyle
Life of this patent
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Abstract
A method, apparatus, and article of manufacture for a computer implemented technique for prefetching pages. Pages are prefetched from a database stored on a data storage device connected to a computer. Pages to be retrieved are identified. Identifiers for the identified pages are stored in multiple prefetch page lists. Concurrently, the retrieved pages are processed and prefetch commands are issued to alternating multiple prefetch page lists.
Claims26
A method of prefetching data from a database stored on a data storage device connected to a computer, wherein the method comprises:
- identifying data to be retrieved;
- creating a plurality of prefetch page lists;
- accessing at least one space map comprising page identifiers that logically represent pages in the database associated with the identified data, the at least one space map being stored within the database, and retrieving page identifiers for the identified data and storing the retrieved page identifiers in the plurality of prefetch page lists;
- and
- executing the prefetch page lists by alternating between each prefetch page list that comprises the plurality of prefetch page lists, wherein identified pages retrieved by one of the prefetch page lists are processed while prefetch commands are concurrently issued by another one of the prefetch page lists.
An apparatus for prefetching data from a database, comprising:
- a computer having a data storage device connected thereto, wherein the data storage device stores the database;
- one or more computer programs, performed by the computer, for identifying data to be retrieved, creating a plurality of prefetch page lists, accessing at least one space map comprising page identifiers that logically represent pages in the database associated with the identified data, the at least one space map being stored within the database, and retrieving page identifiers for the identified data and storing the retrieved page identifiers in the plurality of prefetch page lists, and executing the prefetch page lists by alternating between each prefetch page list that comprises the plurality of prefetch page lists, wherein identified pages retrieved by one of the prefetch page lists are processed while prefetch commands are concurrently issued by another one of the prefetch page lists.
An article of manufacture comprising a computer program carrier readable by a computer and embodying one or more instructions executable by the computer to perform a method for prefetching data from a database stored in a data storage device connected to the computer, wherein the method comprises:
- identifying data to be retrieved;
- creating a plurality of prefetch page lists;
- accessing at least one space map comprising page identifiers that logically represent pages in the database associated with the identified data, the at least one space map being stored within the database, and retrieving page identifiers for the identified data and storing the retrieved page identifiers in the plurality of prefetch page lists;
- and
- executing the prefetch page lists by alternating between each prefetch page list that comprises the plurality of prefetch page lists, wherein identified pages retrieved by one of the prefetch page lists are processed while prefetch commands are concurrently issued by another one of the prefetch page lists.
Dependencies are inferred from the claim text.