The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 07, 1998
Filed:
Jun. 07, 1995
Bernhard Schiefer, Scarborough, CA;
Arun Narasimha Swami, Cupertino, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method of index scanning involves scanning one or more selected indexes and determining the number of data transfers required to traverse all or a portion of a selected index for a selected number of buffer pool sizes. The number of page transfers to scan a whole table of interest versus the number of page transfers to scan each relevant index in accordance with the buffer pool size is determined for a query. The number of page transfers required in proportion to the selectivity of starting and stopping conditions is determined and scaled down in proportion to the selectivity of any starting and stopping conditions present in the search criteria in the query. A suitable correction factor is applied to the number of transfers to account for few rows remaining to be transferred after applying the search criteria, the buffer pool being large, or a low degree of clustering for an index,, as well as accounting for any remaining index sargable search criteria. The search procedures that results in the least number of page transfers in then implemented.