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:
Aug. 27, 1991
Filed:
Jul. 15, 1988
Applicant:
Inventors:
Josephine M Cheng, San Jose, CA (US);
Akira Shibamiya, Los Altos, CA (US);
Yun Wang, Sunnyvale, CA (US);
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ; G06F / ; G06F / ; G06F / ;
U.S. Cl.
CPC ...
364200 ; 36493146 ; 3649621 ; 3649622 ; 3649624 ; 364963 ; 3649634 ; 3649744 ; 3649746 ; 3642253 ; 3642823 ; 3642824 ; 3642831 ; 3642834 ;
Abstract
This invention measures the degree of clustering of an index for a relational data base table, estimates the number of physical page accesses required to access the table using a partial index scan using the index, and selects the index providing the fastest access path to the table. The degree of clustering is measured as follows: