Patent ID: 6549895
Filing Date: 2003-04-15
Classification: G06F,Y10S

Abstract:
A method for data retrieval using index scanning in a database management system, the database management system including a processing unit operably coupled to physical storage for storing data, the physical storage containing at least one database table stored in a plurality of pages, each database table having a plurality of rows, and one or more indexes composed of a sequence of entries referencing the rows, and the processing unit having a buffer pool for caching data pages from the database table, said method comprising the steps of:(a) ranking selected entries of an index; (b) determining a distance parameter for each of said ranked index entries, wherein said distance parameter is derived from the relationship between said index and an index of lesser rank; (c) determining the number of consecutive index entries that can be stored in the buffer pool; and (d) estimating the number of page transfers based on the distance parameters and the number of consecutive index entries.