Hash composite indexes

US11341120B2 · kind B2 · utility

Assignee

• SAP SE · DE

Inventors

• Robert Schulze · Walldorf, DE
• Holger Bischoff · Dielheim, DE
• Neeraj Kulkarni · Santa Clara, US

Key dates

• Filing date: May 13, 2020
• Grant date: May 24, 2022
• Expiry date: May 27, 2040

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F2212/1044
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

Disclosed herein are system, method, and computer program product embodiments for creating a dictionary-free index. An embodiment operates by a database maintaining database table comprises a column and a row. The database creates a concatenated string index comprising a concatenated string value based on the database column's row. The database also creates a hash value list having a hash value based on the concatenation string index's concatenated string value. Thereafter, the database creates a directory having a pointer to (i) a row position of the hash value list or (ii) a row position of a collision list having the row position of the hash value in the hash value list. The database also creates a collision list containing the row positions of the hash values occurring multiple times in the hash value list. The index for the database table includes the hash value list, the directory, and the collision list.