Multiple-Column Index Compression With Sort Order Recovery

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Solution Overview

Problem

Existing technologies face challenges in compressing multiple column index tables in databases, as order preserving compression schemes lose the sort order information of subsequent columns, leading to inefficiencies and resource consumption.

Innovation Solution

Implement order preserving compression (OPC) on multiple column index tables, preserving the initial column's order while determining modification factors for subsequent columns, and using these factors to recover the order during query processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If order preserving compression is applied to multiple column index tables, then storage space is reduced, but sort order information of subsequent columns is lost

Engineering Contradiction:

Improvestorage spaceVSAvoidsort order information

Core Design Contradiction:

Quantity of substanceVSLoss of information

Solution Approach 1:

The patent extracts sort order information from subsequent columns during compression and stores it separately in a modification factor column. This allows the main index table to be compressed while the extracted sort order information is preserved independently for later query operations.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary action by calculating and storing modification factors that capture sort order information before actual query operations occur. These modification factors are pre-computed and stored in the index table, enabling efficient recovery of sort order information when needed without reprocessing the entire index.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If modification factors are stored for each subsequent column, then query processing efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvequery processing efficiencyVSAvoidindex table structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The modification factor column serves multiple functions: it stores sort order information for subsequent columns, acts as a compression marker, and enables efficient query processing. This multi-functional design reduces the need for separate structures for each purpose.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the parameter representation by storing modification factors that encode sort order information in a compact form. Instead of storing complete sort order sequences, it uses modified parameter values that can be computed and stored more efficiently.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12455866B2Multiple column order preserving compression

Publication Date: 2025.10.28 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Methods, computer program products, and systems are presented. The method computer program products, and systems can include, for instance: performing order preserving compression of a multiple column index table of a database to provide an encoded index table sorted by an initial column, wherein the multiple column index table includes the initial column and one or more subsequent column; and determining, in dependence on a result of the performing the order preserving compression, at least one modification factor for respective ones of the one or more subsequent column.