Database Table Statistics Fixation for Stable Query Plans

Solution Overview

Problem

Existing database management systems (DBMS) face challenges in selecting which tables to fix statistical information for, leading to unnecessary work costs and potential performance degradation due to inappropriate execution plans when data updates are not timely reflected in the statistical information.

Innovation Solution

An information processing apparatus that selects tables for statistical information fixation based on update frequency and record count thresholds, determining tables with high update frequency and record counts as targets to prevent performance degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If statistical information is fixed for all tables, then performance degradation is prevented, but unnecessary monitoring and maintenance work increases

Engineering Contradiction:

Improveperformance stabilityVSAvoidmonitoring efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating the fixation strategy based on table characteristics. Instead of uniformly fixing statistical information for all tables, the system identifies and fixes only those tables that meet specific criteria (high update frequency and/or high record count), thereby applying the fixation treatment locally where it is most needed while avoiding unnecessary work on other tables.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by using update frequency and record count as selection criteria to determine which tables should have their statistical information fixed. By changing the state of statistical information from dynamic to fixed based on these parameter thresholds, the system optimizes the balance between performance stability and monitoring efficiency.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If statistical information is not fixed, then monitoring and maintenance work is reduced, but performance degradation occurs due to outdated execution plans

Engineering Contradiction:

Improvemonitoring efficiencyVSAvoidperformance stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the fixation strategy based on table characteristics. Instead of uniformly fixing statistical information for all tables, the system identifies and fixes only those tables that meet specific criteria (high update frequency and/or high record count), thereby applying the fixation treatment locally where it is most needed while avoiding unnecessary work on other tables.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by proactively identifying tables that are likely to cause performance degradation before it occurs. By using update frequency and record count as predictive criteria, the system performs preliminary fixation of statistical information on tables that are most susceptible to performance issues, preventing degradation before it impacts the system.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If tables with high update frequency are identified for fixation, then performance degradation is prevented, but selection accuracy may be insufficient without considering record count

Engineering Contradiction:

Improveperformance stabilityVSAvoidtable selection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies merging by combining multiple selection criteria (update frequency and record count) into a comprehensive table selection approach. Instead of relying on a single metric, the system integrates both criteria to identify tables that should have their statistical information fixed, thereby improving the accuracy and reliability of the selection process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes parameter changes by using update frequency and record count as selection criteria to determine which tables should have their statistical information fixed. By changing the state of statistical information from dynamic to fixed based on these parameter thresholds, the system optimizes the balance between performance stability and monitoring efficiency.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250384023A1Information processing apparatus and information processing method

Publication Date: 2025.12.18 FUJITSU LTD

AI summary

A storage device stores the update frequency of statistical information acquired for each of a plurality of tables included in a database and the number of records in each of the plurality of tables. A processing unit determines, among the plurality of tables, a table whose statistical information has an update frequency that is greater than a first threshold and in which the number of records is greater than a second threshold, as a statistical information fixation target.