Materialized Table Hash Verification for Query Processing

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Solution Overview

Problem

The use of materialized tables in query processing is inefficient due to the resource-intensive process of determining whether the content has changed since materialization, leading to temporal delays in processing queries.

Innovation Solution

A method that computes a hash value for portions of a materialized table and compares it to a pre-stored encoding, allowing for the reuse of the table if unchanged, and re-materialization if changed, thereby optimizing query processing by reducing the need for full re-materialization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If materialized tables are used to cache query results, then query processing speed is improved, but determining whether content has changed since materialization becomes resource-intensive and causes temporal delays

Engineering Contradiction:
Improvequery processing speedVSAvoidtemporal delays in query processing
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent segments the content verification process into two distinct parts: structural verification (using hash values of table schemas) and content verification (comparing actual data content). This segmentation allows the system to quickly verify structural integrity without always performing full content comparisons, thereby reducing the resource intensity and temporal delays associated with determining whether materialized table content has changed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by pre-computing and storing hash values of materialized table structures at the time of materialization. These pre-stored hash values serve as quick reference markers that enable rapid structural verification without requiring full content re-evaluation, thus improving query processing speed while minimizing the time and resources needed for change detection.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If full re-materialization is performed whenever content change is detected, then data accuracy is maintained, but computational load and processing time increase significantly

Engineering Contradiction:
Improvedata accuracyVSAvoidquery execution efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies partial action by implementing incremental re-materialization strategies. Instead of always performing full re-materialization when changes are detected, the system can perform partial re-materialization only on the affected portions of the materialized table. This approach maintains data accuracy for changed portions while avoiding the excessive computational load and time consumption of complete re-materialization, thus improving overall query execution efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent utilizes parameter changes by introducing hash value comparison as a new parameter for determining whether re-materialization is necessary. By comparing hash values of the materialized table structure against stored reference values, the system can make informed decisions about re-materialization needs. This parameter-based approach ensures data accuracy by verifying structural integrity while optimizing productivity by avoiding unnecessary full re-materialization operations.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11841841B2Stand in tables
Publication Date: 2023.12.12 GOOGLE LLC
  • US11841841B2 patent drawing
  • US11841841B2 patent drawing

AI summary

A method for pre-utilizing tables before refresh includes selecting a query for execution in a data analytics application and identifying a table specified by the query, for instance a materialized table. Another operation includes computing an encoding, such as a hash value, for at least one portion of the identified table. Another operation includes comparing the computed encoding to a pre-stored encoding for the at least one portion of the identified table. On the condition that the computed encoding is identical to the pre-stored encoding, the operations include utilizing the identified table in executing the query in lieu of re-materializing the identified table. Otherwise, on the condition that the computed encoding differs from the pre-stored encoding, the operations include re-materializing the identified table before returning the results of the query.