Selective Skipping of Dictionary Scans and Index Lookups
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Solution Overview
Problem
Traditional database management systems incur inefficiencies due to the unnecessary execution of dictionary scans and index lookups during query processing, which wastes technical resources and increases query latency.
Innovation Solution
A set of pipelines is introduced that enables selective skipping of dictionary scans and index lookups by executing these operations only when necessary, utilizing conjunction operators in both the initialization and index lookup pipelines to determine if scans/lookups can be inhibited.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dictionary scans and index lookups are always executed during query processing, then complete query results can be obtained, but technical resources are wasted and query latency increases
Solution Approach 1:
The system performs preliminary evaluation of predicates through initialization pipelines before executing the full query processing. By evaluating predicates in advance and determining which ones will return empty results, the system can skip unnecessary dictionary scans and index lookups, thus improving efficiency while maintaining result completeness through selective execution.
2Measurement precision
If all predicates are processed through complete pipeline execution, then accurate query results are ensured, but unnecessary operations increase processing time
Solution Approach 1:
The system implements selective skipping of pipeline stages based on preliminary evaluation results. When a predicate is determined to return an empty result set during initialization, the corresponding dictionary scan and index lookup stages are skipped entirely. This rushing through of unnecessary operations reduces query latency while maintaining accuracy by only executing operations that will contribute to the final result.
3Reliability
If dictionary scans are performed for all predicates, then value identifiers are obtained for accurate filtering, but system resources are unnecessarily consumed
Solution Approach 1:
The system extracts and evaluates predicates separately in initialization pipelines before committing to full processing. By taking out the evaluation step and performing it preliminarily, the system can identify predicates that will yield empty results and exclude them from subsequent resource-intensive dictionary scans and index lookups, thus reducing technical resource consumption while maintaining evaluation accuracy for the remaining predicates.
Data Source
AI summary
Methods, systems, and computer-readable storage media for a set of pipelines that enable selective skipping of dictionary scans and/or index lookups when processing queries in database management systems, such that dictionary scans and/or index lookups are only executed when needed, eliminating unnecessary execution of dictionary scans and/or index lookups to improve efficiency of the database system in terms of reducing load on technical resources and improve query performance by reducing latency in returning query results.