Distributed Query Plan Checking for Execution Deadlock Prevention
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Solution Overview
Problem
Database management systems face challenges in optimizing query performance due to potential execution deadlocks in distributed query execution plans across multiple computing nodes, which can lead to inefficient resource utilization and prolonged response times.
Innovation Solution
A database management system generates reduced representations of query execution plans for each node, merges these representations into global pipelines, and performs deadlock checks to prevent execution if a deadlock is detected, thereby ensuring efficient execution without cyclic dependencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If distributed query execution plans are implemented across multiple computing nodes, then query processing capability and throughput are improved, but execution deadlocks occur leading to resource utilization degradation
Solution Approach 1:
The system performs deadlock detection and validation before executing the distributed query execution plan. By analyzing the global pipelines and checking for cyclic dependencies in advance, the system prevents deadlocks from occurring during actual query execution, thus maintaining both high productivity and reliability
Solution Approach 2:
The patent introduces an intermediary validation mechanism that acts as a mediator between query plan generation and execution. This intermediary layer analyzes the distributed execution plan for potential deadlocks using global pipeline analysis and cyclic dependency detection, allowing the system to filter out problematic plans before they cause execution failures
2Reliability
If comprehensive deadlock checks are performed on distributed execution plans, then execution reliability is improved, but system complexity and validation time increase
Solution Approach 1:
The deadlock detection mechanism is segmented into distinct analytical components: global pipeline construction from distributed execution plans, cyclic dependency detection algorithms, and validation rule applications. This segmentation allows each component to handle specific aspects of deadlock prevention independently, reducing overall system complexity while maintaining comprehensive coverage
Solution Approach 2:
The system creates a simplified copy or model of the distributed execution plan in the form of global pipelines for analysis purposes. By working with this abstracted representation rather than the full complex execution plan, the validation mechanism can efficiently detect deadlocks without being overwhelmed by the complexity of the original system
Data Source
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AI summary
A database management system receives a first query execution plan to be executed on a plurality of computing nodes. The database management system determines whether the first query execution plan would result in an execution deadlock by performing the following three steps. First, the database management system generates a reduced representation of a portion of the first query execution plan corresponding to each computing node of the plurality of computing nodes. Second, the database management system merges the reduced representations of a plurality of portions of the first query execution plan into a set of global pipelines. Third, the database management system performs at least one deadlock check on the set of global pipelines. The database management system prevents execution of the first query execution plan responsive to the at least one deadlock check returning an error.