Optimal Operator Placement in Distributed Database Query Processing

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Solution Overview

Problem

Greedy algorithms in distributed database management systems often fail to find optimal node locations for operator placement, leading to suboptimal solutions in terms of global minimum costs for database operations.

Innovation Solution

The approach involves calculating and comparing multiple sub-plans for distributing node locations of operators across multiple nodes to determine the optimal plan with the lowest total minimum global cost, considering child table transfer counts and network configurations, and pruning sub-plans that exceed optimal costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a greedy algorithm is used to determine node locations for operator placement, then the computational time is reduced and a solution is obtained quickly, but the solution quality deteriorates and global minimum costs cannot be achieved

Engineering Contradiction:
Improvecomputational timeVSAvoidsolution quality
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

The patent segments the operator placement problem into multiple independent sub-problems, where each operator is placed on a node independently based on its own cost analysis. This segmentation allows the system to avoid the computational complexity of evaluating all possible placements while still achieving near-optimal results by making localized optimal decisions for each operator.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by optimizing the placement of each operator individually based on its specific characteristics and requirements. Each operator's placement is determined by calculating the minimum cost for that specific operator-node combination, considering factors like data locality and network topology, rather than applying a uniform global optimization approach.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If multiple sub-plans are evaluated to find the optimal operator placement, then the solution quality improves and global minimum costs are achieved, but the device complexity increases due to multiple plan evaluations

Engineering Contradiction:
Improvesolution qualityVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by evaluating only the necessary subset of sub-plans required to achieve optimal operator placement. Instead of exhaustively evaluating all possible operator placement combinations, the system evaluates sub-plans incrementally, adding operators one at a time and pruning sub-plans that exceed optimal costs, thus reducing the overall computational complexity while maintaining solution quality.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent uses preliminary action by pre-calculating and storing cost metrics for operator placements before actual query execution. The system pre-evaluates the cost of placing operators on different nodes based on data location and network topology, and uses these pre-computed values to quickly determine optimal placements during query processing, avoiding repeated complex calculations.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If operator placement is optimized for minimum cost, then the productivity of distributed query processing improves, but the ease of operation deteriorates due to complex placement calculations

Engineering Contradiction:
Improvequery processing efficiencyVSAvoidoperational simplicity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent applies self-service by enabling the distributed query optimizer to automatically determine optimal operator placements without requiring manual intervention. The system autonomously evaluates cost metrics, selects optimal node locations for operators, and generates execution plans, thereby improving query processing efficiency while abstracting the complexity of placement calculations from the user.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses parameter changes by dynamically adjusting operator placement decisions based on varying query parameters and system state. The optimizer changes placement parameters such as node selection and data distribution strategies according to the specific characteristics of each query, allowing the system to adapt to different operational scenarios while maintaining optimality.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9892163B2Optimal operator placement for distributed query processing
Publication Date: 2018.02.13 SAP SE
  • US9892163B2 patent drawing
  • US9892163B2 patent drawing
  • US9892163B2 patent drawing

AI summary

Total global minimum costs can be determined for multiple sub-plans for completing a multi-operation database process to be performed in a distributed database management system that includes a plurality of nodes. The multiple sub-plans can include different distributions of node locations of a plurality of operators among the plurality of nodes. An optimal plan having a lowest total minimum global cost can be selected from the multiple sub-plans.