MDX Sub-select Processing in Multidimensional Databases
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Solution Overview
Problem
Multidimensional database environments face challenges in efficiently processing queries with sub-select constructs, particularly in terms of query time and dynamic calculations, which can lead to unacceptable performance in security-sensitive and aggregation use cases.
Innovation Solution
The system supports sub-select constructs within Multidimensional Expressions (MDX) queries, where the inner sub-select is used to restrict the data space for the main query execution without being executed first, enabling partial aggregation calculations during data scanning, thus reducing query time and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the inner sub-select is executed before the main query in traditional multidimensional database systems, then the data space can be restricted for the main query, but the query time increases significantly due to sequential execution and dynamic calculations
Solution Approach 1:
The patent merges the execution of the inner sub-select and main query into a single kernel pass. Instead of executing the sub-select first and then the main query separately, the system combines both operations into one unified processing pass that simultaneously evaluates the sub-select conditions and performs the main query aggregation, eliminating the sequential execution overhead and dynamic calculation repetitions.
Solution Approach 2:
The system performs preliminary preparation by parsing and preparing the sub-select construct during query compilation, but defers actual data processing until the single kernel pass. The sub-select conditions are pre-processed and integrated into the main query execution plan, so that during the single pass through the data, both sub-select filtering and main query aggregation are accomplished without requiring preliminary sub-select execution.
2Reliability
If dynamic calculations are performed for sub-select constructs in traditional systems, then security-sensitive and aggregation use cases can be supported, but the calculation overhead reduces processing efficiency
Solution Approach 1:
The patent merges dynamic calculation operations into the single kernel pass by integrating sub-select evaluation and main query aggregation into one unified calculation process. The kernel simultaneously evaluates security conditions from the sub-select and performs aggregation calculations, eliminating the need for separate dynamic calculation phases and reducing overall computation overhead while maintaining security requirements.
Solution Approach 2:
The system ensures continuous useful action by performing both sub-select evaluation and main query aggregation in an uninterrupted single pass through the data. Rather than pausing for separate sub-select execution and then resuming for aggregation, the kernel continuously processes both operations simultaneously, maximizing processor utilization and eliminating idle computation time.
3Measurement precision
If multiple passes are used to process sub-select and main query separately, then processing can be thorough and accurate, but the number of passes increases query execution time
Solution Approach 1:
The patent merges multiple processing passes into a single kernel pass that simultaneously accomplishes sub-select evaluation, data filtering, and main query aggregation. The unified processing ensures that all necessary operations are performed in one thorough pass through the data, maintaining result accuracy while eliminating the time penalty of multiple sequential passes.
Data Source
AI summary
In accordance with an embodiment, described herein is a system and method for supporting queries having sub-select constructs in a multidimensional database computing environment. The system enables a sub-select construct to be provided as part of an input query, for example using a Multidimensional Expressions (MDX), or other type of query. The inner sub-select, specified by the input query, is not executed by the system before the main query, but is used to restrict the data space for execution of the main select. The approach to processing the sub-select enables support for security-sensitive or other types of aggregation use cases.