Database Management System with Selective Cache Coherency
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Solution Overview
Problem
Managing in-memory databases on multicore processors is challenging due to high power consumption and bus contention when using cache coherency mechanisms across a large number of cores, which limits the number of cores available for use and degrades performance.
Innovation Solution
Implementing a database management system with a multicore processor that uses a shared memory with a cache coherency mechanism and a partitioned memory without cache coherency, allowing transaction worker threads to manage transaction states and database indexes in shared memory while partition manager threads handle database access actions in partitioned memory, enabling dynamic repartitioning and selective activation/disabling of cache coherence to balance performance and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cache coherency mechanism is activated on all cores, then data consistency is maintained, but power consumption increases and bus contention degrades performance
Solution Approach 1:
The patent applies local quality by enabling cache coherency mechanism selectively only for transaction worker threads that require data consistency, while disabling it for partition manager threads that do not require it. This localized application of cache coherency maintains data consistency where needed while reducing power consumption and bus contention where it is not needed, resolving the contradiction between reliability and energy usage.
2Reliability
If cache coherency mechanism is activated on all cores, then data consistency is maintained, but performance degrades due to bus contention
Solution Approach 1:
The patent enables cache coherency mechanism selectively only for transaction worker threads that require data consistency, while disabling it for partition manager threads. This localized approach maintains data consistency where required while eliminating unnecessary bus contention that degrades performance, thus resolving the contradiction between reliability and productivity.
3Reliability
If cache coherency mechanism is activated on all cores, then data consistency is maintained, but the number of available cores is limited
Solution Approach 1:
The patent applies cache coherency mechanism selectively to only those cores executing transaction worker threads that require data consistency, while leaving cores executing partition manager threads without cache coherency overhead. This increases the number of effectively available cores by removing unnecessary coherence constraints from threads that do not require them, while maintaining data consistency where needed.
4Use of energy by moving object
If cache coherency mechanism is disabled in partitioned memory, then power consumption is reduced and more cores are available, but data consistency may be compromised
Solution Approach 1:
The patent enables cache coherency mechanism selectively for transaction worker threads that access shared memory and require data consistency, while disabling it for partition manager threads accessing partitioned memory. This localized selective enabling maintains data consistency for threads that need it while reducing power consumption for threads that do not require consistency, resolving the contradiction between energy efficiency and reliability.
Data Source
AI summary
There is provided a database management system, comprising: a multicore processor, a shared memory, a partitioned memory, and a database engine adapted to execute at least one transaction worker thread managing transaction states and database indexes in the shared memory using a cache coherency mechanism, and execute at least one partition manager thread for handling database access actions submitted by the at least one transaction worker thread to access a database in the partitioned memory, the cache coherency mechanism being disabled in the partitioned memory; wherein the at least one transaction worker thread and the at least one partition manager thread are executed simultaneously on the multicore processor.