Task Scheduling for GPU Accelerated Hybrid OLAP Systems with Multi-core Support and Text-to-Integer Translation

OLAP (On-Line Analytical Processing) is a powerful method for analyzing the excessive amount of data related to business intelligence applications. OLAP utilizes the efficient multidimensional data structure referred to as the OLAP cube to answer multi-faceted analytical queries. As queries become more complex and the dimensionality and size of the cube grows, the processing time required to aggregate queries increases. In this paper, we are proposing: (1) a parallel implementation of MOLAP cube using OpenMP, (2) a text-to-integer translation method to allow effective string processing on GPU, and (3) a new scheduling algorithm that support these new features. To be able to process string queries on the GPU, we are introducing a text-to-integer translation method which works with multiple dictionaries. The translation is necessary only for the GPU side of the system. To support the translation and parallel CPU implementation, a new scheduling algorithm is proposed. The scheduler divides multi-core processor(s) of a shared memory system into a processing partition and a preprocessing (or translation) partition. The performance of the new system is evaluated. The text-to-integer translation adds a new vital functionality to our system, however it also slows down the GPU processing by 7% when compare to original implementation without string support. The performance measurements indicate that due to the parallel implementation, the processing rate of the CPU partition improves from 12 to 110 queries per second. Moreover, the CPU partition is now able to process OLAP cubes of size 32 GB at rate of 11 queries per second. The total performance of the entire hybrid system (CPU + GPU) increased from 102 to 228 queries per second.