HelperCoreDB: Exploiting multicore technology to improve database performance

Due to limitations in the traditional microprocessor design, such as high complexity and power, all current commercial high-end processors contain multiple cores on the same chip (multicore). This trend is expected to continue resulting in increasing number of cores on the chip. While these cores may be used to achieve higher throughput, improving the execution of a single application requires careful coding and usually results in smaller benefit as the scale of the system is increased. In this work we propose an alternative way to exploit the multicore technology where certain cores execute code which indirectly improves the performance of the application. We call this approach the Helper Core approach. The main contribution of this work is the proposal and evaluation of HelperCore_DB, a Helper Core designed to improve the performance of database workloads by performing efficient data prefetching. We validate the proposed approach using a HelperCore_DB implementation for the PostgreSQL DBMS. The approach is evaluated with native execution on a dual core processor system using the standard TPC-H benchmark. The experimental results show a significant performance improvement specially considering that the baseline system is a modern optimized processor that includes advanced features such as hardware prefetching. In particular, for the 22 queries of TPC-H, our approach achieves a large reduction of the secondary cache misses, 75% on average, and an improvement in the execution time of up to 21.5%.