Hybrid^2-Index Structures for Main Memory Databases

该项目的目标是加快数据库管理系统（DBMS）的索引访问，以提高整体性能。由于索引访问是数据库查询所有后续处理步骤的起点，因此快速的索引访问是DBMS获得上级总体性能的关键。为了加快索引访问速度，我们提出研究和开发新的硬件/软件索引结构，实现结构混合索引，即，静态和动态索引的组合，在由CPU和FPGA或GPU作为硬件加速器组成的混合共享存储器系统架构上。到目前为止，在文献中还没有考虑这种混合^2-索引，使得当前混合共享存储器系统架构的可能性没有以最佳方式被利用。由于CPU和硬件加速器之间的通信成本的降低，许多现有的设计规则，利用硬件加速器必须重新考虑，特别是考虑到由硬件加速器接管的任务的复杂性，因此在这个项目中，我们将研究哪些以及如何静态和动态索引结构可以实现在一个高效的方式与高性能的混合系统。此外，我们将研究如何通过动态交换硬件加速器上使用的索引结构来对不断变化的访问模式做出反应。我们期待新的，自适应的结构和硬件混合索引结构，显着提高性能的DBMS中的索引访问相比，现有的传统系统。

The goal of the project is to speed up index accesses of database management systems (DBMS) in order to improve the total performance. As index accesses are starting points for all succeeding processing steps of database queries, fast index accesses are the key to a superior total performance of DBMS. For the purpose of speeding up index accesses we propose to investigate and develop new hardware-/software index structures, which realize structure-hybrid indexes, i.e., the combination of static and dynamic indexes, on hybrid shared-memory system architectures consisting of a CPU and an FPGA or GPU as hardware accelerator. Such hybrid^2-indexes are not considered so far in literature, such that the possibilities of current hybrid shared-memory system architectures are not utilized in an optimal way. Because of the reduction of the communication costs between CPU and hardware accelerator many existing design rules for utilizing hardware accelerators must be rethought, especially concerning the complexities of tasks taken over by the hardware accelerators.Within this project we will hence research on which and how static and dynamic index structures can be realized in an efficient way with high performance on hybrid systems. Furthermore, we will investigate how to react on changing access patterns by dynamically swapping used index structures on the hardware accelerators. We expect novel, adaptive structure- and hardware-hybrid index structures, which significantly improve the performance of index accesses in DBMS in comparison to existing traditional systems.