Low-Latency Communication for Fast DBMS Using RDMA and Shared Memory

While hardware and software improvements greatly accelerated modern database systems' internal operations, the decades-old stream-based Socket API for external communication is still unchanged. We show experimentally, that for modern high-performance systems networking has become a performance bottleneck. Therefore, we argue that the communication stack needs to be redesigned to fully exploit modern hardware - as has already happened to most other database system components.We propose L5, a high-performance communication layer for database systems. L5 rethinks the flow of data in and out of the database system and is based on direct memory access techniques for intra-datacenter (RDMA) and intra-machine communication (Shared Memory). With L5, we provide a building block to accelerate ODBC-like interfaces with a unified and message-based communication framework. Our results show that using interconnects like RDMA (InfiniBand), RoCE (Ethernet), and Shared Memory (IPC), L5 can largely eliminate the network bottleneck for database systems.