High-Peroformance Relational Data Processing

Currently, I am investigating what would it take to process relational SQL data at the rate of 100 Gbps - the rate at which modern networking and storage devices can serve data today. As a first step, I have investgiated the reading performance of file formats (JSON, Avro, Parquet, ORC, and Arrow). The finding are summaried in my blog post and our USENIX ATC 2018 paper.

Apache Crail (Incubating)

Crail is an open source user-level I/O architecture for the Apache data processing ecosystem designed from ground up for high-performance storage and networking hardware (40-100Gbps RDMA, flash, GPUs, etc). It involves groud-up design and implementation of multiple components and tools for Apache data processing ecosystem. More details can be found at https://crail.incubator.apache.org/.


Data center RPC or DaRPC is a Java library that provides ultra-low latency RPC for RDMA capable network interfaces. DaRPC is built on DiSNI. DaRPC source code is available https://github.com/zrlio/darpc.


DiSNI is a Java library for direct storage and networking access from userpace. It currently provides an RDMA interface. Support for other userpace storage and networking interfaces, such as DPDK or SPDK, are in planning. DiSNI source code is available at https://github.com/zrlio/disni.


SoftiWARP (siw) is a software iWARP kernel driver and user library for Linux. It implements the iWARP protocol suite (MPA/DDP/RDMAP, IETF-RFC 5044/5041/5040) completely in software, without requiring any dedicated RDMA hardware. SoftiWARP source code is available at https://github.com/zrlio/softiwarp.

Old projects


Distributed DRAM stores have become an attractive option for providing fast data accesses to analytics applications. To accelerate the performance of these stores, researchers have proposed using RDMA technology. RDMA offers high bandwidth and low latency data access by carefully separating resource setup from IO operations, and making IO operations fast by using rich network semantics and offloading. Despite recent interest, leveraging the full potential of RDMA in a distributed environment remains a challenging task.

RStore is a DRAM-based data store that delivers high performance by extending RDMA’s separation philosophy to a distributed setting. RStore achieves high aggregate bandwidth (705 Gb/s) and close-to-hardware latency on our 12-machine testbed. We developed a distributed graph processing framework and a Key-Value sorter using RStore’s unique memory-like API. The graph processing framework, which relies on RStore for low-latency graph access, outperforms state-of-the-art systems by margins of 2.6-4.2x when calculating Page Rank. The Key-Value sorter can sort 256 GB of data in 31.7 sec, which is 8x better than Hadoop TeraSort in a similar setting.


During the past decade, network and storage devices have undergone rapid performance improvements, delivering ultra-low latency and several Gbps of bandwidth. Nevertheless, current network and storage stacks fail to deliver this hardware performance to the applications, often due to the loss of IO efficiency from stalled CPU performance. While many efforts attempt to address this issue solely on either the network or the storage stack, achieving high-performance for networked-storage applications requires a holistic approach that considers both.

FlashNet is a software I/O stack that unifies high-performance network properties with flash storage access and management. FlashNet builds on RDMA principles and abstractions to provide a direct, asynchronous, end-to-end data path between a client and remote flash storage. The key insight behind FlashNet is to co-design the stack’s components (an RDMA controller, a flash controller, and a file system) to enable cross-stack optimizations and maximize IO efficiency. In micro-benchmarks, FlashNet improves 4kB network IOPS by 38.6% to 1.22M, decreases access latency by 43.5% to 50.4 µsecs, and prolongs the flash lifetime by 1.6-5.9x for writes. We illustrate the capabilities of FlashNet by building a Key-Value store, and porting a distributed data store that uses RDMA on it. The use of FlashNet’s RDMA API improves the performance of KV store by 2x, and requires minimum changes for the ported data store to access remote flash devices.

Jekyll theme inspired by researcher