GTX: A Write-Optimized Latch-free Graph Data System with Transactional Support -- Extended Version

TL;DR

GTX is a novel main-memory graph data system that provides high write throughput and low-latency analytics by eliminating vertex lock contention and supporting ACID transactions, especially excelling in write-heavy workloads.

Contribution

GTX introduces an adaptive delta-chain locking protocol and latch-free storage, enabling high-performance concurrent updates and analytics in main-memory graph systems.

Findings

GTX achieves up to 11x higher transaction throughput in write-heavy workloads.

GTX maintains competitive read performance for analytical workloads.

GTX effectively eliminates vertex lock contention, improving update efficiency.

Abstract

This paper introduces GTX, a standalone main-memory write-optimized graph data system that specializes in structural and graph property updates while enabling concurrent reads and graph analytics through ACID transactions. Recent graph systems target concurrent read and write support while guaranteeing transaction semantics. However, their performance suffers from updates with real-world temporal locality over the same vertices and edges due to vertex-centric lock contentions. GTX has an adaptive delta-chain locking protocol on top of a carefully designed latch-free graph storage. It eliminates vertex-level locking contention, and adapts to real-life workloads while maintaining sequential access to the graph's adjacency lists storage. GTX's transactions further support cache-friendly block level concurrency control, and cooperative group commit and garbage collection. This combination of features ensures high update throughput and provides low-latency graph analytics. Based on experimental evaluation, in addition to not sacrificing the performance of read-heavy analytical workloads, and having competitive performance similar to state-of-the-art systems, GTX has high read-write transaction throughput. For write-heavy transactional workloads, GTX achieves up to 11x better transaction throughput than the best-performing state-of-the-art system.