The Serial Safety Net

Abstract

Concurrency control (CC) algorithms must trade off strictness for performance, with serializable schemes generally paying high cost---both in runtime overhead such as contention on lock tables, and in wasted efforts by aborting transactions---to prevent anomalies. We propose the serial safety net (SSN), a serializability-enforcing certifier for modern hardware with substantial core count and large main memory. SSN can be applied with minimal overhead on top of various CC schemes that offer higher performance but admit anomalies, e.g., snapshot isolation and read committed. We demonstrate the efficiency, accuracy and robustness of SSN using a memory-optimized OLTP engine with different CC schemes. We find that SSN is a promising approach to serializability with low abort rates and robust performance for various workloads.