Natto: Providing Distributed Transaction Prioritization for High-Contention Workloads

This paper introduces Natto, a geo-distributed database system that supports transaction prioritization. Instead of having each shard process transactions in their arrival order, Natto leverages network measurements to estimate the transaction arrival time at each shard, and assigns a timestamp to the transaction based on its arrival time to the furthest shard. These timestamps establish a global ordering of transactions, and introduces opportunities to selectively abort pending low-priority transactions that conflict with a high-priority transaction, or even preempt transactions that are already partially prepared. Our experiments on both Microsoft Azure and a local cluster show that Natto's tail latency for high-priority transactions are significantly lower than the tail latencies of Carousel and TAPIR, which are the current state-of-the-art in geo-distributed transaction processing systems.