关键词: 分布式数据库, 并发控制, 数据持久化, 数据一致性, 高数据竞争负载

Abstract: To ensure high availability of data,modern NewSQL databases often create several copies of data so that it can be accessed from other copies in case one copy is not available.With multiple data copies,it is essential to consider data consistency between them.This means that the results should be the same when different clients read the same data at a particular moment.Therefore,a transaction processing mechanism is introduced.In the interactive transactional process with multiple write operations,each write operation must be performed on both the primary and backup copies of the data,since there are multiple copies.However,the primary and backup replicas are typically located on different machines,resulting in increased latency when writing to remote replicas,which in turn can ultimately lead to an increase in the processing latency of the entire transaction.In this paper,we present a collaborative data persistence scheme where the client caches the transaction write logs locally.When the transaction is finally committed,the client firstly persists the write logs of the transaction and sends the logs to the coordinator node of the transaction to allow the coordinator to distribute the log data,so as to achieve the purpose of the two cooperating in persistence of the transaction data.Experimental results show that in comparison to the synchronous persistence scheme,cooperative persistence scheme can not only reduce the latency of interactive transaction processing,but also improve the system limit throughput rate by roughly 38%.

Key words: Distributed database, Concurrency control, Data persistence, Data consistency, High-contention workload