In-memory transactional data girds, often referred to as NoSQL data grids demand high concurrency for scalability and high performance in data-intensive applications. As an alternative concurrency control model, distributed transactional memory (DTM) promises to alleviate the difficulties of lock-based distributed synchronization. However, if a transaction aborts, DTM suffers from additional communication delays to remotely request and retrieve all its objects again, resulting in degraded performance. To avoid unnecessary aborts, the multi-versioning (MV) model of using multiple object versions in DTM can be considered. MV transactional memory inherently guarantees commits of read-only transactions, but limits concurrency of write transactions. We present a new transactional scheduler, called partial rollback-based transactional scheduler (or PTS), for a multi-versioned DTM model. The model supports multiple object versions to exploit concurrency of read-only transactions, and detects conflicts of write transactions at an object level. Instead of aborting a transaction, PTS assigns backoff times for conflicting transactions, and the transaction is rolled-back partially. We implemented PTS on Infinispan, and conducted comprehensive experimental studies on no and partial replication models. Our implementation reveals that PTS improves transactional throughput over MV-Transactional Forwarding Algorithm without PTS and a scalable one-copy serializable partial replication protocol (SCORe) by as much as 2.4× and 1.3×, respectively.

内存中的事务数据网格（通常称为NoSQL数据网格）要求高并发性，以便在数据密集型应用程序中实现可伸缩性和高性能。作为一种可选的并发控制模型，分布式事务内存（DTM）有望减轻基于锁的分布式同步的困难。但是，如果事务中止，DTM会遭受额外的通信延迟，从而无法远程请求并再次检索其所有对象，从而导致性能下降。为了避免不必要的中止，可以考虑在DTM中使用多个对象版本的多版本（MV）模型。MV事务内存从本质上保证了提交只读事务，但限制了写事务的并发性。我们提出了一种新的事务调度程序，称为基于部分回滚的事务调度程序（或PTS），用于多版本DTM模型。该模型支持多个对象版本，以利用只读事务的并发性，并在对象级别检测写事务的冲突。PTS不会中止事务，而是为冲突的事务分配退避时间，并且事务会部分回滚。我们在Infinispan上实施了PTS，并对无复制和部分复制模型进行了全面的实验研究。我们的实现表明，与不带PTS的MV事务转发算法和可伸缩的一副本可序列化部分复制协议（SCORe）相比，PTS的事务吞吐量分别提高了2.4倍和1.3倍。并在对象级别检测写事务冲突。PTS不会中止事务，而是为冲突的事务分配退避时间，并且事务会部分回滚。我们在Infinispan上实施了PTS，并针对无复制和部分复制模型进行了全面的实验研究。我们的实现表明，与不带PTS的MV事务转发算法和可伸缩的单副本可序列化部分复制协议（SCORe）相比，PTS的事务吞吐量分别提高了2.4倍和1.3倍。并在对象级别检测写事务冲突。PTS不会中止事务，而是为冲突的事务分配退避时间，并且事务会部分回滚。我们在Infinispan上实施了PTS，并针对无复制和部分复制模型进行了全面的实验研究。我们的实现表明，与不带PTS的MV事务转发算法和可伸缩的单副本可序列化部分复制协议（SCORe）相比，PTS的事务吞吐量分别提高了2.4倍和1.3倍。