TM-Stream: An STM framework for distributed event stream processing

We extend DSTM2 with a combination of two techniques: First, we applied speculative dependencies between transactions, as first introduced in. Specifically, transactions may read data of earlier transactions that have completed their execution, but are not yet committed. This is the case, for instance, when transactions have to commit in a certain order and must wait for the completion of earlier transactions to detect possible conflicts (e.g., in stream processing systems). Second, we expand speculation to distributed settings, by allowing not yet committed transactions to trigger execution of other speculative transactions on a remote machine. We use a simple notification mechanism to commit or abort remote speculative transactions once the outcome of all the transactions they depend on is known. In this paper we describe our extensions to the DSTM2 framework to enable distributed speculation and evaluate their performance on a simple distributed application.