Tenderex: Tentative Deterministic Request Execution for State-Machine Replication

• Applicant: Professor Dr.-Ing. Franz J. Hauck
• Subject Area: Security and Dependability, Operating-, Communication- and Distributed Systems
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 565683772

State-machine replication is a promising approach to fault-tolerant services. It requires deterministic execution of incoming requests. Many deterministic multithreading approaches have been developed to increase throughput and reduce latency. So far, there is no comprehensive comparison of these approaches. This project will investigate new approaches based on software-transactional memory. This allows for speculative and abortable executions. First, an approach has to be developed that considers the entire request as a transaction. Second, in an extension we use traditional locking information to run smaller parts of the request execution as abortable transaction so that in case of conflicts not the entire request has to be aborted. Further, tapping the underlying consensus protocol at an early stage allows for speculation on the request order and can decrease latency and increase throughput. However in worst case request executions have to be aborted and re-executed. The Tenderex project will evaluate and compare existing and newly developed approaches on the basis of two practical applications, YCSB and GraphQL. Further, microbenchmark are supposed to highlight individual behaviour of the approaches in corner cases.

• DFG Programme: Research Grants