Archie: A Speculative Replicated Transactional System

We present Archie, a high performance fault-tolerant trans-actional system. Archie complies with the State Machine Approach, where the transactional state is fully replicated and total ordered transactions are executed on the repli-cas. Archie avoids the serial execution after transactions get ordered, which is the typical bottleneck of those pro-tocols, by anticipating the work and using speculation to process transactions in parallel, enforcing a predefined or-der. The key feature of Archie is to avoid any non-trivial operation to perform post total order’s notification, in case the sequencer node remains stable (only a single timestamp increment is needed for committing a transaction). This ap-proach significantly shortens the transaction’s critical path. The contention of speculative execution is always kept lim-ited by activating a fixed number of transactions at a time. A comprehensive evaluation, using three competitors and three well known benchmarks, shows that Archie outper-forms competitors in all medium/high contention scenarios