A distribute deadlock detection and resolution algorithm using agents

Deadlock is an intrinsic bottleneck in Distributed Real-Time Database Systems (DRTDBS). Deadlock detection and resolution algorithms are important because in DRTDBS, deadlocked transactions are prone to missing deadlines. We propose an Agent Deadlock Detection and Resolution algorithm (ADCombine), a novel framework for distributed deadlock handling using stationary agents, to address the high overhead suffered by current agent-based algorithms. We test a combined deadlock detection and resolution algorithm that enables the Multi Agent System to adjust its execution based on the changing system load, and that selects its victim transactions more judiciously. We demonstrate the advantages of ADCombine over existing algorithms that use agents or traditional edge-chasing through simulation experiments that measure overhead and performance under a widely varying of experimental conditions.deadlockdistribute real-time database systemsdrtdbsalgorithmmulti agent syste

Replication and Nested Transactions in the Eden Distributed System

Hardware redundancy in distributed systems offers the potential for increased availability and performance, but this requires software support if the full potential is to be realized. We have designed and implemented two mechanisms for such support. The first provides crash-resistant resources, replicated transparently and consistently to increase the availability of distributed data. To update multiple copies despite down nodes, we have introduced the Regeneration method used in the implementation of a replicated system directory. Regeneration restores inaccessible copies elsewhere in the network, maintains the availability of resources, and adapts to configuration changes. The second mechanism is a systell1 supporting nested transactions, which can manage the complex failure modes in a distributed system, synchronize concurrent resource access internal to applications, and facilitate safe module composition. In the tree-structured nesting, each transaction has a Transaction Manager (TM), responsible for the concurrency control and crash recovery of its subtransactions. Many concurrency control and recovery techniques can be combined in this TM Tree design framework. We chose locking and versions for the first implementation. Using Eden objects and the replicated directory, our nested transactions provide consistent concurrent access 10 location-independent, crash- resistant resources. In summary, the principal contributions of this research are the Regeneration method and the TM Tree framework. Regeneration uses the separation of hardware repair from data restoration to increase replicated data availability. TM tree composes existing techniques to derive many difficult designs for nested transaction. Both have been proven in the design and implementation of actual systems

D7.5 FIRST consolidated project results

The FIRST project commenced in January 2017 and concluded in December 2022, including a 24-month suspension period due to the COVID-19 pandemic. Throughout the project, we successfully delivered seven technical reports, conducted three workshops on Key Enabling Technologies for Digital Factories in conjunction with CAiSE (in 2019, 2020, and 2022), produced a number of PhD theses, and published over 56 papers (and numbers of summitted journal papers). The purpose of this deliverable is to provide an updated account of the findings from our previous deliverables and publications. It involves compiling the original deliverables with necessary revisions to accurately reflect the final scientific outcomes of the project