Detection Arcs for Deadlock Management in Nested Transactions and their Performance

In this paper, we address deadlock management in nested transactions. In our strategy, deadlocks are detected through the occurrence of cycles in a waits-for graph (WFG). However, the process of looking for cycles in the WFG considering all its nodes and edges can be very time-consuming. To accelerate this process, we propose the detection arcs. In essence, a detection arc represents a higher level abstraction embodying a hidden waiting relation between two transactions that is caused by a lock wait. Thus, the deadlock detection process needs to traverse only a minimal subset of the WFG’s edges when it is started, the set of detection arcs. Therefore, the overall performance of deadlock management is improved, as confirmed by our performance measurements.