Is distributed locking harder?

摘要

We examine the problem of determining whether a set of locked transactions, accessing a distributed database, is guaranteed to produce only serializable schedules. For a pair of transactions we prove that this concurrency control problem (which is polynomially solvable for centralized databases) is in general coNP-complete. We employ a new graph-theoretic technique and provide an efficient test for the special case of databases distributed between two sites only.