In the context of distributed database systems, explain the concept of distributed deadlock detection and resolution.

Explain the CAP theorem in the context of distributed databases and provide examples of how different systems prioritize consistency, availability, and partition tolerance.

Distributed database systems, like other distributed systems, have an issue with concurrency management, which is similar to the problem that other distributed systems have. Considering that pieces are not duplicated, is it required to impose concurrency management methods such as 2PL (Two-phase locking) on a system? Explain.

In stateless distributed systems, what considerations arise when handling "long-lived transactions" and maintaining data consistency?