It's not a lock in the sense that that is succeeds or fails immediatelly. It is a lock in the sense that it allows success only. Pesimistic lock usually means

It's not a lock in the sense that that is succeeds or fails immediatelly. It is a lock in the sense that it allows success only. Pesimistic lock usually means "maybe wait then success". In complex locking spaghetti it may mean deadlock. It may also mean wait then timeout. It may also mean wait then timeout then I don't know what actually happened, maybe success, maybe not.