A deadlock that is detected but is not really a deadlock is called a phantom deadlock. In distributed deadlock detection, information about wait-for relationships between transactions is transmitted from one server to another. If there is a deadlock, the necessary information will eventually be collected in one place, and a cycle will be detected. As this procedure will take some time, there is a chance that one of the transactions that holds a lock (see U above) will have released it, in which case the deadlock will no longer exist.