Long Locks
LU 6.2 2PC protocols (PN) allow an application program to trade off network flows against duration of the commit operation, and therefore the length of time that resource locks are held (long locks). In the usual case, the subordinate sends the commit acknowledgment to the coordinator as soon as it has ensured that it has finished committing the transaction. If the coordinator enables the long-locks variation, the subordinate delays sending the commit acknowledgment until it sends the message begin ning the next transaction. Since the commit acknowledgment can be packaged in the same packet as the next-transaction data, this reduces the network flows by one at the cost of keeping the resources at the coordinator locked for a longer period. Note that LU 6.2 allows this variation only if the coordi nator will be in RECEIVE state at the end of the