(1) An optimization that cuts the number of two-phase commit flows to one agent in half by leaving the last agent out of the first phase of the commit process and giving the last agent the commit decision during the second phase. An initiator or last agent can use this optimization with only one of its subordinates, which is called the optimized last agent (or simply the last agent).
(2) An optimized commit flow for either presumed-nothing or presumed-abort protocols in which the last agent, or final participant, becomes the commit coordinator. This flow saves at least one message.