1. A computer-implemented method for calculating an undo retention in a database system, comprising: tracking at least one operation executing in the database system; selecting, by using a processor, a first instance-wide longest running operation from among tracked operations; broadcasting first information describing the first instance-wide longest running operation to other instances in the database system, wherein the act of broadcasting comprises communicating the first information to the other instances in the database system such that a system-wide longest running operation is obtained based at least in part upon the first information describing the first instance-wide longest running operation propagated to the other instances and other information describing one or more other instance-wide longest running operations propagated from the other instances through the database system; receiving second information describing a second instance-wide longest running operation; selecting either the first instance-wide longest running operation or the second instance-wide longest running operation as the system-wide longest running operation; calculating an undo retention for supporting the system-wide longest running operation; and storing the first information in a volatile or non-volatile computer-usable medium or displaying the first information on a display device.