A processing system, computer program product, and methods for maintaining consistent values of objects in two or more stores. A method includes a data store associating an updated-version-request-time for each object of a plurality of objects, where each object of the plurality of objects resides on a respective another data store. The data store maintains a data structure ordering the plurality of objects by updated-version-request-times. The data store periodically examines the data structure to read updated-version-request-times. The data store makes a decision to request an updated version of an object belonging to the plurality of objects based on an updated-version-request-time of the object. The data structure can be a balanced tree.