1. A method for execution by a processing module of a computer of a multiple computer dispersed storage network (MCDSN) that stores a plurality of data objects, the method comprises: determining to modify a distributed index structure by creating or modifying a data index key that identifies a data object based on an attribute of a first attribute category of a plurality of attribute categories, wherein the distributed index structure includes a hierarchical ordering of a root index node, a plurality of index nodes, and a plurality of leaf nodes, wherein a leaf node of the plurality of leaf nodes includes data fields indicating leaf node information, sibling node information that indicates whether or not another leaf node of the plurality of leaf nodes qualifies as a sibling node to the leaf node of the plurality of leaf nodes, and sibling node identification that identifies the another leaf node of the plurality of leaf nodes when the another leaf node of the plurality of leaf nodes qualifies as a sibling node to the leaf node of the plurality of leaf nodes, and data information regarding a plurality of data objects, and wherein the data information includes, for a data object of the plurality of data objects, a unique data index key to identify the data object; identifying a particular leaf node of the plurality of leaf nodes based on the attribute and the data object; retrieving one or more sets of encoded leaf node slices from a set of dispersed storage (DS) units of the MCDSN; receiving the particular leaf node from the one or more sets of encoded leaf node slices; adding or modifying the data index key in the particular leaf node in accordance with an ordering of attributes of the first attribute category to produce an updated leaf node; encoding the updated leaf node in accordance with a dispersed storage error coding function to produce one or more sets of encoded updated leaf node slices; and outputting the one or more sets of encoded updated leaf node slices to the set of DS units for storage therein.