Optimizing update instructions in hierarchically structured documents is provided. A pending update list including a first plurality of items is received. Each item of the first plurality of items describes an update to a hierarchically structured document. Each of one or more items of the first plurality of items is added to a subsumed update list having a second plurality of items. The subsumed update list is ordered based, at least in part, on a document order and on a target node of each of the second plurality of items. Subsume logic is applied to each of the one or more items based, at least in part, on the second plurality of items. Responsive to determining that subsume logic has been applied to each item of the first plurality of items, each of the second plurality of items of the subsumed update list is executed.