System and method for updating a data structure are disclosed. In one embodiment, the method includes providing a data structure that includes a hierarchically arranged set of nodes and branches, and each node has two or less branches, retrieving a first data entry in the data structure via a first node in response to a first data access request, modifying the data structure to generate a first intermediate data structure that keeps the first node and creates a duplicate of the first node, and retrieving a second data entry in the data structure via the duplicate of first node in response to a second data access request. By maintaining at least the first node or a duplicate of the first node during a rebalancing operation of the data structure, the disclosed method supports accessing data entries associated with the first node during the rebalancing operation and therefore improves system performance.