In a data storage and retrieval system wherein data is stored and retrieved in pages, said data comprising connected nodes arranged such that each page stores only complete nodes, said connected nodes being connected via a plurality of overlapping tree structures, a method of minimizing page retrieval in the face of changing relationships between nodes comprising: selecting at least two of said overlapping tree structures; incrementally adjusting a page node structure dynamically based on real time workload, separately according to each selected tree structure, to form modified partitions for each tree structure, each modified partition being so as to minimize page faults; for each modified partition calculating a modification gain to indicate which partition has provided a greater minimization of page faults; and selecting the tree structure and modified partition corresponding to the best modification gain.