Back to the Future: Dynamic Hierarchical Clustering

We describe a new method for dynamically clustering hierarchical data which maintains good clustering within disk pages in the presence of insertions and deletions. This simple but eeective method, which we call Enc, encodes the insertion order of children with respect to their parents and concatenates the insertion numbers to form a compact key for the data. This compact key is stored only in the indexing structure and does not aaect the logical database schema. Experimental results show that our Enc method is very eecient for hierarchical queries and performs reasonably well for random access queries.