Optimizing Hierarchical Access in OLAP Environment
Abstract—In Online Analytic Processing (OLAP) deployments, different users, lines of businesses and business units often create,adhoc,aggregation,hierarchies,tailor-made for specific reporting or analytical applications. As a result, a large number of these application,specific hierarchies,accumulate,over time. System,administrators,typically are,not,able to optimize,all these hierarchical,accesses,by hand,due,to the large number of hierarchies. However, many optimization opportunities exist due to the significant amount,of overlap between,some,hierarhies. In this paper, we sketch a novel method for optimizing OLAP aggregation,queries using precomputed,aggregates on other over- lapping hierarchies. Our method,detects common,sub-structures among,hierarchies and provides,a rewriting algorithm,to exploit any precomputations,on these shared,sub-structures.