Efficient Algorithm for determining the Optimal Execution Strategy for Path Queries in OODBS

To select an optimal query evaluation strategy for a path query in an object-oriented database system one has to exploit the available index structures on the path. In a database with a large database schema many alternative strategies have to be considered for the evaluation of a path query by choosing from a large set of available indices, which can make the selection of the optimal strategy expensive. We give an algorithm that finds the optimal strategy for evaluating a path query with time complexity independent of the set of indices available in the database. The algorithm considers all possible forward and backward traversal strategies and has time complexity O(n2) in the path length n. Incorporating this algorithm into the query optimization for object-oriented database management systems can improve the response time of the system, by optimizing an equally important and frequent type of queries with high efficiency.