Patent ID: 7647280
Filing Date: 2010-01-12
Classification: G06F,G06Q

Abstract:
1. A method for optimizing processing of a request, the request including one or more predicates, each predicate referencing one or more relations, the method including: the computer-implemented steps of: identifying the relations in the request; identifying one or more access paths for each relation; identifying the predicates in the request; for each predicate, associating the predicate with the one or more access paths identified for the one or more relations referenced in the predicate; estimating costs of executing the predicate using the one or more access paths associated with the predicate; and for at least one access path for which a cost was estimated, determining that a stored actual access path cost for the access path exists, and, in response, substituting the stored actual access path cost for the estimated access path cost, the stored actual access path cost for the access path being a measured cost of executing the predicate using the access path; for each predicate, for each relation referenced in the predicate, selecting an access path from among the one or more access paths associated with the predicate; executing the request using the selected access paths for the predicates, measuring an actual cost of executing the predicates in the request; and storing the measured actual costs as actual access path costs.