Patent ID: 7877379
Filing Date: 2011-01-25
Classification: G06F,Y10S

Abstract:
1. A computer-implemented method of generating an execution plan for a query, comprising: establishing an expensive expression in the query; wherein establishing the expensive expression includes one or more of: generating a first execution plan for the query in which an operation evaluating the expensive expression occurs no later than a non-empty set of operations that do not evaluate the expensive expression; generating one or more equivalent execution plans for the query, wherein generating the one or more equivalent execution plans includes generating, in response to said establishing the expensive expression in the query, an execution plan in which the operation evaluating the expensive expression occurs after the non-empty set of operations not evaluating the expensive expression; and choosing, based on a set of criteria, a particular execution plan from the first execution plan and the one or more equivalent execution plans; wherein the method is performed by one or more computing devices.