US Patent 7840556 Managing performance of a database query

Provided are, among other things, systems, methods and techniques for processing database queries, such as the following. A current database query to be executed is obtained, and a plan for executing the current database query is generated. A cluster that includes at least one previously executed database query is identified, based on similarity of the plan for executing the current database query to execution-plan information representing the cluster. Then, a query-execution characteristic is assigned to the current database query based on corresponding characteristic information representing the cluster, and performance of the current database query is managed based on the query-execution characteristic.