Technologies are described for facilitating transaction processing within a database environment that includes one or more processing units and a memory. A request for a database operation, such as a query, is received from a client. Execution statistics associated with the request are retrieved. At least some of the execution statistics are compared with one or more threshold values. Based on results of the comparing, the request is carried out with a first execution component or delegated to a second execution component. The request is executed and execution results are sent to the client.