1. A method for executing database commands, the method comprising: receiving a plurality of requests from a plurality of database clients, the plurality of requests requesting execution of a plurality of database commands; executing the plurality of database commands according to plans identified for the plurality of database commands; while executing the plurality of database commands according to the plans, collecting first information, wherein the first information is related to execution of the plurality of database commands according to the plans; for each database command in the plurality of database commands, determining whether the database command matches one or more pre-defined criteria; when it is determined that a database command, of the plurality of database commands, matches the one or more pre-defined criteria, persistently recording, in historical information for the database command, information collected in relationship with execution of the database command; when it is determined that a database command, of the plurality of database commands, does not match the one or more pre-defined criteria, not persistently recording, in historical information for the database command, the information collected in relationship with execution of the database command; receiving a particular request to execute a previously executed database command of the plurality of database commands; in response to the particular request: determining that information collected in relationship with one or more previous executions of the previously executed database command has been persistently recorded in historical information for the previously executed database command; and executing the previously executed database command using, at least in part, the information collected in relationship with the execution of the previously executed database command; wherein the steps are performed by one or more computing devices.