1. A method, implemented at least partly by a device, the method comprising: configuring the database system to operate at a limited capacity below its full capacity for execution of database queries of a database, wherein the database system includes one or more processors operable to process data stored in the database in a database environment in order to process the database queries; learning about optimization of execution of one or more selected database queries that do not meet at least one performance criteria associated with a target performance for processing the selected database queries with the limited capacity in the database environment, by using the excess capacity of the database system configured to operate with the limited capacity for the execution of database queries of the database; allowing at least one portion of the excess capacity available to the database system to be used to perform one or more learning activities associated with learning about optimization of execution of one or more selected database queries in the database environment that do not meet at least one performance criteria; and not allowing the at least one portion of the excess capacity available to the database system to be used to perform other activities not associated with the learning about optimization of execution of the database queries in the database environment.