Abstract: A method of controlling the allocation of resources in a parallel processor computer. A critical path for executing a task such as evaluating a database query is determined. The minimum time to execute the task assuming infinite resources such as processors and memory buffers is calculated. Resources are scheduled against subtasks so as to execute the task in the calculated minimum time. The number of resources would be required to meet the schedule is determined and if the computer has that many resources the schedule is carried out. Otherwise a revised execution time is calculated, preferably by using as a scaling factor the ratio between the number of required resources and the number of available resources. Then the schedule is adjusted so that the task can be executed in the revised time and the number of resources that would be required to meet the adjusted schedule is determined. If the computer has that many resources the schedule is carried out, otherwise the process is repeated.