1. A system of selective constant complexity dismissal in task scheduling of a plurality of tasks, each described by one of a plurality of task records, in a computing environment, comprising: at least one processor device, operable in the computing environment, wherein the processor device is adapted for performing: placing the plurality of task records in a task queue, implementing a strictly increasing function to generate a plurality of unique creation stamps, each of the plurality of unique creation stamps increasing over time pursuant to the strictly increasing function, labeling a new task to be placed with the plurality of tasks with a new unique creation stamp of the plurality of unique creation stamps, implementing a dismissal action by at least one of a list of dismissal rules against at least one of the plurality of tasks, wherein the one of the list of dismissal rules holds a minimal valid creation (MVC) stamp and the dismissal rules refer to criteria matching specific attributes of a task record, the criteria being unrelated to the unique creation stamps, the MVC stamp updated when the dismissal action for the one of the list of dismissal rules is executed, dequeueing a task from the plurality of tasks for execution, identifying a match between one of the list of dismissal rules referring to criteria unrelated to the unique creation stamps and a specific attribute of the task dequeued for execution and determining whether the task dequeued for execution has a unique creation stamp lower than the MVS stamp, dismissing the task dequeued for execution to thereby prevent execution thereof, if the specific attribute of the task dequeued for execution matches the one of the list of dismissal rules and has a unique creation stamp lower than the MVC stamp, executing the task dequeued for execution, if the specific attribute of the task dequeued for execution does not match the list of dismissal rules or if the task dequeued for execution has a unique creation stamp that is not lower than the MVC stamp, and selecting a next task to be dequeued from the plurality of tasks for execution and iterating the steps of identifying and dismissing.