Abstract: A clustered computing environment with application staging, including a plurality of application instances running on at least one computer and operating in a clustered computing environment, and a stage manager operative to manage the transition of any of the application instances between a front stage assignment and a back stage assignment, where any of the application instances that are assigned as front stage application instances service requests, and where any of the application instances that are assigned as back stage application instances ceases to service requests and performs at least one maintenance task.

Abstract: A method for incremental compaction, including selecting a first section from a plurality of sections in a memory, and identifying references to elements in the first section. While identifying, selecting a sub-area of the first section and continuing the identifying while identifying only those references to elements in the sub-area. The method further includes holding in a data structure the identified references to elements in the first section, and if the data structure overflows, deleting from the data structure the reference elements not in the sub-area. The identifying is continued while holding in the data structure only those references to elements in the sub-area. Selecting, identifying and continuing may be performed by a plurality of threads performing the steps in parallel.