When deleting large numbers (5000+) of builds from a config, QB will consume very large amounts of memory to the point that it can end up stuck with all actions failing due to exhausted Java heap -- we've seen this also peg CPU usage. When this occurs, the system becomes unresponsive, all processing appears to stop, and no more entries are written to the console or quickbuild logs.

This issue can be manually triggered by selecting all "Delete all builds" option on a config with a very large number of builds. It also happens during System Maintenance if a configuration's "Build Cleanup Strategy" has changed to cause large numbers of builds to be deleted.