1. A method for operating a configuration management database (CMDB), the method comprising: for a configuration item in a configuration management database (CMDB), responsive to updating the configuration item, determining, by one or more processors, a last update time associated with the updated configuration item; receiving, by one or more processors, an indication to delete a configuration item; responsive to receiving the indication to delete the configuration item, determining, by one or more processors, whether an age of the configuration item is greater than a threshold, wherein the threshold comprises a difference between a current time and the last update time; responsive to determining that the age of the configuration item is greater than the threshold, assigning, by one or more processors, the configuration item a deletion-candidate label; identifying, by one or more processors, a set of configuration items associated with a set of nodes of a directed graph, wherein the set of nodes of the directed graph are assigned the deletion-candidate label; and deleting, by one or more processors, the set of identified configuration items assigned the deletion-candidate label.