The described technology is generally directed towards causing the generation of a content selection graph (or set of graphs) upon receipt of a notification that a new graph or replacement graph is needed with respect to a starting timepoint. For a new graph, a timepoint for that new graph indicates the need for the new graph at a given starting time. For a replacement graph, a notification (subscribed from a monitoring service) can indicate that an existing graph has changed; a replacement graph is generated with a graph identifier of the replacement graph, which then replaces the graph identifier of the existing graph in the mappings of valid graphs to start times. A Redis cache can be used to maintain the various graph sets, including the active graph sets and graph sets that will become active at a future time.