I should have left a comment here. There's a distinction between the data server reporting no data at a timestamp and the data server not having any response for a timestamp. The graph you showed me yesterday that had all the lines dashed like it was in historical mode was actually just Ganglia and StatMonster timestamps being spaced inconsistently, leading to extra nulls in the data which caused the graphs to have artificial spaces in them. `NO_DATA_FOR_TIMESTAMP` is a sentinel which indicates that a timestamp had no data for the data source in that position; if `processData` comes across it, it shouldn't store any data for that stat at that timestamp.