Abstract: A computing resource monitoring service detects an issue with processing of metrics data. The metrics data is stored in observation journals within an observation journal logical data container. A computing resource service provider may configure a map reduce processor to select a prior version of an index file, the index file comprising a mapping of the metrics data stored within a metric store and a manifest comprising a listing of all processed observation journals. The map reduce processor may identify newly unprocessed observation journals and process these journals in order to generate new data objects and a new version of an index. Subsequently, an index pointer may be modified such that obsolete versions of the index are removed and the map reduce processor refers to a different version of the index file in order to support future roll back of metrics data.