The full filename will be: `yyyyMMdd_$SHARDS_$NANOTIME.json.gz`

where $SHARDS will be something like '0,1,2,3,4,5,6,7'

and $NANOTIME is time in nanoseconds

i.e: '20140207_104,105,106,107,108,109,110,111_1391549480000000000.json.gz'