Comment 1 for bug 1676519

seems related to new lz4. prior to 0.9.0, it allowed compression/decompression of empty value to be valid. for example, lz4.loads(lz4.dumps(b'')) works in 0.8.2 but in 0.9.0, it will throw an error instead.

in theory, it actually is an error that unaggregated object is empty... i imagine it's because metricd is killed in process of initial aggregation and saving of unaggregated.