Github user jackylk commented on the issue:
https://github.com/apache/carbondata/pull/1316
I think it is not good to have both `CARBON_TIMESTAMP_MILLIS` and
`CARBON_TIMESTAMP_DEFAULT_FORMAT` in CarbonCommonConstants. Why not using
`CARBON_TIMESTAMP_DEFAULT_FORMAT` only and delete `CARBON_TIMESTAMP_MILLIS`?---
