[2875]two different threads overwriting the same carbondatafile

[shardul-cr7]

Problem : Two different threads are overwriting the same carbondata file during creation of external table.

Solution: Chances of two threads concurrently loading same carbondatafile is reduced by changing the timestamp attached in .carbondata file from millisecond to nanosecond.So chances of collision of different threads having the same file name is reduced.

Be sure to do all of the following checklist to help us incorporate
your contribution quickly and easily:

• Any interfaces changed?

• Any backward compatibility impacted?

• Document update required?

• Testing done
  Done Manually

• For large changes, please consider breaking it into sub-tasks under an umbrella JIRA.

[CarbonDataQA]

Can one of the admins verify this patch?

[CarbonDataQA]

Can one of the admins verify this patch?