Sean Owen commented on SPARK-17971:

Oops I copied the wrong link.  I mean :


A UNIX timestamp defines the same point in time and does not depend on a 
timezone to interpret it. I think we are clear on that and it isn't the point. 
You just need the methods that don't use system tz.

> Unix timestamp handling in Spark SQL not allowing calculations on UTC times
> ---------------------------------------------------------------------------
>                 Key: SPARK-17971
>                 URL: https://issues.apache.org/jira/browse/SPARK-17971
>             Project: Spark
>          Issue Type: Bug
>          Components: Spark Core, SQL
>    Affects Versions: 1.6.2
>         Environment: MacOS X JDK 7
>            Reporter: Gabriele Del Prete
> In our Spark data pipeline we store timed events using a bigint column called 
> 'timestamp', the values contained being Unix timestamp time points.
> Our datacenter servers Java VMs are all set up to start with timezone set to 
> UTC, while developer's computers are all in the US Eastern timezone. 
> Given how Spark SQL datetime functions work, it's impossible to do 
> calculations (eg. extract and compare hours, year-month-date triplets) using 
> UTC values:
> - from_unixtime takes a bigint unix timestamp and forces it to the computer's 
> local timezone;
> - casting the bigint column to timestamp does the same (it converts it to the 
> local timezone)
> - from_utc_timestamp works in the same way, the only difference being that it 
> gets a string as input instead of a bigint.
> The result of all of this is that it's impossible to extract individual 
> fields of a UTC timestamp, since all timestamp always get converted to the 
> local timezone.

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