Jens Klöker created HIVE-21129:
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Summary: from_utc_timestamp date function does not work like it
should
Key: HIVE-21129
URL: https://issues.apache.org/jira/browse/HIVE-21129
Project: Hive
Issue Type: Bug
Affects Versions: 1.2.1
Reporter: Jens Klöker
# I have a datetime value which is meant to be in UTC time. By using
from_utc_timestamp I want to get the correct unix timestamp out of this date. I
would think, that I don't have to define a timezone, and if I have to define a
timezone it should be UTC. However to get a correct conversion to unix
timestamps I have to define 'CET' as timezone string. This is kind of confusing
to me. Additional information: 'CET' is the timezone of the servers, on which
hive is running. Maybe in other timezones users currently have to define their
timezone, to get a correct unix timestamp. But in my opinion, a definition of a
timezone should not be necessary to convert from UTC datetime to UTC unix
timestamp. However I fixed it by defining CET. This is the reason, why I'm
afraid of a future correction. My timezone string will then probably get
incorrect resulting in incorrect unix timestamps in my implementation.
# After implementing the CET-workaround described in the first point I get
correct results for the unix timestamp. However on 28^th^ of Oct. 2018 some
timestamps are not calculated correctly (1 hour difference). On this date there
has been a "daylight-saving-time" event in 'CET' timezone. The clock has been
set from 03:00:00 to 02:00:00. This is a strong hint, that additional to the
issue described first, there is also something wrong when it comes to timezone
conversions near such events. I observed this behavior with data between
00:00:00 and 01:00:00. I don't know if this behavior can be observed between
02:00:00 and 24:00:00.
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