[
https://issues.apache.org/jira/browse/HIVE-12192?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16221507#comment-16221507
]
Jesus Camacho Rodriguez edited comment on HIVE-12192 at 10/27/17 12:28 AM:
---------------------------------------------------------------------------
Very much wip but I had been working on this so I attach a draft to see what
ptest gives. The idea would be to store the timestamp in ORC as UTC too, but a
couple of constructors for the reader/writer of timestamp values need to be
extended so we can specify the timezone ourselves instead of taking the system
timezone automatically.
was (Author: jcamachorodriguez):
Very much wip but I had been working on this so I attach a draft to see what
ptest gives. The idea would be to store the timestamp in ORC as UTC too, but a
couple of constructors for the reader/writer of timestamp values need to be
extended so we can specify the timezone ourselves instead of taking the system
timezone.
> Hive should carry out timestamp computations in UTC
> ---------------------------------------------------
>
> Key: HIVE-12192
> URL: https://issues.apache.org/jira/browse/HIVE-12192
> Project: Hive
> Issue Type: Sub-task
> Components: Hive
> Reporter: Ryan Blue
> Assignee: Jesus Camacho Rodriguez
> Labels: timestamp
> Attachments: HIVE-12192.patch
>
>
> Hive currently uses the "local" time of a java.sql.Timestamp to represent the
> SQL data type TIMESTAMP WITHOUT TIME ZONE. The purpose is to be able to use
> {{Timestamp#getYear()}} and similar methods to implement SQL functions like
> {{year}}.
> When the SQL session's time zone is a DST zone, such as America/Los_Angeles
> that alternates between PST and PDT, there are times that cannot be
> represented because the effective zone skips them.
> {code}
> hive> select TIMESTAMP '2015-03-08 02:10:00.101';
> 2015-03-08 03:10:00.101
> {code}
> Using UTC instead of the SQL session time zone as the underlying zone for a
> java.sql.Timestamp avoids this bug, while still returning correct values for
> {{getYear}} etc. Using UTC as the convenience representation (timestamp
> without time zone has no real zone) would make timestamp calculations more
> consistent and avoid similar problems in the future.
> Notably, this would break the {{unix_timestamp}} UDF that specifies the
> result is with respect to ["the default timezone and default
> locale"|https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF#LanguageManualUDF-DateFunctions].
> That function would need to be updated to use the
> {{System.getProperty("user.timezone")}} zone.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
