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From "Jason Dere (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-14412) Add a timezone-aware timestamp
Date Thu, 29 Sep 2016 17:45:21 GMT

    [ https://issues.apache.org/jira/browse/HIVE-14412?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15533471#comment-15533471
] 

Jason Dere commented on HIVE-14412:
-----------------------------------

bq. I thought about this. One difficulty is we need to serialize TimestampTZ into BytesWritable
in BinarySortableSerDe. The timezone needs to be serialized into the BytesWritable. I'm not
sure how to keep it from being used for comparison.

I'm not sure what to do here - I feel like proper comparison is an important detail, and that
users might be alarmed if the data they are collecting in various time zones are not capable
of being compared to each other. I wonder if it would worth creating a new BinarySortableSerDe
which allows the value to specify how many bytes of the value need to be compared. Something
like that might allow the TimestampTZ to specify that only the UTC time portion be used for
comparison.

If anything, I think the most important detail for a new Timestamp type in Hive would be to
make sure that it actually captures the "seconds from UTC" value and that all of the various
SerDes/UDFs/conversions actually pay attention to this detail. The formatting/Timezone could
even be done as an operation on the UTC time (formatting UDF, session-level timezone, or just
use local timezone).


> Add a timezone-aware timestamp
> ------------------------------
>
>                 Key: HIVE-14412
>                 URL: https://issues.apache.org/jira/browse/HIVE-14412
>             Project: Hive
>          Issue Type: Sub-task
>          Components: Hive
>            Reporter: Rui Li
>            Assignee: Rui Li
>         Attachments: HIVE-14412.1.patch, HIVE-14412.2.patch, HIVE-14412.3.patch, HIVE-14412.4.patch,
HIVE-14412.5.patch, HIVE-14412.6.patch, HIVE-14412.7.patch, HIVE-14412.8.patch
>
>
> Java's Timestamp stores the time elapsed since the epoch. While it's by itself unambiguous,
ambiguity comes when we parse a string into timestamp, or convert a timestamp to string, causing
problems like HIVE-14305.
> To solve the issue, I think we should make timestamp aware of timezone.



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