[jira] [Commented] (ORC-10) Fix timestamp moving between timezones (HIVE-8746 in C++)

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ORC-10?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16404361#comment-16404361 ] 

ASF GitHub Bot commented on ORC-10:
-----------------------------------

Github user wgtmac commented on a diff in the pull request:

    https://github.com/apache/orc/pull/18#discussion_r175328447
  
    --- Diff: c++/src/ColumnReader.cc ---
    @@ -327,7 +329,9 @@ namespace orc {
                 nanoBuffer[i] *= 10;
               }
             }
    -        secsBuffer[i] += epochOffset;
    +        int64_t writerTime = secsBuffer[i] + epochOffset;
    +        secsBuffer[i] = writerTime +
    --- End diff --
    
    @omalley I think here introduces an inconsistency between reader and writer. The secsBuffer[i] in the TimestampVectorBatch of reader side will not get same value on the java writer/reader side.


> Fix timestamp moving between timezones (HIVE-8746 in C++)
> ---------------------------------------------------------
>
>                 Key: ORC-10
>                 URL: https://issues.apache.org/jira/browse/ORC-10
>             Project: ORC
>          Issue Type: Bug
>          Components: C++, encoding
>            Reporter: Owen O'Malley
>            Assignee: Owen O'Malley
>            Priority: Major
>             Fix For: 1.1.0
>
>
> ORC stores the difference from an epoch in the local timezone. That makes ORC mostly resilient when moving between timezones, but fails when moving between timezones with different daylight savings rules.
> ORC currently stores the timezone information in the stripe footer, so that the reader can understand the times correctly.



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