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https://issues.apache.org/jira/browse/SQOOP-3288?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16371502#comment-16371502
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Daniel Voros commented on SQOOP-3288:
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[~maugli] it's the other way around. We were getting the OS time before, that's
what this patch is supposed to fix. (Also, please note, that we were not
relying on the time of the OS running the sqoop job, but the OS running Oracle.)
> Incremental import's upper bound ignores session time zone in Oracle
> --------------------------------------------------------------------
>
> Key: SQOOP-3288
> URL: https://issues.apache.org/jira/browse/SQOOP-3288
> Project: Sqoop
> Issue Type: Bug
> Components: connectors/oracle
> Affects Versions: 1.4.7
> Reporter: Daniel Voros
> Assignee: Daniel Voros
> Priority: Major
> Fix For: 1.5.0
>
> Attachments: SQOOP-3288.1.patch
>
>
> At the moment we're using [{{SELECT SYSDATE FROM
> dual}}|https://github.com/apache/sqoop/blob/3153c3610da7e5db388bfb14f3681d308e9e89c6/src/java/org/apache/sqoop/manager/OracleManager.java#L652]
> when getting current time from Oracle.
> SYSDATE returns the underlying operating system's current time, while
> CURRENT_TIMESTAMP uses the session time zone. This could lead to problems
> during incremental imports *when Oracle's time zone is different from the OS*.
> Consider the following scenario when Oracle is configured to {{+0:00}}, while
> the OS is {{+5:00}}:
> ||Oracle time||OS time||Event||
> |2:00|7:00|{{sqoop import --last-value 1:00 ...}} => imports {{[1:00, 7:00)}}|
> |2:30|7:30|{{update ... set last_updated = current_timestamp ...}} => set to
> {{2:30}} *Won't be imported!*|
> |3:00|8:00|{{sqoop import --last-value 7:00 ...}} => imports {{[7:00, 8:00)}}|
> This way records updated within 5 hours after the last sqoop import won't get
> imported.
> Please note, that the example above assumes, that the user/administrator
> who's updating the Oracle table will use the current session time of Oracle
> when setting the "last updated" column of the table.
> I think the solution is to use CURRENT_TIMESTAMP instead of SYSDATE. Other
> connection managers, like MySQL or PostgreSQL are using that as well.
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