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https://issues.apache.org/jira/browse/SQOOP-3288?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16371674#comment-16371674
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Daniel Voros commented on SQOOP-3288:
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Great, thank you [~maugli]!
> 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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