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https://issues.apache.org/jira/browse/HIVE-20095?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16541201#comment-16541201
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Daniel Dai edited comment on HIVE-20095 at 7/12/18 6:26 AM:
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Haven't read through the patch but the motivation of the change in HIVE-19161
is to rely on table schema rather than ResultSet to determine the object type
of the results. Same sql expression could be interpreted as different datatype
in ResultSet for different databases, thus the result for the same expression
could be different datatype for different database. Rely on table schema is
more reliable. I don't remember a concrete example out of my head but there
must be one inside hive-schema-3.1.0.hive.sql. I can find it if needed. I am
not sure how this breaks PPD, is that "hiveQueryExecution" part in JdbcSerDe?
If we can fix it and keep relying on table schema for result type, that should
be fine for me.
was (Author: daijy):
Haven't read through the patch but the motivation of the change in HIVE-19161
is to rely on table schema rather than ResultSet to determine the object type
of the results. Same sql expression could be interpreted as different datatype
in ResultSet for different databases, thus the result for the same expression
could be different datatype for different database. Rely on table schema is
more reliable. I don't remember a concrete example out of my head but there
must be on inside hive-schema-3.1.0.hive.sql. I can find it if needed. I am not
sure how this breaks PPD, is that "hiveQueryExecution" part in JdbcSerDe? If we
can fix it and keep rely on table schema for result type, that should be fine
for me.
> Fix jdbc external table feature
> -------------------------------
>
> Key: HIVE-20095
> URL: https://issues.apache.org/jira/browse/HIVE-20095
> Project: Hive
> Issue Type: Bug
> Reporter: Jonathan Doron
> Assignee: Jonathan Doron
> Priority: Major
> Attachments: HIVE-20095.1.patch, HIVE-20095.2.patch,
> HIVE-20095.3.patch
>
>
> It seems like the committed code for HIVE-19161
> (7584b3276bebf64aa006eaa162c0a6264d8fcb56) reverted some of HIVE-18423
> updates, and therefore some of the external table queries are not working
> correctly.
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