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https://issues.apache.org/jira/browse/HIVE-8839?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14227127#comment-14227127
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Szehon Ho commented on HIVE-8839:
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I did some doc cleanup in that section:
[https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-AlterColumn|https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-AlterColumn]
hopefully it makes sense.
Yea to answer [~leftylev]'s question, I took a look and there is already an
ALTER TABLE enable {mode} CASCADE which is not documented. Apparently, you can
enable {mode} of "NO_DROP", "OFFLINE", and "READONLY" as of HIVE-1413. If any
mode is set, we cant drop the table. If OFFLINE is there then we cant query it
either. And CASCADE will extend NO_DROP protection to the children as of
HIVE-2605. We should probably document this?
Chaoyu, yea it might make sense to create a followup JIRA as you suggested,
though I dont think any of these modes seem to be a great fit for protecting
the partition from this change.
> Support "alter table .. add/replace columns cascade"
> ----------------------------------------------------
>
> Key: HIVE-8839
> URL: https://issues.apache.org/jira/browse/HIVE-8839
> Project: Hive
> Issue Type: Improvement
> Components: SQL
> Environment:
> Reporter: Chaoyu Tang
> Assignee: Chaoyu Tang
> Labels: TODOC15
> Fix For: 0.15.0
>
> Attachments: HIVE-8839.1.patch, HIVE-8839.2.patch, HIVE-8839.2.patch,
> HIVE-8839.patch
>
>
> We often run into some issues like HIVE-6131which is due to inconsistent
> column descriptors between table and partitions after alter table.
> HIVE-8441/HIVE-7971 provided the flexibility to alter table at partition
> level. But most cases we have need change the table and partitions at same
> time. In addition, "alter table" is usually required prior to "alter table
> partition .." since querying table partition data is also through table.
> Instead of do that in two steps, here we provide a convenient ddl like "alter
> table ... cascade" to cascade table changes to partitions as well. The
> changes are only limited and applicable to add/replace columns and change
> column name, datatype, position and comment.
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