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https://issues.apache.org/jira/browse/HIVE-957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12783996#action_12783996
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Zheng Shao commented on HIVE-957:
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A. Replace the column separator for all partitions (because they created the
table with wrong separator)
Users need to change partition metadata.
B. Append additional columns
In the long term, users don't want to change partition metadata for this - We
should fix Hive execution time to support missing columns (returning NULL) (
S1: Currently Hive execution time will output an error if the column in the
expression is missing from the row object)
C. Rename existing columns
Users need to change partition metadata.
This patch will solve the problem caused by the following 3 items:
1. "S1" above
2. Hive execution time using partition metadata
3. User append additional columns by changing table metadata only
> Partiition Metadata and Table Metadata
> --------------------------------------
>
> Key: HIVE-957
> URL: https://issues.apache.org/jira/browse/HIVE-957
> Project: Hadoop Hive
> Issue Type: Bug
> Reporter: He Yongqiang
> Attachments: hive-957-2009-11-30.patch
>
>
> Right now, we choose to use partition lever metadata. All metadata (column
> names, column types, fileformat, serde class, serde properties) right now are
> from partition level metadata. But hive does not support a method now to
> alter all existing partitions' metadata, so users mostly choose to alter
> table metadata, and think hive will use the new table level metadata.
> One approach is that we may need to provide a way to let user alter all
> partitions' metadata with one simple command. Right now a short term solution
> is to only get fileformat, serde class metadata from paritition level
> metadata, and use all other metadata from table.
> any comments?
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