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From "Zheng Shao (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-957) Partiition Metadata and Table Metadata
Date Tue, 01 Dec 2009 01:41:21 GMT

    [ https://issues.apache.org/jira/browse/HIVE-957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12783996#action_12783996
] 

Zheng Shao commented on HIVE-957:
---------------------------------

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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