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https://issues.apache.org/jira/browse/IMPALA-11906?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17698537#comment-17698537
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ASF subversion and git services commented on IMPALA-11906:
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Commit 27e238c8cf31e5c28ad0fe63a1aeabf2a6e05414 in impala's branch 
refs/heads/dependabot/pip/infra/python/deps/wheel-0.38.1 from Shajini Thayasingh
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=27e238c8c ]

IMPALA-11906: [DOCS] Document the support for non-unique primary key

Incorporated the comments received.
Added a new sub-section.
Change-Id: I7b5a452f2199d097077150c012497aa4a3ecf7d9
Reviewed-on: http://gerrit.cloudera.org:8080/19587
Tested-by: Impala Public Jenkins <[email protected]>
Reviewed-by: Abhishek Chennaka <[email protected]>
Reviewed-by: Wenzhe Zhou <[email protected]>


> Impala Doc: Support non unique primary key for Kudu table
> ---------------------------------------------------------
>
>                 Key: IMPALA-11906
>                 URL: https://issues.apache.org/jira/browse/IMPALA-11906
>             Project: IMPALA
>          Issue Type: Documentation
>          Components: Docs
>    Affects Versions: Impala 4.3.0
>            Reporter: Wenzhe Zhou
>            Assignee: shajini thayasingh
>            Priority: Major
>              Labels: documentation
>             Fix For: Impala 4.3.0
>
>
> IMPALA-11809 Added support non unique primary key for Kudu table. We should 
> document the syntax for non unique primary key.
> - We added syntactic support for creating Kudu table with non unique primary 
> key.
>   For example: 
>     CREATE TABLE tbl (id INT NON UNIQUE PRIMARY KEY, name STRING)
>     PARTITION BY HASH (id) PARTITIONS 3
>     STORED as KUDU;
>   More samples could be found in the commit messages of 
> https://issues.apache.org/jira/browse/IMPALA-11809
> - Kudu engine appends a system generated auto-incrementing column to the non 
> unique primary key columns to guarantee the uniqueness on primary key. This 
> auto-incrementing column is named as 'auto_incrementing_id' with bigint type. 
> The assignment to it during insertion is automatic.
> 'auto_incrementing_id' column cannot be added, removed or renamed with ALTER 
> TABLE statements.
> - When creating a Kudu table, specifying PRIMARY KEY is optional now. If 
> there is no primary key attribute specified, the partition key columns could 
> be promoted as non unique primary key if those columns are the beginning 
> columns of the table.
> In following sample, 'a' and 'b' will be promoted as non unique primary key, 
> 'auto_incrementing_id' column will be added by Kudu engine.  'a', 'b' and 
> 'auto_incrementing_id' form the effective unique composite primary key.
>     CREATE TABLE tbl (a INT, b STRING, c FLOAT)
>      PARTITION BY HASH (a, b) PARTITIONS 3
>      STORED as KUDU;
> - New column "key_unique" is added to the output of 'describe' table command 
> for Kudu table, which shows if the primary key is unique.
> -  SELECT statement does not show the system generated auto-incrementing 
> column unless the column is explicitly specified in the select list.
> - UPSERT operation is not supported for Kudu tables with non unique primary 
> key.



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