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https://issues.apache.org/jira/browse/IMPALA-11906?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17686128#comment-17686128
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Wenzhe Zhou commented on IMPALA-11906:
--------------------------------------
Samples with non unique primary keys:
{code:java}
[localhost:21050] default> CREATE TABLE kudu_tbl1 (id INT NON UNIQUE PRIMARY
KEY, name STRING) PARTITION BY HASH (id) PARTITIONS 3 STORED as KUDU;
Query: CREATE TABLE kudu_tbl1 (id INT NON UNIQUE PRIMARY KEY, name STRING)
PARTITION BY HASH (id) PARTITIONS 3 STORED as KUDU
+-------------------------+
| summary |
+-------------------------+
| Table has been created. |
+-------------------------+
Fetched 1 row(s) in 4.79s
[localhost:21050] default> desc kudu_tbl1;
Query: describe kudu_tbl1
+----------------------+--------+---------+-------------+------------+----------+---------------+---------------+---------------------+------------+
| name | type | comment | primary_key | key_unique | nullable
| default_value | encoding | compression | block_size |
+----------------------+--------+---------+-------------+------------+----------+---------------+---------------+---------------------+------------+
| id | int | | true | false | false
| | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| auto_incrementing_id | bigint | | true | false | false
| | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
| name | string | | false | | true
| | AUTO_ENCODING | DEFAULT_COMPRESSION | 0 |
+----------------------+--------+---------+-------------+------------+----------+---------------+---------------+---------------------+------------+
Fetched 3 row(s) in 4.72s
[localhost:21050] default>
{code}
> 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
>
> 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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