Creating partitions dynamically

You can configure Hive to create partitions dynamically and then run a query that creates the related directories on the file system or object store. Hive then separates the data into the directories.

This example assumes you have the following CSV file named employees.csv to use as the data source:

1,jane doe,engineer,service
2,john smith,sales rep,sales
3,naoko murai,service rep,service
4,somporn thong,ceo,sales
5,xi singh,cfo,finance

Upload the CSV file to a file system.

In the Hive shell, create an unpartitioned table that holds all the data.

CREATE EXTERNAL TABLE employees (eid int, name string, position string, dept string)
  ROW FORMAT DELIMITED
  FIELDS TERMINATED BY ','
  STORED AS TEXTFILE
  LOCATION '<object store or file system path>';

For example, specify an Ozone location 'ofs://ozone1/vol1/bucket1/employees'.

Check that the data loaded into the employees table.

SELECT * FROM employees;

The output, formatted to fit this publication, appears:


+------+---------------+-------------+-------+---------+
| eid  |    name       | position    | dept  |         |
+------+---------------+-------------+-------+---------|
| 1    | jane doe      | engineer    | service         |
| 2    | john smith    | sales rep   | sales           |
| 3    | naoko murai   | service rep | service         |
| 4    | somporn thong | ceo         | sales           |
| 5    | xi singh      | cfo         | finance         |
+------+---------------+-------------+-----------------+

Create a partition table.

CREATE EXTERNAL TABLE EMP_PART (eid int, name string, position string) 
  PARTITIONED BY (dept string);

Accept the default dynamic partition mode (nonstrict) to create partitioned directories of data dynamically when data is inserted, or if you changed the default, reset the mode as follows:
```
SET hive.exec.dynamic.partition.mode=nonstrict;
```
Insert data from the unpartitioned table (all the data) into the partitioned table , dynamically creating the partitions.
```
INSERT INTO TABLE EMP_PART PARTITION (DEPT)
  SELECT eid,name,position,dept FROM employees;
```
Partitions are created dynamically.

Check that the partitions were created.

SHOW PARTITIONS emp_part;

+----------------+
|   partition    |
+----------------+
| dept=finance   |
| dept=sales     |
| dept=service   |
+----------------+