How to perform data partitioning in Impala?

1 year ago

Jackson Davis

1 minute

In Impala, data partitioning can be achieved using the PARTITION BY clause. When creating a table, one or more columns can be specified as partition keys, for example:

CREATE TABLE mytable (
    id INT,
    name STRING
)
PARTITIONED BY (date STRING)

In the example above, the table “mytable” uses the date column as the partition key. When inserting data into the table, you can specify the partition to which the data belongs, for example:

INSERT INTO mytable PARTITION (date='2022-01-01') VALUES (1, 'Alice');

You can use the command “show partitions” to view existing partitions.

SHOW PARTITIONS mytable;

You can also use the ALTER TABLE command to add new partitions to an existing table.

ALTER TABLE mytable ADD PARTITION (date='2022-01-02');

Partitioning data can enhance query performance by reducing the scope of data scans and improving query efficiency.