Impala

Starting with version 4.2.0, Apache Impala provides full support for querying data stored in Apache Ozone. To utilize this functionality, ensure that your Ozone version is 1.4.0 or later.

Supported Access Protocols

Impala supports the following protocols for accessing Ozone data:

• ofs
• s3a

Note: The o3fs protocol is NOT supported by Impala.

Supported Replication Types

Impala is compatible with Ozone buckets configured with either:

• RATIS (Replication)
• Erasure Coding

Querying Ozone Data with Impala

Impala provides two approaches to interact with Ozone:

• Managed Tables
• External Tables

Managed Tables

If the Hive Warehouse Directory is located in Ozone, you can execute Impala queries without any changes, treating the Ozone file system like HDFS. For example:

CREATE DATABASE d1;

CREATE TABLE t1 (x INT, s STRING);

The data will be stored under the Hive Warehouse Directory path in Ozone.

Specifying a Custom Ozone Path

You can create managed databases, tables, or partitions at a specific Ozone path using the LOCATION clause. Example:

CREATE DATABASE d1 LOCATION 'ofs://ozone1/vol1/bucket1/d1.db';

CREATE TABLE t1 LOCATION 'ofs://ozone1/vol1/bucket1/table1';

External Tables

You can create an external table in Impala to query Ozone data. For example:

CREATE EXTERNAL TABLE external_table (
  id INT,
  name STRING
)
LOCATION 'ofs://ozone1/vol1/bucket1/table1';

• With external tables, the data is expected to be created and managed by another tool.
• Impala queries the data as-is.
• The metadata is stored under the external warehouse directory.
• Note: Dropping an external table in Impala does not delete the associated data.

Using the S3A Protocol

In addition to ofs, Impala can access Ozone via the S3 Gateway using the S3A file system. For more details, refer to

• The S3 Protocol
• The Hadoop S3A documentation.

For additional information, consult the Apache Impala User Documentation Using Impala with Apache Ozone Storage.