Configuring Impala to Work with JDBC
Impala supports JDBC integration. The JDBC driver allows you to access Impala from a Java program that you write, or a Business Intelligence or similar tool that uses JDBC to communicate with various database products. Setting up a JDBC connection to Impala involves the following steps:
- Specifying an available communication port. See Configuring the JDBC Port.
- Installing the JDBC driver on every system that runs the JDBC-enabled application. See Enabling Impala JDBC Support on Client Systems.
- Specifying a connection string for the JDBC application to access one of the servers running the impalad daemon, with the appropriate security settings. See Establishing JDBC Connections.
Configuring the JDBC Port
The default port used by JDBC 2.0 (as well as ODBC 2.x) is 21050. Impala server accepts JDBC connections through this same port 21050 by default. Make sure this port is available for communication with other hosts on your network, for example, that it is not blocked by firewall software. If your JDBC client software connects to a different port, specify that alternative port number with the --hs2_port option when starting impalad. See Starting Impala for details.
Enabling Impala JDBC Support on Client Systems
The Impala JDBC integration is made possible by a client-side JDBC driver, made up of some Java JAR files. The same driver is used by Impala and Hive. To get the JAR files, install the Hive JDBC driver on one machine by following the instructions for CDH 4 or CDH 5. Download the JAR files to each client machine that will use JDBC with Impala:
commons-logging-X.X.X.jar hadoop-common.jar hive-common-X.XX.X-cdhX.X.X.jar hive-jdbc-X.XX.X-cdhX.X.X.jar hive-metastore-X.XX.X-cdhX.X.X.jar hive-service-X.XX.X-cdhX.X.X.jar libfb303-X.X.X.jar libthrift-X.X.X.jar log4j-X.X.XX.jar slf4j-api-X.X.X.jar slf4j-logXjXX-X.X.X.jar
To enable JDBC support for Impala on the system where you run the JDBC application:
Download the JAR files listed above to each client machine.
:For Maven users, see this sample github page for an example of the dependencies you could add to a pom file instead of downloading the individual JARs.
Store the JAR files in a location of your choosing, ideally a directory already referenced in your CLASSPATH setting.
- On Linux, you might use a location such as /opt/jars/.
- On Windows, you might use a subdirectory underneath C:\Program Files.
To successfully load the Impala JDBC driver, client programs must be able to locate the associated JAR files.
This often means setting the CLASSPATH for the client process to include the JARs. Consult the
documentation for your JDBC client for more details on how to install new JDBC drivers, but some examples of
how to set CLASSPATH variables include:
On Linux, if you extracted the JARs to /opt/jars/, you
might issue the following command to prepend the JAR files path to an existing classpath:
On Windows, use the System Properties control panel item to modify the
Environment Variables for your system. Modify the environment variables
to include the path to which you extracted the files.
:If the existing CLASSPATH on your client machine refers to some older version of the Hive JARs, ensure that the new JARs are the first ones listed. Either put the new JAR files earlier in the listings, or delete the other references to Hive JAR files.
- On Linux, if you extracted the JARs to /opt/jars/, you might issue the following command to prepend the JAR files path to an existing classpath:
Establishing JDBC Connections
The JDBC driver class is org.apache.hive.jdbc.HiveDriver. Once you have configured Impala to work with JDBC, you can establish connections between the two. To do so for a cluster that does not use Kerberos authentication, use a connection string of the form jdbc:hive2://host:port/;auth=noSasl. For example, you might use:
To connect to an instance of Impala that requires Kerberos authentication, use a connection string of the form jdbc:hive2://host:port/;principal=principal_name. The principal must be the same user principal you used when starting Impala. For example, you might use:
To connect to an instance of Impala that requires LDAP authentication, use a connection string of the form jdbc:hive2://host:port/db_name;user=ldap_userid;password=ldap_password. For example, you might use: