8. Hive integration

Starting with Spring for Apache Hadoop 2.3 and Hive 1.0 support for HiveServer1 and the Hive Thrift client have been dropped. You should instead use HiveServer2 and the JDBC driver for Hive.

The SHDP programming model for HiveServer1 have been updated to use the JDBC driver instead of directly using the Thrift client. If you have existing code you will have to modify it if you use the HiveClient directly. If you use the HiveTemplate then you should be able to simply update your configuration files to use the JDBC driver.

8.1 Starting a Hive Server

The new HiveServer2 now supports multi-user access and is typically run in the Hadoop cluster. See the Hive Project for details.

8.2 Using the Hive JDBC Client

We provide a dedicated namespace element for configuring a Hive client (that is Hive accessing a server node through JDBC). You also need a hiveDataSource using the JDBC driver for HiveServer2:

<!-- by default, the definition name is 'hiveClientFactory' -->
<hive-client-factory id="hiveClientFactory" hive-data-source-ref="hiveDataSource"/>
<beans:bean id="hiveDriver" class="org.apache.hive.jdbc.HiveDriver"/>
<beans:bean id="hiveDataSource" class="org.springframework.jdbc.datasource.SimpleDriverDataSource">
  <beans:constructor-arg name="driver" ref="hiveDriver"/>
  <beans:constructor-arg name="url" value="jdbc:hive2://localhost:1000"/>

8.3 Running a Hive script or query

Like the rest of the Spring Hadoop components, a runner is provided out of the box for executing Hive scripts, either inlined or from various locations through hive-runner element:

<hdp:hive-runner id="hiveRunner" run-at-startup="true">
     DROP TABLE IF EXITS testHiveBatchTable;
     CREATE TABLE testHiveBatchTable (key int, value string);
   <hdp:script location="hive-scripts/script.q"/>

The runner will trigger the execution during the application start-up (notice the run-at-startup flag which is by default false). Do note that the runner will not run unless triggered manually or if run-at-startup is set to true. Additionally the runner (as in fact do all runners in SHDP) allows one or multiple pre and post actions to be specified to be executed before and after each run. Typically other runners (such as other jobs or scripts) can be specified but any JDK Callable can be passed in. For more information on runners, see the dedicated chapter.

8.3.1 Using the Hive tasklet

For Spring Batch environments, SHDP provides a dedicated tasklet to execute Hive queries, on demand, as part of a batch or workflow. The declaration is pretty straightforward:

<hdp:hive-tasklet id="hive-script">
     DROP TABLE IF EXITS testHiveBatchTable;
     CREATE TABLE testHiveBatchTable (key int, value string);
   <hdp:script location="classpath:org/company/hive/script.q" />

The tasklet above executes two scripts - one declared as part of the bean definition followed by another located on the classpath.

8.4 Interacting with the Hive API

For those that need to programmatically interact with the Hive API, Spring for Apache Hadoop provides a dedicated template, similar to the aforementioned JdbcTemplate. The template handles the redundant, boiler-plate code, required for interacting with Hive such as creating a new HiveClient, executing the queries, catching any exceptions and performing clean-up. One can programmatically execute queries (and get the raw results or convert them to longs or ints) or scripts but also interact with the Hive API through the HiveClientCallback. For example:

<hdp:hive-client-factory ... />
<!-- Hive template wires automatically to 'hiveClientFactory'-->
<hdp:hive-template />

<!-- wire hive template into a bean -->
<bean id="someBean" class="org.SomeClass" p:hive-template-ref="hiveTemplate"/>
public class SomeClass {

  private HiveTemplate template;

  public void setHiveTemplate(HiveTemplate template) { this.template = template; }

  public List<String> getDbs() {
      return hiveTemplate.execute(new HiveClientCallback<List<String>>() {
         public List<String> doInHive(HiveClient hiveClient) throws Exception {
            return hiveClient.get_all_databases();

The example above shows a basic container configuration wiring a HiveTemplate into a user class which uses it to interact with the HiveClient Thrift API. Notice that the user does not have to handle the lifecycle of the HiveClient instance or catch any exception (out of the many thrown by Hive itself and the Thrift fabric) - these are handled automatically by the template which converts them, like the rest of the Spring templates, into `DataAccessException`s. Thus the application only has to track only one exception hierarchy across all data technologies instead of one per technology.