How to import HDFS Data into Apache Solr

The Apache Solr platform is a popular, blazing-fast, open source enterprise search solution built on Apache Lucene.

Apache Solr is equipped with the Data Import Handler (DIH), which can import data from databases and, XML, CSV, and JSON files. When paired with the CData JDBC Driver for HDFS, you can easily import HDFS data to Apache Solr. In this article, we show step-by-step how to use CData JDBC Driver in Apache Solr Data Import Handler and import HDFS data for use in enterprise search.

Create an Apache Solr Core and a Schema for Importing HDFS

1. Run Apache Solr and create a Core.

   > solr create -c CDataCore

   For this article, Solr is running as a standalone instance in the local environment and you can access the core at this URL: http://localhost:8983/solr/#/CDataCore/core-overview
2. Create a schema consisting of "field" objects to represent the columns of the HDFS data to be imported and a unique key for the entity. LastModifiedDate, if it exists in HDFS, is used for incremental updates. If it does not exist, you cannot do the deltaquery in the later section. Save the schema in the managed-schema file created by Apache Solr.

	HDFSUniqueKey
	
	
	
	
	
	
	
	 
	

👁 Define schema in Solr for HDFS data.

3. Install the CData HDFS JDBC Driver. Copy the JAR and license file (cdata.hdfs.jar and cdata.jdbc.hdfs.lic) to the Solr directory.
   
   • CData JDBC JAR file: C:\Program Files\CData\CData JDBC Driver for HDFS ####\lib
   • Apache Solr: solr-8.5.2\server\lib

Now we are ready to use HDFS data in Solr.

Define an Import of HDFS to Apache Solr

In this section, we walk through configuring the Data Import Handler.

1. Modify the Config file of the created Core. Add the JAR file reference and add the DIH RequestHander definition.

   	
   
   	<lib dir="${solr.install.dir:../../../..}/dist/" regex="solr-dataimporthandler-.*\.jar" />
   
   	<requestHandler name="/dataimport" class="org.apache.solr.handler.dataimport.DataImportHandler">
   		<lst name="defaults">
   			<str name="config">solr-data-config.xml</str>
   		</lst>
   	</requestHandler>

2. Next, create a solr-data-config.xml at the same level. In this article, we retrieve a table from HDFS, but you can use a custom SQL query to request data as well. The Driver Class and a sample JDBC Connection string are in the sample code below.

   	
   	<dataConfig>
   		<dataSource driver="cdata.jdbc.hdfs.HDFSDriver" url="jdbc:hdfs:Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;User=root;">
   		</dataSource> 
   		<document> 
   			<entity name="Files" 
   				query="SELECT Id,HDFSColumn1,HDFSColumn2,HDFSColumn3,HDFSColumn4,HDFSColumn5,HDFSColumn6,HDFSColumn7,LastModifiedDate FROM Files"
   				deltaQuery="SELECT Id FROM Files where LastModifiedDate >= '${dataimporter.last_index_time}'"
   				deltaImportQuery="SELECT Id,HDFSColumn1,HDFSColumn2,HDFSColumn3,HDFSColumn4,HDFSColumn5,HDFSColumn6,HDFSColumn7,LastModifiedDate FROM Files where Id=${dataimporter.delta.Id}">
   				<field column="Id" name="Id" ></field>
   				<field column="HDFSColumn1" name="HDFSColumn1" ></field>
   				<field column="HDFSColumn2" name="HDFSColumn2" ></field>
   				<field column="HDFSColumn3" name="HDFSColumn3" ></field>
   				<field column="HDFSColumn4" name="HDFSColumn4" ></field>
   				<field column="HDFSColumn5" name="HDFSColumn5" ></field>
   				<field column="HDFSColumn6" name="HDFSColumn6" ></field>
   				<field column="HDFSColumn7" name="HDFSColumn7" ></field>
   				<field column="LastModifiedDate" name="LastModifiedDate" ></field> 
   			</entity>
   		</document>
   	</dataConfig>

3. In the query section, set the SQL query that select the data from HDFS. deltaQuery and deltaImportquery define the ID and the conditions when using incremental updates from the second import of the same entity.
4. After all settings are done, restart Solr.

   	> solr stop -all
   	> solr start
   	

Run a DataImport of HDFS Data.

1. Execute DataImport from the URL below:
   http://localhost:8983/solr/#/CDataCore/dataimport//dataimport 👁 Load HDFS data to Solr using Data Import.
   
2. Select the "full-import" Command, choose the table from Entity, and click "Execute." 👁 Execute full import in Solr.
   
3. Check the result of the import from the Query. 👁 Check the full import result of HDFS.
   
4. Try an incremental update using deltaQuery. Modify some data in the original HDFS data set. Select the "delta-import" command this time from DataImport window and click "Execute." 👁 Execute Delta import in Solr.
   
5. Check the result of the incremental update. 👁 Check the delta import result of HDFS.
   

Using the CData JDBC Driver for HDFS you are able to create an automated import of HDFS data into Apache Solr. Download a free, 30 day trial of any of the hundreds of CData JDBC Drivers and get started today.