https://acadgild.com/blog/querying-hive-using-apache-drill

Apache Drill is an open source software framework which has been derived from Google’s Dremel System available as an infrastructure service called Google BigQuery.

The specilaity of the Drill is to scale up to 10,000 servers or more and to be able to process petabytes of data and trillions of records in seconds.

Drill has been popularly used as a SQL query engine for Big Data exploration.

It is designed to support high-performance analysis on the semi-structured and rapidly evolving data coming from modern Big Data applications and the same time it provides the familiarity and ecosystem of ANSI SQL, the industry-standard query language.

Drill provides plug-and-play integration with existing Apache Hive and ApacheHBasedeployments.

In this post, we will be discussing how to install apache Drill in embedded mode and how to configure Hive storage plug-in for Drill to query onHivetables.

Installing Apache Drill

The first step to do is to download Apache Drill. You can do this using the below link:

www.apache.org/dyn/closer.lua?filename=drill/drill-1.6.0/apache-drill-1.6.0.tar.gz&action=download

After downloading, move to the file in the downloaded folder, and type the command

tar -xvzf apache-drill-1.6.0.tar.gz

After the extraction of the tar file, you will be able to seeapache-drill-1.6.0.

That’s it! Drill has been installed in your single node system.

Next, let’s configure Drill to query on Hive tables.

Note: Hive should be pre-installed in your cluster

Now, type the commandhive –service metastorein one terminal and open another terminal and startDrill.To do this, move into the Drill installed folder and go into the bin folder and then type the command./drill-embedded

Setting Hive storage plugin for Drill:

Next, open your browser and typelocalhost:8047to enter into Drill’s Web UI.

Now, click on ‘Storage’ and enable Hive.

Now, click on ‘Update’ and do the changes as specified. By default, the configuration properties will look like as shown below:

 {
       type:"hive",
       enabled: true,
       configProps : {
         "hive.metastore.uris" : "thrift://<metastore_host>:<port>",
         "fs.default.name" : "hdfs://<host>:<port>/",
         "hive.metastore.sasl.enabled" : "false",
         "hive.server2.enable.doAs" : "true",
         "hive.metastore.execute.setugi" : "true"
       }
      }

Next, in theHive.metastore.uris, enter the thrift host name and port number. In our case, host name islocalhostand the port number is default for all it is9083.

Infs.default.name,give the HDFS complete path; in our case, it ishdfs://localhost:9000

Finally, the configuration properties will look as shown below:

{
"type": "hive",
"enabled": true,
"configProps": {
"hive.metastore.uris": "thrift://localhost:9083",
"javax.jdo.option.ConnectionURL": "jdbc:derby:;databaseName=../sample-data/drill_hive_db;create=true",
"hive.metastore.warehouse.dir": "/tmp/drill_hive_wh",
"fs.default.name": "hdfs://localhost:9000",
"hive.metastore.sasl.enabled": "false"
}
}

For performing simple operations on the tables in Hive, we need to create one table in Hive. Let’s create one table in Hive, now.

create table olympic(athelete STRING,age INT,country STRING,year STRING,closing STRING,sport STRING,gold INT,silver INT,bronze INT,total INT) row format delimited fields terminated by '\t' stored as textfile;

Here, we are creating a table with name “olympic” and the schema of the table is as specified above. The data inside the above input file is delimited by tab space.As explained earlier, the file format is specified as TEXTFILE at the end.The schema of the table created above can be checked usingdescribe olympic;

We can load data into the created table as:

load data local inpath ‘path of your file’ into table olympic;

The same is shown in the figure below:

We have successfully loaded our input file data into our table in TEXTFILE format.

Now, let’s perform one basic SELECT operation on the data as shown below:

Select athlete from olympic;

The data retrieved is as shown in the below image:

Now, go to the terminal where Apache Drill is running; here type the commanduse hiveto make Drill use Hive schema.

Now, you will be able to perform all the Hive queries using Drill. First, let’s check the table which we have created in Hive through Drill.

You can see the schema of the table in Hive using Drill.

Now, let us perform some queries on the data. Let’s find out the average age of the athletes who has participated in Olympics.

Command:select AVG(age) from olympic

You can see that the result has been displayed on the screen. The average age of the athletes is26.405433646812956

Hope this post has been helpful in understanding the concept of querying Hive table using Apache Drill. In case of any questions, feel free to comment below and we will get back to you at the earliest.

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