Connecting to remote Mapr Hive via JDBC

Question

This question is similar, but not the same, as Hive JDBC getConnection does not return . Yet this is about a remote connection. Also the metastore is present in the directory in which the hiveserver2 was started.

We have a running mapr cluster on a remote machine. I would like to connect to Hive on this cluster using Java JDBC.

Hence we started the hive server:

/opt/mapr/hive/hive-0.11/bin/hiveserver2

The output of the server process does not contain any error messages. It listens on port 10000 as reported by netstat.

I try to connect to the server as described in https://cwiki.apache.org/confluence/display/Hive/HiveClient, thereby replacing localhost by the server name where the hiveserver2 is running:

Connection con = 
  DriverManager.getConnection("jdbc:hive://myserver.example.com:10000/default", "", "");

Yet the program hangs exactly at this statement. It does not seem to get a connection.

Possibly I need to supply a username and password?

Initially I had used the driver org.apache.hadoop.hive.jdbc.HiveDriver.

Yet it seems like I should be using the driver org.apache.hive.jdbc.HiveDriver if the hive2 server is running. Now I am getting the following Exception:

Exception in thread "main" java.sql.SQLException: Could not establish connection to jdbc:hive2://myserver.example.com:10000/default: Required field 'client_protocol' is unset! Struct:TOpenSessionReq(client_protocol:null)
at org.apache.hive.jdbc.HiveConnection.openSession(HiveConnection.java:246)
at org.apache.hive.jdbc.HiveConnection.<init>(HiveConnection.java:132)
at org.apache.hive.jdbc.HiveDriver.connect(HiveDriver.java:105)
at java.sql.DriverManager.getConnection(DriverManager.java:579)
at java.sql.DriverManager.getConnection(DriverManager.java:221)
at HiveJdbcClient.main(HiveJdbcClient.java:22)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: org.apache.thrift.TApplicationException: Required field 'client_protocol' is unset! Struct:TOpenSessionReq(client_protocol:null)
at org.apache.thrift.TApplicationException.read(TApplicationException.java:108)
at org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:71)
at org.apache.hive.service.cli.thrift.TCLIService$Client.recv_OpenSession(TCLIService.java:144)
at org.apache.hive.service.cli.thrift.TCLIService$Client.OpenSession(TCLIService.java:131)
at org.apache.hive.jdbc.HiveConnection.openSession(HiveConnection.java:237)
... 10 more

Answer 1

I had the same problem and was able to get around it by adding the correct dependency to my pom.xml file. I was getting the latest apache release of hive from maven central and switched to using the cdh4 release from the cloudera repo. So, what you are seeing may be a symptom of having the wrong hive-jdbc dependency. Here's the maven snippet I added to my pom file:

<repository>
<id>cloudera</id>
<url>https://repository.cloudera.com/artifactory/cloudera-repos/</url>
</repository>
...
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-jdbc</artifactId>
<version>0.10.0-cdh4.3.2</version>
</dependency>

Here's a link about the cloudera repo.

Also, adding the ";auth=noSasl" to the URL made my application hang so I removed it.

Answer 2

I think you need to specify the username. Also itshould be hive2 not hive since you are using hiveserver2. Try modifying your connection url:

Connection con = 
  DriverManager.getConnection("jdbc:hive2://myserver.example.com:10000/default", "<user>", "");

Its given in the link Hive2

Hope this helps...!!!