IBM Fluid Query 1.7.2

Troubleshooting connection problems

If you encounter problems running the fqConfigure.sh script to define connections to service providers, there are some suggested troubleshooting steps.

If the fqConfigure.sh script returns a Java error such as java.lang.NoClassDefFoundError: org.apache.<class name>, you might be missing a Java JAR file that is required for the connection to the Hadoop service provider. Review the class name shown in the error message, and see JDBC drivers for predefined data connectors for more information about the JDBC files required for each connection.
If the fqConfigure.sh script returns an error similar to Execution failed due to a distribution protocol error that caused deallocation of the conversation. A DRDA Data Stream Syntax Error was detected. Reason: 0x3. ERRORCODE=-4499, SQLSTATE=58009, check your port number specified in the command. If you did not specify a --port value, your Hadoop service provider may not be using the default port. If you specified a --port value, you might have specified an incorrect value.
For problems with Kerberos:
If you use Kerberos authentication, make sure that the system time on your Netezza® appliance matches the system time for your Kerberos realm.
If you have problems using Kerberos authentication to connect to a service provider, try connecting to the Kerberos realm by its domain name (not the IP address). For example, try the following commands:
- $ ping your.realm.com
- $ telnet your.realm.com 88
- $ cat /etc/hosts to check the host definitions for your site
If you have problems connecting to an Impala or Hive server, try the following commands:
- $ telnet your.impala.com 21050
- $ telnet your.hive.com 10000
- $ cat /etc/hosts to check the host definitions for your site
Check that your hostname resolves to your external IP address that the Kerberos server uses and not 127.0.0.1:
- $ hostname to display the system hostname
- $ ping hostname where hostname is the value obtained in the previous command.
- $ cat /etc/hosts to check the host definitions for your site
Connection configuration to Hive on BigInsights fails when using SSL:
1. You might see the following error:
```
javax.net.ssl.SSLKeyException: RSA premaster secret error
```
  which is a common Java problem. To solve it, download the Unrestricted SDK JCE policy files for IBM Java available at https://www-01.ibm.com/marketing/iwm/iwm/web/reg/download.do?source=jcesdk&lang=en_US&S_PKG=13_01&cp=UTF-8 and update the files on NPS in the following locations:
  /nz/export/ae/languages/java/java_sdk/host/jre/lib/security/local_policy.jar
  
  /nz/export/ae/languages/java/java_sdk/host/jre/lib/security/US_export_policy.jar
2. When using the predefined Hive connector, you might see the following error:
```
Could not open client transport with JDBC Uri:
      jdbc:hive2:// hive_server_host_name :10000/default;SSL=true;:
      Invalid status 21
```
  which is caused by the fact that IBM Fluid Query is generating property SSL=true in upper case letters, instead of lower case. To avoid this issue, you can use generic connector which allows you to specify the connection URL on your own:
  1. Create the configuration XML file (the following example uses variables):
```
<?xml version="1.0" encoding="UTF-8"?>
<connection>
  <driverClass>org.apache.hive.jdbc.HiveDriver</driverClass>
  <classPath>/nz/export/ae/products/fluidquery/libs/cloudera/hive/</classPath>
  <connectionURL>jdbc:hive2://${HOSTNAME}:${PORT}/default;ssl=true;</connectionURL>
  <jdbc-properties>
              <property>
                      <name>user</name>
                      <value>${USERNAME}</value>
              </property>
              <property>
                      <name>password</name>
                      <value>${PASSWORD}</value>
              </property>
  </jdbc-properties>
</connection>
```
  2. When running fqConfigure, modify provider and service command arguments to generic, and, using connectionXmlPath, specify the path to the XML file that you created:
```
./fqConfigure.sh --host hive_server_host_name --port 10000 --provider generic 
--service generic --connectionXmlPath /your/path/to/the/file.xml --config your_file_name 
--username your_user --password your_password --ssl
```

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