Troubleshooting the Connection
To show driver activity from query execution to network traffic, use Logfile and Verbosity. The examples of common connection errors below show how to use these properties to get more context. Contact the support team for help tracing the source of an error or circumventing a performance issue.
- Authentication errors: Typically, recording a Logfile at Verbosity 4 is necessary to get full details on an authentication error.
The certificate presented by the server cannot be validated: This error indicates that the driver cannot validate the server's certificate through the chain of trust. (If you are using a self-signed certificate, there is only one certificate in the chain).
To resolve this error, you must verify yourself that the certificate can be trusted and specify to the driver that you trust the certificate. One way you can specify that you trust a certificate is to add the certificate to the trusted system store; another is to set SSLServerCert.
- Database: A default database to use when one is not supplied in the SQL query. This enables using table names without having to specify database.tablename in the query.
- PageSize: The number of results to pull per page from Apache Impala when selecting data.
- QueryPassthrough: Indicates if the query should be passed to Impala as-is. When QueryPassthrough is set to false (default), the CData JDBC Driver for Apache Impala will attempt to modify the query to conform to Impala required format.