Enable the Presto JDBC Driver in KNIME

One of the strengths of the CData JDBC Driver for Presto is its cross-platform support, enabling integration with major BI tools. Follow the procedure below to access Presto data in KNIME and to create a chart from Presto data using the report designer.

Define a New JDBC Connection to Presto Data

1. Install the Report Designer extension: Click File -> Install KNIME Extensions, and filter on "Report".
2. In a new workflow, click File -> Preferences and expand the KNIME -> Databases node to add cdata.jdbc.presto.jar. The driver JAR is located in the lib subfolder of the installation directory.
3. In the Node Repository view, expand the Database -> Read/Write node and drag a Database Reader onto the workflow editor.

4. Double-click the Database Reader and set the following properties:

   • Database Driver: In the menu, select the driver name, cdata.jdbc.presto.PrestoDriver

   • Database URL: Enter the connection properties. The JDBC URL begins with jdbc:presto: and is followed by a semicolon-separated list of connection properties.

     Set the Server and Port connection properties to connect, in addition to any authentication properties that may be required.

     To enable TLS/SSL, set UseSSL to true.

     Authenticating with LDAP

     In order to authenticate with LDAP, set the following connection properties:

     • AuthScheme: Set this to LDAP.
     • User: The username being authenticated with in LDAP.
     • Password: The password associated with the User you are authenticating against LDAP with.

     Authenticating with Kerberos

     In order to authenticate with KERBEROS, set the following connection properties:

     • AuthScheme: Set this to KERBEROS.
     • KerberosKDC: The Kerberos Key Distribution Center (KDC) service used to authenticate the user.
     • KerberosRealm: The Kerberos Realm used to authenticate the user with.
     • KerberosSPN: The Service Principal Name for the Kerberos Domain Controller.
     • KerberosKeytabFile: The Keytab file containing your pairs of Kerberos principals and encrypted keys.
     • User: The user who is authenticating to Kerberos.
     • Password: The password used to authenticate to Kerberos.

     Built-in Connection String Designer

     For assistance in constructing the JDBC URL, use the connection string designer built into the Presto JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

     java -jar cdata.jdbc.presto.jar

     Fill in the connection properties and copy the connection string to the clipboard.

     

     When you configure the JDBC URL, you may also want to set the Max Rows connection property. This will limit the number of rows returned, which is especially helpful for improving performance when designing reports and visualizations.

     A typical JDBC URL is below.

     jdbc:presto:Server=127.0.0.1;Port=8080;
   • User Name: The username used to authenticate.
   • Password: The password used to authenticate.
   • SQL Statement: Enter an SQL query in the SQL Statement box or double-click a table. This article uses the query below to create a chart: SELECT FirstName, LastName FROM Customer WHERE Id = '123456789'

5. Test the connection by clicking Fetch Metadata.

   
6. Connect the Database Reader to a Data to Report node to supply the dataset to a range of data visualization controls. Click Execute and then click Edit Report at the top of the workflow to open the report designer perspective.
7. You can now generate reports based on live data. To create a chart, drag the chart control from the palette to the report designer. In the resulting wizard, you can use the filtering and aggregation controls available in KNIME.

Troubleshooting

The following list shows how to resolve common errors:

• Encountered duplicate row Id "Row1": To resolve this error, add the following to the knime.ini file located in your KNIME installation directory:-Dknime.database.fetchsize=0