Enable the Redshift JDBC Driver in KNIME

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

Define a New JDBC Connection to Redshift 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.redshift.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.redshift.RedshiftDriver

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

     To connect to Redshift, set the following:

     • Server: Set this to the host name or IP address of the cluster hosting the Database you want to connect to.
     • Port: Set this to the port of the cluster.
     • Database: Set this to the name of the database. Or, leave this blank to use the default database of the authenticated user.
     • User: Set this to the username you want to use to authenticate to the Server.
     • Password: Set this to the password you want to use to authenticate to the Server.

     You can obtain the Server and Port values in the AWS Management Console:

     1. Open the Amazon Redshift console (http://console.aws.amazon.com/redshift).
     2. On the Clusters page, click the name of the cluster.
     3. On the Configuration tab for the cluster, copy the cluster URL from the connection strings displayed.

     Built-in Connection String Designer

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

     java -jar cdata.jdbc.redshift.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:redshift:User=admin;Password=admin;Database=dev;Server=examplecluster.my.us-west-2.redshift.amazonaws.com;Port=5439;
   • 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 ShipName, ShipCity FROM Orders

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