Analyze Redshift Data in R

Access Redshift data with pure R script and standard SQL on any machine where R and Java can be installed. You can use the CData JDBC Driver for Redshift and the RJDBC package to work with remote Redshift data in R. By using the CData Driver, you are leveraging a driver written for industry-proven standards to access your data in the popular, open-source R language. This article shows how to use the driver to execute SQL queries to Redshift and visualize Redshift data by calling standard R functions.

Install R

You can match the driver's performance gains from multi-threading and managed code by running the multithreaded Microsoft R Open or by running open R linked with the BLAS/LAPACK libraries. This article uses Microsoft R Open 3.2.3, which is preconfigured to install packages from the Jan. 1, 2016 snapshot of the CRAN repository. This snapshot ensures reproducibility.

Load the RJDBC Package

To use the driver, download the RJDBC package. After installing the RJDBC package, the following line loads the package:

Connect to Redshift as a JDBC Data Source

You will need the following information to connect to Redshift as a JDBC data source:

• Driver Class: Set this to cdata.jdbc.redshift.RedshiftDriver
• Classpath: Set this to the location of the driver JAR. By default this is the lib subfolder of the installation folder.

The DBI functions, such as dbConnect and dbSendQuery, provide a unified interface for writing data access code in R. Use the following line to initialize a DBI driver that can make JDBC requests to the CData JDBC Driver for Redshift:

You can now use DBI functions to connect to Redshift and execute SQL queries. Initialize the JDBC connection with the dbConnect function.

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.

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

Below is a sample dbConnect call, including a typical JDBC connection string:

Schema Discovery

The driver models Redshift APIs as relational tables, views, and stored procedures. Use the following line to retrieve the list of tables:

Execute SQL Queries

You can use the dbGetQuery function to execute any SQL query supported by the Redshift API:

You can view the results in a data viewer window with the following command:

Plot Redshift Data

You can now analyze Redshift data with any of the data visualization packages available in the CRAN repository. You can create simple bar plots with the built-in bar plot function: