RJDBC Cassandra -> Error in .jfindClass(as.character(driverClass)[1]) : class not found

Question

I am trying to connect R to Cassandra and I am getting the following error - even though I explicitly add this directory folder to the classpath before I run the code (and I also point to the classpath within the statement)? Thanks for any help!

require(RJDBC)

.jaddClassPath("C:\\Users\\atrombley\\Desktop\\R\\")
cassdrv <- JDBC("org.apache.cassandra.cql.jdbc.CassandraDriver",
                "C:\\Users\\atrombley\\Desktop\\R\\cassandra-jdbc-1.2.5.jar")

Error in .jfindClass(as.character(driverClass)[1]) : class not found

Answer 1

In my case, the database driver was missing from the location named in my call of JDBC(). Just added the Jar to that location and it works! For example:

JDBC(driverClass="com.vertica.jdbc.Driver", classPath="C:/Program Files/Vertica Systems/JDBC/vertica-jdbc-7.2.1-0.jar")

This helpful clue resulted from turning on debugging:

.jclassLoader()$setDebug(1L)

as advised here: https://github.com/s-u/RJDBC/issues/26

Answer 2

Cassandra JDBC driver v1.2.5 does not work with Cassandra 2.* and is very very deprecated, still uses the thrift API and does only connect to a single node.

You should grab the new version I made that uses the Datastax Java Driver underneath : https://github.com/adejanovski/java-driver

Here's a link to the compiled version with all the necessary dependencies : https://drive.google.com/file/d/0B7fwX0DqcWSTLUFqSEMxVFVWY2M/view?usp=sharing

Use the appropriate driver class and JDBC url as shown on this page : https://github.com/adejanovski/java-driver/tree/2.1/driver-jdbc

Another more efficient option (though I'm not familiar with R) should be to use R on Spark and access Cassandra through the spark-cassandra connector provided by Datastax.