While Couchbase provides many great features to import and export data from Couchbase to Hadoop there is some functionality that the plugin doesn't implement in Sqoop. Here's a list of what isn't implemented.
Querying: You cannot run queries on Couchbase. All tools that attempt to do this will fail with a NotSupportedException.
list-databases tool: Even though Couchbase is a multi-tenant system that allows for multiple databases. There is no way of listing these databases from Sqoop.
eval-sql tool: Couchbase doesn't use SQL so this tool will not work.