The SQL tab in the Spark UI displays all the accumulator values per operator. You should be able to access the SQL tab at http://localhost:4040/SQL/. It displays all the SQL query executions and underlying information by default. However, the SQL tab displays the details of the SQL query execution only after a query has been selected.

A detailed discussion on SQL is out of the scope of this chapter. Interested readers should refer to http://spark.apache.org/docs/latest/sql-programming-guide.html#sql for more on how to submit an SQL query and see its result output.