I tried to rebuild with the new DB framework what @tobias.koetter suggested in this post for the legacy framework: Call Stored Procedure, Read Workflow Credentials in Java Snippet - #5 by tobias.koetter
This worked just fine for me:
In DB SQL Executor I create the procedure (might not be needed in your case):
DROP PROCEDURE simpleproc;
CREATE PROCEDURE simpleproc
AS
SELECT count(*)
FROM knimeTest;
and with DB Query Reader I execute the procedure and retrieve the result set:
EXEC simpleproc