The topics that were covered in cca159 are mostly:
Impala (1 or 2 questions)
The questions will be mostly scenarios based. Please have a though hands on in the cloudera environment before going to the exam.
Read the questions thoroughly and know where the answers should be placed in the path.
Practical tips for attempting the exam.
The questions are lengthy and the time taken to execute the query will be more sometimes. In such cases, dont wait it the query completes. While the query is running, attempt another question and keep the answer ready. Work in multiple windows for different questions.
All the very Best.