In this chapter, we learned various details of Impala troubleshooting through Cloudera Manager: log analysis, checking events, console output, and so on. We have seen how Cloudera Manager can be very useful to troubleshoot various problems in Impala as well as how you can look for potential performance-specific issues in logs. A manual study of the log is very important to learn more about Impala execution and once you understood it very well, you can troubleshoot the problem just by revisiting the log. There are several other factors that can be considered as potential problems that impact Impala performance. Sometimes, the Hadoop cluster itself is very busy performing several MapReduce jobs submitted by other issues. This can consume significant resources from nodes in the Hadoop cluster and ultimately cause problems in Impala execution. Networking issues, such as a congested network, slow performing network cards, and network limitations of any kind could also cause potential performance issues with Impala. In most of these situations, cluster and logs analysis is one of the best options to find the root cause. Then, apply the specific information that you learned in this chapter to solve your problem.

Chapter 7, Advanced Impala Concepts, covers various advanced concepts that will extend Impala to the next level and make it much more useful. In the next chapter, we will cover a few advanced topics such as HBase integration and HDFS file formats to increase your knowledge of Impala.