Apache Flink is a powerful thing to work with but, my, it does test one’s patience sometimes ;-) Particularly if you’re new to using it, understanding how to troubleshoot problems that arise is an important survival skill to acquire. This talk will be a hands-on demonstration packed full of practical tips to solving some of the most common problems that can occur in Flink SQL. We’ll spend time looking at JAR files - what they are, how to find the one you need, and how to check you’ve put it in the right place. After that I’ll show you some of the really funky head-scratching problems that I’ve encountered, including debugging Iceberg, Flink, and Hive Metastore…on Docker containers. Along with all of this I’ll show you some of my favourite bash-based troubleshooting tools. You’ll leave this talk equipped with the knowledge of how to methodically troubleshooting Flink SQL problems, understanding of the primary moving parts of the stack—and some nice additions to your command-line toolkit.