The following is a tale of how we discovered and fixed a variety of reliability and performance issues in our Node.js application that were caused by Node.js event loop lag. The discovery At around 11pm local time (10pm UTC) on Thursday June 20, we were alerted to some issues in our production services powering the Trigger.dev cloud, as some of our dashboard/API instances started crashing. We hopped on to our AWS production dashboard and saw that the CPU usage of our instances were really high a...