The 6 Characters That Could Bring Down Your Rails App

It all started with a ping from one of the team leads who noticed a recurring exception in Sentry. At the same time, DataDog showed the Postgres CPU utilization was spiking.Based on the Sentry logs, the team lead thought this exception was caused by a specific deploy, but they couldn’t find anything in the most recent commits. Then they asked me to look into it. I was new to this project, so I had the fresh eyes benefit.The first thing I did was look at the exception in Sentry, which pointed to the problematic line of code, which had been introduced about a year earlier. I immediately knew what the problem was when I saw the infamous 6 characters:.