Tracer ammunition (tracers) are bullets or cannon caliber projectiles that are built with a small pyrotechnic charge in their base. Ignited by the burning powder, the pyrotechnic composition burns very brightly, making the projectile visible to the naked eye. This enables the shooter to follow the projectile trajectory to make aiming corrections.
Tracer Bullet is also a private investigator, an alter ego of Calvin in the comic strip Calvin and Hobbes. :)
The Tracer Bullets gem makes studying the performance of your Rails app from its development log file a lot easier.
Performance tuning a Rails app is still pretty damn hard. There are great tools out there like New Relic, and even Rails own performance tests, but still, I find areas where I’m tearing my hair...