A binstub with a bad “shebang” line can cause your application to function improperly. This article explains binstubs, shebang lines, and the common errors that come from improperly generated binstubs.
H12 errors are especially difficult. They can be equally caused by a lack of throughput capacity (need to add more dynos), an extremely long-running request or requests that back up others, or some shared resource like a database receiving higher
The Ruby language metrics feature, currently in public beta, adds Ruby-specific time series metrics to Application Metrics to provide additional insights into memory health.
Sometimes a Ruby app generates a segfault - usually caused by an extension. This article illustrates the typical causes, and how to find the faulty gem.
Ruby applications should gracefully shut down when a dyno shuts down, or is restarted. Sensitive operations should be wrapped in an `ensure` clause, though care must be taken to have this clause terminate.