A debugger is useless against a bug that only shows up live, scattered across hundreds of requests a second with no reliable way to reproduce it, and most tools engineers know were built for a different problem. This book teaches the skill that replaces the debugger: reading evidence from metrics, logs, thread dumps, heap snapshots, and traces, then building hypotheses you can test cheaply without making things worse. It works through incidents covering memory leaks, deadlocks, performance cliffs, races that will not reproduce on demand, retry storms, and cascading failures, each followed by the technique underneath it. A field guide maps symptoms to likely causes, and a closing chapter covers writing a postmortem that changes the system, not the person.



Imad Muratspahic is an independent author of practical how-to guides, technical handbooks, history and fiction. The books aim to be clear, honest and useful from the first page.