Incident Review: What Comes Up Must First Go Down

On July 25th, 2023, Honeycomb experienced a significant outage affecting all user-facing components for over an hour, marking the most severe incident since acquiring paying customers. The outage stemmed from a routine cluster switch intended to bypass a bug, which instead uncovered a subtle implementation flaw that halted database writes and led to a system crash. Attempts to resolve the issue revealed a deadlock in MySQL's internals, exacerbated by increased database load due to cache failures. The recovery process involved implementing circuit breakers, failing over to a database replica, and manually updating schema timestamps, although this introduced some data inaccuracies. The incident highlighted how efforts to avoid minor bugs inadvertently contributed to the outage, prompting Honeycomb to explore architectural changes and strengthen its caching mechanisms to prevent future occurrences. Despite the challenges, the company aims to improve response times and mitigate similar incidents by learning from the experience and refining its systems and processes.