During December, GitHub experienced no incidents causing service downtime. This report provides a follow-up analysis on the November 27 incident documented in the previous month’s availability report.
Follow-up: November 27 Incident (16:04 UTC, lasting one hour and one minute)
Root Cause: Investigation revealed “an edge case that triggered a large number of GitHub App token requests. This caused abnormal levels of replication lag within one of our MySQL clusters” supporting GitHub Actions.
Impact: “The database lag resulted in the failure of some of those token requests because the database replicas did not have up to date information,” causing some GitHub Actions job failures.
Remediation: “We are updating the queries to prevent large quantities of token requests from overloading the database servers in the future.”