On Monday March 31st, 2026, between 13:53 UTC and 21:23 UTC the Pull Requests service experienced elevated latency and failures. On average, the error rate was 0.15% and peaked at 0.28% of requests to the service. This was due to a change in garbage collection (GC) settings for a Go-based internal service that provides access to Git repository data. The changes caused more frequent GC activity and elevated CPU consumption on a subset of storage nodes, increasing latency and failure rates for some internal API operations.

We mitigated the incident by reverting the GC changes. To prevent future incidents and improve time to detection and mitigation, we are instrumenting additional metrics and alerting for GC-related behavior, improving our visibility into other signals that could cause degraded impact of this type, and updating our best practices and standards for garbage collection in Go-based services.

Posted Mar 31, 2026 - 21:23 UTC

The degradation affecting Pull Requests has been mitigated. We are monitoring to ensure stability.

Posted Mar 31, 2026 - 21:16 UTC

We continue to see a small subset of repositories experiencing timeouts and elevated latency in Pull Requests, affecting under 1% of requests.

Posted Mar 31, 2026 - 21:12 UTC

Error rates remain elevated across multiple pull request endpoints. We are pursuing multiple potential mitigations.

Posted Mar 31, 2026 - 19:28 UTC

We continue to experience elevated error rates affecting Pull Requests. An earlier fix resolved one component of the issue, but some users may still encounter intermittent timeouts when viewing or interacting with pull requests. Our teams are actively investigating the remaining causes.

Posted Mar 31, 2026 - 18:42 UTC

We identified an issue causing increased errors when accessing Pull Requests. The mitigation is being applied across our infrastructure and we will continue to provide updates as the mitigation rolls out.

Posted Mar 31, 2026 - 17:16 UTC

We are seeing recovery in latency and timeouts of requests related to pull requests, even though 500s are still elevated. While we are continuing to investigate, we are applying a mitigation and expect further recovery after it is applied.

Posted Mar 31, 2026 - 16:35 UTC

We are continuing to investigate increased 500 errors affecting GitHub services. You may experience intermittent failures when using Pull Requests and other features. We are actively working to identify and resolve the underlying cause.

Posted Mar 31, 2026 - 16:15 UTC

We are investigating increased 500 errors affecting GitHub services. You may experience intermittent failures when using Pull Requests and other features. We are actively working to identify and resolve the underlying cause.

Posted Mar 31, 2026 - 15:39 UTC

We are seeing a higher than average number of 500s due to timeouts across GitHub services. We have a potential mitigation in flight and are continuing to investigate.

Posted Mar 31, 2026 - 15:06 UTC

We are investigating reports of degraded performance for Pull Requests

Posted Mar 31, 2026 - 15:05 UTC