On March 30, 2026, between 10:11 UTC and 13:25 UTC, GitHub Actions experienced degraded performance. During this time, approximately 2.65% of workflow jobs triggered by pull request events experienced start delays exceeding 5 minutes. The issue was caused by replication lag on an internal database cluster used by Actions, which triggered write throttling in our database protection layer and slowed job queue processing.
The replication lag originated from planned maintenance to scale the internal database. Newly added database hosts triggered guardrails in the throttling layer, restricting write throughput. The incident was mitigated by excluding the new hosts from replication delay calculations.
To prevent recurrence, we have updated our maintenance procedures to ensure new hosts are excluded from throttling assessments during scaling operations. Additionally, we are investing in automation to streamline this type of maintenance activity.
