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Question
Your DynamoDB-backed user-events table starts returning ProvisionedThroughputExceededException / throttling at 08:50 and your ingest pipeline's error rate climbs to 15%. CloudWatch shows ConsumedWriteCapacity flat at the provisioned ceiling while ThrottledRequests spikes. Interestingly, total table-level consumed capacity is below the provisioned total, but one partition is hot. A new feature began writing all events for a campaign under a single partition key (campaign_id) this morning. How do you triage and mitigate?
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
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