A retail chain streams point-of-sale events into an Amazon Kinesis data stream that feeds a demand-forecasting feature pipeline. The stream is in provisioned mode with 16 shards, and producers use the store's region code as the partition key. There are four regions, and the Northeast region generates about 70% of all events. During sales, producers receive ProvisionedThroughputExceeded errors even though the stream's total incoming data is under 40% of its combined shard capacity.