DEA-C01 practice question: Throttling, fan-out and replay (2 of 2)
Data Ingestion and Transformation A free question from our original DEA-C01 practice exam. Try it, then open the answer to see why each option is right or wrong.
A pet insurer's claim-events stream in Kinesis Data Streams feeds a fraud model and a reporting job. Last week a bug in the reporting job forced a replay, and the team found that records older than one day were already gone.
The stream still uses the default retention period. From now on, the team must be able to reprocess up to three days of events with the same consumer code, keeping the stream and the consumers as they are.
Which change meets this requirement?
Choose one answer.
AA. Increase the number of shards so that the stream can hold more records before the oldest ones expire.
BB. Set the reporting consumer's checkpoint back to the start of the stream, because the stream keeps records until they have been read.
CC. Turn on enhanced fan-out for the reporting consumer, so it can read older records from each shard at a higher rate and with its own throughput.
DD. Extend the stream's retention to at least three days, so that a consumer can later restart from a timestamp in that window.
Show the answer and explanation
Answer: D
A. Wrong: Shard count controls throughput, not how long records are kept. Adding shards leaves the default retention in place, so the oldest events would still be gone.
B. Wrong: Kinesis does not keep records until they are read, so moving the checkpoint has no effect on expired records. The consumer could only restart from whatever the retention window still holds.
C. Wrong: Enhanced fan-out changes read throughput for each consumer, not how long records stay in the stream. The reporting job still could not read records that have already expired.
D. Right: Correct. Kinesis Data Streams keeps records for 24 hours by default, and extended retention lets the stream hold them for up to 365 days. With at least three days of retention, the reporting consumer can restart from a timestamp inside that window after a future fix. Learn more: Change the data retention period (opens in a new tab)
Explanation
A replay can only read records that the stream still holds. The default retention is 24 hours, so being able to replay three days needs extended retention set to cover that window; records that already expired cannot be recovered. Shard count, checkpoints and fan-out do not change how long records are kept.
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