MLS-C01 Data Engineering Practice Question
A company uses Amazon Kinesis Data Streams to collect IoT sensor data. The stream has 4 shards. A consumer application reads from the stream using the Kinesis Client Library (KCL). The application processes records and stores them in Amazon DynamoDB. Recently, the data volume has increased, and the consumer is falling behind. Which action should the team take to increase the processing throughput?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the number of shards in the Kinesis stream.
Increase the number of shards in the Kinesis stream. Kinesis Data Streams throughput is determined by the number of shards; each shard provides 1 MB/s or 1000 records/s for reading. Since the consumer is falling behind, increasing shards directly increases the read throughput. Option A is incorrect because adding more consumer instances without increasing shards will not improve throughput; KCL ensures each shard is processed by one worker, so extra workers are idle. Option B is incorrect because increasing DynamoDB write capacity may reduce throttling but does not address the root cause of low read throughput from Kinesis. Option C is incorrect because increasing the data retention period does not affect the rate at which data can be read.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy additional consumer instances using the same application name.
Why it's wrong here
KCL will distribute shards among workers, but with only 4 shards, extra workers will be idle.
- ✗
Increase the write capacity of the DynamoDB table.
Why it's wrong here
This helps if writes are throttled, but the bottleneck is reading from the stream.
- ✗
Increase the data retention period of the stream to 7 days.
Why it's wrong here
Retention period does not affect ingestion or consumption throughput.
- ✓
Increase the number of shards in the Kinesis stream.
Why this is correct
More shards provide more read capacity units and allow more parallel consumers.
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