MLS-C01 Data Engineering Practice Question
A company uses Amazon Kinesis Data Streams to ingest clickstream data from a website. The data is consumed by a custom application that runs on Amazon EC2 instances. The company notices that the consumer application is falling behind the producer, causing data to be throttled. Which action should the company take to improve the consumer's 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 data stream
Increasing the number of shards increases the stream's read capacity, allowing more consumers to read in parallel and improving throughput. Option A is wrong because reducing the data retention period does not increase read throughput; it only affects how long data is stored. Option C is wrong because Lambda concurrency is applicable only to Lambda functions, not to the custom EC2 application consuming the stream. Option D is wrong because Amazon Kinesis Data Firehose is a different service for delivering streaming data to destinations like S3, and it does not improve the throughput of the existing EC2 consumer.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Reduce the data retention period of the stream
Why it's wrong here
Retention period does not affect throughput.
- ✓
Increase the number of shards in the Kinesis data stream
Why this is correct
More shards increase the stream's read and write capacity.
- ✗
Increase the maximum concurrency of the AWS Lambda function that processes the stream
Why it's wrong here
The scenario uses EC2, not Lambda. Also, concurrency is limited by shard count.
- ✗
Use Amazon Kinesis Data Firehose to deliver data to Amazon S3
Why it's wrong here
Firehose is for delivery, not for improving consumer throughput.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This MLS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the MLS-C01 exam.