MLS-C01 Data Engineering Practice Question
A company uses Amazon Kinesis Data Streams with a shard count of 5. The data producer sends 1000 records per second, each 1 KB in size. The consumer application reads from the stream using the Kinesis Client Library (KCL) and processes records. The consumer is experiencing high latency and falling behind. What is the most effective way to improve consumer throughput?
⚠ Common exam trap
It's easy for candidates to confuse enhanced fan-out (which provides dedicated throughput per consumer) with solving throughput issues, but fail to realize that with only 5 shards, even dedicated throughput per shard is insufficient for high-volume consumption, making shard scaling the correct solution.
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 stream.
The consumer is falling behind because it cannot process records fast enough. The Kinesis Client Library (KCL) typically runs one consumer thread per shard, so with only 5 shards there are only 5 parallel consumers. To improve throughput, the number of shards should be increased to allow more parallel processing. Options like enhanced fan-out would improve read throughput per consumer but do not increase parallelism; the bottleneck here is processing speed, not read throughput. Increasing shards directly increases the number of consumers and thus overall throughput.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Switch to Kinesis Data Analytics for processing.
Why it's wrong here
Incorrect: Data Analytics is for SQL queries, not for improving consumer throughput.
- ✗
Use enhanced fan-out to dedicate read throughput to the consumer.
Why it's wrong here
Incorrect: Enhanced fan-out is beneficial when multiple consumers read the same stream; for a single consumer, it does not increase throughput.
- ✗
Increase the record size to 5 KB.
Why it's wrong here
Incorrect: Record size does not affect consumer throughput.
- ✓
Increase the number of shards in the stream.
Why this is correct
Correct: More shards provide more read capacity and allow parallel processing.
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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.