- A
Increase the data retention period of the stream
Why wrong: Increasing retention keeps data longer but does not help processing keep up.
- B
Decrease the number of shards in the stream
Why wrong: Fewer shards mean less capacity, making the backlog worse.
- C
Increase the number of shards in the stream
More shards increase throughput, allowing the consumer to process faster.
- D
Reduce the data retention period of the stream
Why wrong: Reducing retention does not affect processing speed; it only deletes data sooner.
Question 465 of 1,755
Reduce Kinesis Iterator Age by Increasing Shards
This MLS-C01 practice question tests your understanding of data engineering. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company captures streaming data from IoT devices using Amazon Kinesis Data Streams. The data is consumed by a custom application that processes records in near real-time. Recently, the application has been falling behind, and the stream is showing increased 'iterator age' metrics in CloudWatch. Which action is MOST likely to reduce the iterator age?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 'iterator age' metric in Amazon Kinesis Data Streams measures the time between the oldest unread record in a shard and the current time. An increasing iterator age indicates that consumers are reading data slower than it is being produced. Increasing the number of shards increases the stream's total read capacity, allowing the custom application to process records in parallel and reduce the backlog.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the data retention period of the stream
Why it's wrong here
Increasing retention keeps data longer but does not help processing keep up.
- ✗
Decrease the number of shards in the stream
Why it's wrong here
Fewer shards mean less capacity, making the backlog worse.
- ✓
Increase the number of shards in the stream
Why this is correct
More shards increase throughput, allowing the consumer to process faster.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Reduce the data retention period of the stream
Why it's wrong here
Reducing retention does not affect processing speed; it only deletes data sooner.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Common misconception: increasing retention period helps with processing backlogs, but retention only affects data durability, not throughput; the correct solution is to scale shards to match consumer throughput.
Detailed technical explanation
How to think about this question
Each shard in Kinesis Data Streams supports up to 5 read transactions per second, with a maximum total read rate of 2 MB per second. By increasing the number of shards, you linearly scale the read throughput, enabling the consumer application to fetch records from more shards concurrently. This is analogous to increasing partitions in Apache Kafka to improve consumer group parallelism.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this MLS-C01 question test?
Data Engineering — This question tests Data Engineering — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the number of shards in the stream — The 'iterator age' metric in Amazon Kinesis Data Streams measures the time between the oldest unread record in a shard and the current time. An increasing iterator age indicates that consumers are reading data slower than it is being produced. Increasing the number of shards increases the stream's total read capacity, allowing the custom application to process records in parallel and reduce the backlog.
What should I do if I get this MLS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more ways this is tested on MLS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. 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?
easy- A.Reduce the data retention period of the stream
- ✓ B.Increase the number of shards in the Kinesis data stream
- C.Increase the maximum concurrency of the AWS Lambda function that processes the stream
- D.Use Amazon Kinesis Data Firehose to deliver data to Amazon S3
Why B: Option B is correct because 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.
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Last reviewed: Jul 4, 2026
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.
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