DEA-C01 Data Ingestion and Transformation Practice Question
A company is using Amazon Kinesis Data Streams to ingest real-time clickstream data. The data is consumed by a fleet of EC2 instances running a custom application that processes the records and writes to DynamoDB. The application is experiencing high latency and records are being processed slower than they are produced. The stream has 5 shards. Which action would MOST effectively improve processing speed?
⚠ Common exam trap
Candidates often think adding more consumers (EC2 instances) will automatically speed up processing, but they fail to recognize that each shard's read throughput is fixed, so without increasing shards, additional consumers cannot consume more data in parallel.
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.
The bottleneck is the number of shards in the Kinesis stream. Each shard provides a fixed read capacity of 2 MB/s and 5 read transactions per second. With only 5 shards, the total read throughput is limited regardless of how many EC2 instances consume the data. Increasing the number of shards increases the total read capacity, allowing more records to be consumed in parallel and reducing processing latency.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use the Kinesis Client Library (KCL) to automatically distribute shards among instances.
Why it's wrong here
The Kinesis Client Library only coordinates shard leases and checkpointing across consumers; it does not raise the five-shard throughput ceiling causing the backlog. It is tempting because KCL is the standard way to distribute shards among instances, and it would be correct when lease handling, not raw capacity, is the problem.
- ✗
Increase the EC2 instance size to provide more CPU and memory.
Why it's wrong here
Vertical scaling cannot lift the read ceiling, since each shard caps at 2 MB/s and five shards cap the whole consumer fleet regardless of instance size. It is tempting because larger instances help CPU-bound processing, and it would be correct if the bottleneck were application compute rather than shard throughput.
- ✗
Add more EC2 instances consuming from the same stream without changing shard count.
Why it's wrong here
Each shard can be consumed by only one consumer per application; extra instances will be idle.
- ✓
Increase the number of shards in the Kinesis stream.
Why this is correct
Kinesis shard count sets the stream's total ingest and per-shard consumer throughput ceiling. With five shards saturated, adding shards raises aggregate capacity and lets the EC2 fleet's consumers process records faster, addressing the production-versus-processing imbalance directly.
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Same concept, more angles
1 more way this is tested on DEA-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 is using Amazon Kinesis Data Streams with a Lambda consumer to process clickstream data. The data rate is high and the Lambda function is falling behind, resulting in increased processing latency. What is the MOST effective way to improve throughput?
medium- A.Increase the memory allocated to the Lambda function.
- B.Increase the Lambda function timeout.
- C.Use Kinesis Data Firehose instead of Lambda.
- ✓ D.Increase the number of shards in the Kinesis stream.
Why D: Increasing the number of shards in the Kinesis stream increases the stream's total read capacity, allowing more concurrent Lambda invocations to process records in parallel. Since each shard supports up to 5 read transactions per second and a maximum of 2 MB/s read throughput, adding shards directly raises the aggregate throughput, enabling the Lambda consumer to keep up with the high data rate.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-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 DEA-C01 exam.