DEA-C01 Data Ingestion and Transformation Practice Question
A data engineer is troubleshooting a Kinesis Data Firehose delivery stream that ingests JSON log data from web servers. The stream is configured to transform records with an AWS Lambda function and deliver to an Amazon S3 bucket. Recently, the stream has been failing with 'InvalidData' errors. Which action should the engineer take to resolve the issue?
⚠ Common exam trap
Test-takers frequently confuse 'InvalidData' errors with S3 permission issues or buffer configuration problems, but the error specifically points to a failure in the data transformation step, not the delivery destination or batching settings.
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
✓
Check the CloudWatch Logs for the Lambda function to identify transformation errors.
The 'InvalidData' error in Kinesis Data Firehose typically indicates that the Lambda function used for data transformation is failing or returning malformed records. By checking the CloudWatch Logs for the Lambda function, the engineer can identify specific transformation errors, such as incorrect JSON parsing, missing fields, or exceptions, which cause Firehose to reject the records. This is the most direct troubleshooting step because Firehose relies on the Lambda function to return valid transformed data in the expected format.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Verify the S3 bucket policy allows Firehose to write.
Why it's wrong here
Permission errors would show as 'AccessDenied', not 'InvalidData'.
- ✗
Increase the buffer size and interval in the Firehose delivery stream.
Why it's wrong here
Buffer settings do not resolve data transformation errors.
- ✗
Change the data format to CSV in the Firehose configuration.
Why it's wrong here
Changing format may not solve the transformation issue.
- ✓
Check the CloudWatch Logs for the Lambda function to identify transformation errors.
Why this is correct
Lambda errors are logged in CloudWatch and can reveal why transformation fails.
Visual reference
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 |
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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.