DEA-C01 Data Ingestion and Transformation Practice Question
Network Topology
Refer to the exhibit. A data engineer runs the AWS CLI command to describe a Glue job. The job is expected to process new data incrementally using job bookmarks. However, the job reprocesses all data every time it runs. What is the MOST likely reason?
⚠ Common exam trap
It's easy for candidates to assume bookmarks are controlled only by the job configuration setting (`job-bookmark-enable`) and overlook the critical role of `transformation_ctx` in the ETL script, which is a common oversight in AWS Glue exam questions.
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
✓
The ETL script does not use the 'transformation_ctx' parameter in its DynamicFrame transformations.
AWS Glue job bookmarks rely on the `transformation_ctx` parameter to track state. Without it, Glue cannot identify which data has already been processed, causing the job to reprocess all data on every run. The `transformation_ctx` must be passed to each DynamicFrame transformation (e.g., `apply_mapping`, `filter`, `join`) to enable bookmark-based incremental processing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The job bookmark option is set to 'job-bookmark-enable' but should be 'job-bookmark-disable'.
Why it's wrong here
'job-bookmark-enable' is precisely the setting that activates incremental processing, so the described value is already correct; the fault lies elsewhere, such as a changed transformation context or source path. It is tempting because the option names the bookmark argument, but disabling bookmarks would cause reprocessing rather than fix it.
- ✗
The job's MaxRetries is set to 0, which disables bookmarks.
Why it's wrong here
MaxRetries controls how often a failed job run is retried; it has no bearing on bookmark state, which is stored per job run and keyed on source path and transformation context. It is tempting because a zero value looks like a disabled feature, but bookmarks are governed by the --job-bookmark-option argument, not retry counts.
- ✓
The ETL script does not use the 'transformation_ctx' parameter in its DynamicFrame transformations.
Why this is correct
Job bookmarks rely on the `transformation_ctx` argument to persist state per transformation; without it, Glue cannot track which data each DynamicFrame has already processed, so every run reads the full dataset. Supplying a unique `transformation_ctx` for each source and transformation satisfies the incremental-processing requirement.
- ✗
The Glue job's command name is 'glueetl', which does not support job bookmarks.
Why it's wrong here
The glueetl command supports job bookmarks; the limitation applies to certain source types and to jobs whose transformation context changes between runs. It is tempting because command name and bookmark support are related, but glueetl is the standard Spark ETL command and does not itself prevent incremental reads.
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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. Refer to the exhibit. A data engineer runs this AWS CLI command to create a Glue job. The job processes JSON files in an S3 bucket and writes Parquet files to another bucket. After the first successful run, the job re-processes all input files instead of only new files. What is the most likely cause?
hard- A.The ScriptLocation points to an incorrect S3 path.
- B.The --max-retries parameter is set to 0.
- ✓ C.The job script does not implement job bookmark support.
- D.The IAM role lacks permissions to read bookmark state.
Why C: The command sets '--job-bookmark-enable' but if the job script does not use the bookmark APIs or implement bookmark support, Glue will not track processed files and will reprocess all input on each run. Option A is incorrect because the ScriptLocation is valid and does not affect bookmark behavior. Option B is incorrect because max-retries does not control reprocessing. Option D is incorrect because the IAM role is specified and permissions for bookmark state are not explicitly shown, but the lack of bookmark support in the script is the issue.
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.