The answer is to use a smaller environment size, such as selecting a small environment instead of a medium one. This directly reduces the baseline cost of the underlying compute resources, as Cloud Composer environments are billed based on the worker and scheduler nodes provisioned. Additionally, deleting old and unused DAG files lowers the scheduler’s parsing load—since the scheduler scans the DAG folder every 30 seconds by default—reducing CPU and memory consumption and further cutting operational expenses. On the Google Professional Data Engineer exam, this question tests your understanding of how environment sizing and DAG maintenance directly impact cost, often appearing as a multi-select scenario where you must identify actions that trim resource usage without sacrificing functionality. A common trap is confusing storage costs with compute costs; remember that reducing DAG parsing overhead lowers scheduler compute, not storage. Memory tip: “Smaller size and fewer files save scheduler cycles and dollars.”
PDE Practice Question: Building and operationalizing data processing systems
This PDE practice question tests your understanding of building and operationalizing data processing systems. 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.
Which THREE actions reduce the cost of a Cloud Composer environment?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Delete old and unused DAG files to reduce scheduler load
Option A is correct because deleting old and unused DAG files reduces the number of DAGs the scheduler must parse and evaluate. The Cloud Composer scheduler scans the DAG folder every 30 seconds by default; fewer DAG files mean lower CPU and memory consumption, directly reducing the cost of the environment's compute resources.
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.
✓
Delete old and unused DAG files to reduce scheduler load
Why this is correct
Less load means fewer resources needed.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use standard network tier instead of premium
Why it's wrong here
Network tier affects data transfer, not Composer cost.
✓
Set up a maintenance window to shut down the environment during idle hours
Why this is correct
Shutting down saves costs during non-operational hours.
Related concept
Read the scenario before looking for a memorised answer.
✓
Use a smaller environment size (e.g., small instead of medium)
Why this is correct
Smaller environment has fewer resources and lower cost.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase the number of schedulers for higher throughput
Why it's wrong here
More schedulers increase cost.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse scaling up (Option E) with cost optimization, not realizing that adding schedulers increases resource consumption and cost, while the correct cost-saving actions involve reducing resource usage or shutting down idle capacity.
Detailed technical explanation
How to think about this question
Under the hood, Cloud Composer runs on Google Kubernetes Engine (GKE) with autoscaling node pools. Deleting unused DAGs reduces the scheduler's parsing overhead, which can lower the number of nodes required in the cluster. In a real-world scenario, a team with hundreds of legacy DAGs saw a 30% reduction in monthly costs after cleaning up stale DAGs and reducing the scheduler's `dagbag_size`.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Building and operationalizing data processing systems — This question tests Building and operationalizing data processing systems — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Delete old and unused DAG files to reduce scheduler load — Option A is correct because deleting old and unused DAG files reduces the number of DAGs the scheduler must parse and evaluate. The Cloud Composer scheduler scans the DAG folder every 30 seconds by default; fewer DAG files mean lower CPU and memory consumption, directly reducing the cost of the environment's compute resources.
What should I do if I get this PDE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This PDE practice question is part of Courseiva's free Google Cloud 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 PDE exam.
Question Discussion
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