PCD Integrating Google Cloud services Practice Question
You are designing a data pipeline that ingests streaming data from IoT devices using Cloud IoT Core, processes it with Dataflow, and stores results in BigQuery. The data volume is expected to be 10 GB per day with occasional spikes. You need to minimize processing latency and cost. Which configuration should you choose for the Dataflow pipeline?
⚠ Common exam trap
Google Cloud often tests the misconception that batch mode is cheaper for streaming data, but the trap here is that batch mode incurs higher latency and requires manual triggering, making it unsuitable for real-time IoT pipelines despite lower compute cost per GB.
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
✓
Use streaming mode with streaming engine enabled and 2 workers.
Streaming mode with Streaming Engine is designed for low-latency, continuous data ingestion from IoT Core, and setting 2 workers minimizes cost while handling the expected 10 GB/day volume with occasional spikes through autoscaling. Streaming Engine offloads state management to the backend, reducing worker overhead and improving latency, making it ideal for this use case. Option B (Dataflow Prime) is not optimal because, although it supports both batch and streaming pipelines and offers automatic optimization, for a small, predictable workload like 10 GB/day, the overhead of Prime's automation may not justify the cost. Manual tuning with Streaming Engine and a small initial worker count is more cost-effective while still providing low latency. Autoscaling can handle spikes without over-provisioning, making C a better fit.
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 streaming mode with autoscaling and maximum workers set to 10.
Why it's wrong here
Too many workers for 10 GB/day; increases cost.
- ✗
Use Dataflow Prime for automatic optimization.
Why it's wrong here
Dataflow Prime is for batch pipelines.
- ✓
Use streaming mode with streaming engine enabled and 2 workers.
Why this is correct
Streaming engine reduces latency and cost for moderate throughput.
- ✗
Use batch mode with a fixed number of workers to reduce cost.
Why it's wrong here
Batch mode is not for streaming.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCD 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 PCD exam.