hardMultiple SelectObjective-mapped
PDE Practice Question: A company uses Cloud Pub/Sub with pull…
A company uses Cloud Pub/Sub with pull subscriptions to process orders. The application requires at-least-once delivery and the ability to process orders in order per customer_id. Which THREE features should they configure? (Choose three.)
⚠ Common exam trap
A common misconception is that push subscriptions can support message ordering, but in reality, only pull subscriptions with ordering enabled can guarantee per-key order, and push subscriptions always deliver messages unordered.
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
✓
Configure a dead letter topic
A dead letter topic is correct because it allows undeliverable messages to be moved to a separate topic after all delivery attempts are exhausted, preventing message loss while still enabling at-least-once delivery semantics. This ensures that problematic messages do not block the processing of subsequent messages in the same ordering key group, which is critical when message ordering is enabled.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure a dead letter topic
Why this is correct
Allows failed messages to be stored without blocking subsequent messages.
- ✗
Use a push subscription with a HTTPS endpoint
Why it's wrong here
Push subscriptions can deliver messages, but ordering is achieved via configuration.
- ✓
Enable ordering keys on the topic
Why this is correct
Required for ordered delivery per key.
- ✓
Enable message ordering on the subscription
Why this is correct
Ensures messages are delivered in order per key.
- ✗
Set the subscription's ackDeadline to 600 seconds
Why it's wrong here
Long ack deadline may cause delays but not necessary for ordering.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.