PDE Maintaining and Automating Data Workloads Practice Question
You want to monitor the latency of messages in a Pub/Sub subscription. Which Cloud Monitoring metric should you use to see the age of the oldest unacknowledged message?
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
✓
pubsub.googleapis.com/subscription/oldest_unacked_message_age
The metric 'subscription/oldest_unacked_message_age' measures the age (in seconds) of the oldest unacknowledged message in a subscription. This helps track processing lag. The other metrics measure different aspects: num_undelivered_messages is count, not age; topic metrics are irrelevant for subscription lag; publish_latency is about publishing, not consumption.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
pubsub.googleapis.com/subscription/oldest_unacked_message_age
Why this is correct
This metric directly shows the age of the oldest unacknowledged message, indicating processing latency.
- ✗
pubsub.googleapis.com/subscription/num_undelivered_messages
Why it's wrong here
This metric gives the count of undelivered messages, not their age.
- ✗
pubsub.googleapis.com/topic/send_request_count
Why it's wrong here
This is a topic metric for publish requests, not subscription latency.
- ✗
pubsub.googleapis.com/topic/publish_latency
Why it's wrong here
This measures the time to publish messages, not the age of unacked messages.
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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.