PDE Maintaining and Automating Data Workloads Practice Question
A data engineer needs to monitor a Pub/Sub-based streaming pipeline. Which two Cloud Monitoring metrics should be used to detect a backlog of unprocessed messages? (Choose two.)
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
✓
subscription/oldest_unacked_message_age
The 'subscription/num_undelivered_messages' metric shows the number of messages not yet acknowledged, and 'subscription/oldest_unacked_message_age' indicates how long messages have been waiting. Both help detect backlog.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
subscription/oldest_unacked_message_age
Why this is correct
This metric shows the age of the oldest unacknowledged message, indicating backlog depth.
- ✗
topic/byte_cost
Why it's wrong here
This is a billing metric, not for monitoring backlog.
- ✓
subscription/num_undelivered_messages
Why this is correct
This metric directly shows the count of unprocessed messages.
- ✗
topic/send_request_count
Why it's wrong here
This metric measures publish requests, not backlog.
- ✗
subscription/ack_message_count
Why it's wrong here
This metric counts acknowledgements, not backlog.
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JA
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.