PCA Promql Practice Question
You want to find the maximum value of a gauge metric across all instances over a 1-hour sliding window. Which function accomplishes this?
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
✓
max_over_time(node_memory_usage_bytes[1h])
The max_over_time() function evaluates the maximum value of all data points in a specified range vector for each time series.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
max(node_memory_usage_bytes[1h])
Why it's wrong here
Aggregation operators like max cannot take range vectors directly without an over_time function.
- ✓
max_over_time(node_memory_usage_bytes[1h])
Why this is correct
Correct. max_over_time finds the maximum value across the range vector.
- ✗
topk(1, node_memory_usage_bytes[1h])
Why it's wrong here
topk returns the largest elements of an instant vector, not over a range window.
- ✗
max_with_range(node_memory_usage_bytes, 1h)
Why it's wrong here
max_with_range is not a valid function name.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official CNCF / Linux Foundation exam blueprint
This PCA practice question is part of Courseiva's free CNCF / Linux Foundation 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 PCA exam.