PCA Promql Practice Question
An operator writes the query sum(rate(http_requests_total[5m])) without any aggregation clauses. What is the output format?
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
✓
An instant vector containing a single element with no labels.
Aggregations without a by or without clause aggregate all time series into a single global vector with no labels.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A range vector spanning 5 minutes.
Why it's wrong here
rate() converts range vectors into instant vectors.
- ✓
An instant vector containing a single element with no labels.
Why this is correct
Correct. Global aggregation drops all labels and returns a single time series.
- ✗
An instant vector preserving all original metric labels.
Why it's wrong here
Unspecified aggregation drops all distinctive labels.
- ✗
A scalar value representing the exact floating-point result.
Why it's wrong here
Aggregations return instant vectors, not raw scalars, unless explicitly coerced.
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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.