PCA (Prometheus Certified Associate) sample exam question with answer 237

Question:
What is the difference between the increase and delta query functions?

1. increase operates on change over time while delta gives the current difference (delta) between two different metrics
2. increase operates on counter metrics while delta operates on gauge metrics
3. increase gives the positive change while delta can be negative. In other words, increase is syntactic sugar for abs(delta(<expression>))
4. increase operates on gauge metrics while delta operates on counter metrics

Answer:
B - is the correct answer
A - is incorrect as both increase and delta operate on range vectors to calculate change over time
C - while it is true that increase must yield a nonnegative value (as a result of increase only operating on monotonically increasing counter metrics), the given syntactic sugar expression is not true as the increase function should be used with counters, not delta
D - is incorrect as it is actually delta that operates on gauge metrics while increase operates on counter metrics