PCA Querying & Visualization 2

Question 1

What does the `rate()` function calculate when applied to a counter metric?

Accepted Answer

The per-second average rate of increase over the range window

Answer

`rate()` calculates the per-second average rate of increase of a counter over the specified time range window.

Question 2

What is the key difference between `irate()` and `rate()` in PromQL?

Accepted Answer

`irate()` uses only the last two data points while `rate()` averages across the full range

Answer

`irate()` calculates the instantaneous rate using only the last two samples in the range, making it more responsive to sudden spikes than `rate()`.

Question 3

What does the `increase()` function return for a counter over a given range vector?

Accepted Answer

The total increase in the counter value over the time range

Answer

`increase()` returns the total increase in a counter's value over the specified range, accounting for counter resets.

Question 4

Which label matcher in PromQL uses a regular expression to match label values?

Accepted Answer

`=~`

Answer

The `=~` matcher selects labels matching a provided regular expression, while `!~` selects labels that do NOT match the regex.

Question 5

What does `absent(up{job="myapp"})` return when the time series EXISTS?

Accepted Answer

An empty vector (no data)

Answer

`absent()` returns an empty vector when the input time series exists, and returns a vector with value 1 only when the series is missing.

(PCA) Prometheus Certified Associate Practice Test