Arithmetic functions

Arithmetic functions apply a mathematical operation to every sample value of the input vector, preserving all labels.

abs

Applies abs to every sample value of the input vector, preserving all labels. Absolute value of every sample.

Syntax

abs(<expr>)

Example

Measure how far the query-service goroutine count moved in 30 minutes, regardless of direction.

abs(delta(go_goroutines{app_kubernetes_io_name="query-service"}[30m]))

ceil

Applies ceil to every sample value of the input vector, preserving all labels. Rounds every sample up to the nearest integer.

Syntax

ceil(<expr>)

Example

Round the Kloudfuse goroutine total up to the next thousand.

ceil(sum(go_goroutines{app_kubernetes_io_instance="kfuse"}) / 1000)

clamp_max

Applies clamp_max to every sample value of the input vector, preserving all labels. Limits every sample to a maximum.

Syntax

clamp_max(<expr>, <max>)

Example

Cap the Kloudfuse goroutine total at 10,000.

clamp_max(sum(go_goroutines{app_kubernetes_io_instance="kfuse"}), 10000)

clamp_min

Applies clamp_min to every sample value of the input vector, preserving all labels. Limits every sample to a minimum.

Syntax

clamp_min(<expr>, <min>)

Example

Treat any decrease in goroutines as zero, keeping only growth.

clamp_min(delta(go_goroutines{app_kubernetes_io_name="query-service"}[30m]), 0)

clamp

Applies clamp to every sample value of the input vector, preserving all labels. Limits every sample to a min–max range.

Syntax

clamp(<expr>, <min>, <max>)

Example

Cap the Kloudfuse goroutine total at 10,000 and floor it at 0 — outliers no longer stretch the chart axis.

clamp(sum(go_goroutines{app_kubernetes_io_instance="kfuse"}), 0, 10000)

exp

Applies exp to every sample value of the input vector, preserving all labels. e raised to each sample value.

Syntax

exp(<expr>)

Example

Compute e^1 — the result is Euler’s number, ≈ 2.718.

exp(vector(1))

floor

Applies floor to every sample value of the input vector, preserving all labels. Rounds every sample down to the nearest integer.

Syntax

floor(<expr>)

Example

Round the Kloudfuse goroutine total down to the previous thousand.

floor(sum(go_goroutines{app_kubernetes_io_instance="kfuse"}) / 1000)

ln

Applies ln to every sample value of the input vector, preserving all labels. Natural logarithm of every sample.

Syntax

ln(<expr>)

Example

Take the natural log of the Kloudfuse goroutine total — useful for charting values that span orders of magnitude.

ln(sum(go_goroutines{app_kubernetes_io_instance="kfuse"}))

log10

Applies log10 to every sample value of the input vector, preserving all labels. Base-10 logarithm of every sample.

Syntax

log10(<expr>)

Example

Find the order of magnitude of the Kloudfuse goroutine total.

log10(sum(go_goroutines{app_kubernetes_io_instance="kfuse"}))

log2

Applies log2 to every sample value of the input vector, preserving all labels. Base-2 logarithm of every sample.

Syntax

log2(<expr>)

Example

Compute log2(1024) — the result is 10.

log2(vector(1024))

round

Applies round to every sample value of the input vector, preserving all labels. Rounds every sample to the nearest multiple.

Syntax

round(<expr> [, <to-nearest>])

Example

Round the Kloudfuse goroutine total to the nearest hundred.

round(sum(go_goroutines{app_kubernetes_io_instance="kfuse"}), 100)

sgn

Applies sgn to every sample value of the input vector, preserving all labels. Sign of every sample: -1, 0, or 1.

Syntax

sgn(<expr>)

Example

Reduce the 30-minute goroutine trend to its direction: growing (1), flat (0), or shrinking (-1).

sgn(delta(go_goroutines{app_kubernetes_io_name="query-service"}[30m]))

sqrt

Applies sqrt to every sample value of the input vector, preserving all labels. Square root of every sample.

Syntax

sqrt(<expr>)

Example

Compute the square root of 256 — the result is 16.

sqrt(vector(256))