response_latency_ms_bucket

[ghost]

Can you please explain the meaning of metric response_latency_ms_bucket. Is that just a name change for response_latency_ms?

$ linkerd diagnostics proxy-metrics -n linkerd deploy/linkerd-controller | grep -B 2 -m 1 response_latency_ms_bucket
# HELP response_latency_ms Elapsed times between a request's headers being received and its response stream completing
# TYPE response_latency_ms histogram
response_latency_ms_bucket{direction="inbound",target_addr="0.0.0.0:4191",tls="true",client_id="prometheus.linkerd-viz.serviceaccount.identity.linkerd.cluster.local",status_code="200",le="1"} 548421

response_latency_ms: A histogram of response latencies. This measurement reflects the time-to-first-byte (TTFB) by recording the elapsed time between the proxy processing a request’s headers and the first data frame of the response. If a response does not include any data, the end-of-stream event is used. The TTFB measurement is used so that Linkerd accurately reflects application behavior when a server provides response headers immediately but is slow to begin serving the response body.

Thank you.

[olix0r]

This is a Prometheus histogram:

A histogram with a base metric name of exposes multiple time series during a scrape:

• cumulative counters for the observation buckets, exposed as <basename>_bucket{le="<upper inclusive bound>"}
• the total sum of all observed values, exposed as <basename>_sum
• the count of events that have been observed, exposed as _count (identical to <basename>_bucket{le="+Inf"} above)