Wrong metric type for minio_s3_time_ttfb_seconds_distribution?

[MalKeshar]

Problem: it is not possible to use histogram_quantile function on minio_s3_time_ttfb_seconds_distribution

Assumption: minio probably use wrong metric type for request duration.

1. According prometheus documentation for distribution should be used summary and histogram metrics type
   https://prometheus.io/docs/practices/histograms/

2. According https://github.com/minio/minio/blob/master/cmd/metrics-v2.go
   request duration is the only minio distribution metric, which use gauge.

Other distributions use Histogram.

sizeDistribution = "size_distribution"
versionDistribution = "version_distribution"
ttfbDistribution = "ttfb_seconds_distribution"

...
Name: sizeDistribution,
Help: "Distribution of object sizes in the bucket, includes label for the bucket name",
Type: histogramMetric,

Name: versionDistribution,
Help: "Distribution of object sizes in the bucket, includes label for the bucket name",
Type: histogramMetric,

Name: ttfbDistribution,
Help: "Distribution of the time to first byte across API calls",
Type: gaugeMetric,

Name: latencyMilliSec,
Help: "Replication latency in milliseconds",
Type: histogramMetric,

3. Even data of this metric looks in tsdb as cumulative counter, not a gauge, it always goes up.

I search for answer in github issues, but didn't find it.

It was previously asked in
#14293
#12540
but there was no answer

By any chance is it possible that it's some kind of mistake? Is there any information for such decision?
Thank you.

[harshavardhana]

This issue was fixed incorrectly, this requires an overhaul in the way we calculate. We had to move back to gaugeMetric for now.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 15 days if no further activity occurs. Thank you for your contributions.