Merge pull request #10140 from David-N-Perkins/ISS-9910

Issue 9910

promql/functions.go

@@ -791,7 +791,7 @@ func funcPredictLinear(vals []parser.Value, args parser.Expressions, enh *EvalNo
 func funcHistogramQuantile(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
 	q := vals[0].(Vector)[0].V
 	inVec := vals[1].(Vector)
-	sigf := signatureFunc(false, enh.lblBuf, excludedLabels...)
+	sigf := signatureFunc(false, enh.lblBuf, labels.BucketLabel)
 
 	if enh.signatureToMetricWithBuckets == nil {
 		enh.signatureToMetricWithBuckets = map[string]*metricWithBuckets{}
@@ -810,11 +810,14 @@ func funcHistogramQuantile(vals []parser.Value, args parser.Expressions, enh *Ev
 			continue
 		}
 		l := sigf(el.Metric)
+		// Add the metric name (which is always removed) to the signature to prevent combining multiple histograms
+		// with the same label set. See https://github.com/prometheus/prometheus/issues/9910
+		l = l + el.Metric.Get(model.MetricNameLabel)
 
 		mb, ok := enh.signatureToMetricWithBuckets[l]
 		if !ok {
 			el.Metric = labels.NewBuilder(el.Metric).
-				Del(labels.BucketLabel, labels.MetricName).
+				Del(excludedLabels...).
 				Labels()
 
 			mb = &metricWithBuckets{el.Metric, nil}

promql/testdata/histograms.test

@@ -219,3 +219,12 @@ load 5m
 
 eval instant at 50m histogram_quantile(0.2, rate(empty_bucket[5m]))
 	{instance="ins1", job="job1"} NaN
+
+# Load a duplicate histogram with a different name to test failure scenario on multiple histograms with the same label set
+# https://github.com/prometheus/prometheus/issues/9910
+load 5m
+	request_duration_seconds2_bucket{job="job1", instance="ins1", le="0.1"}	0+1x10
+	request_duration_seconds2_bucket{job="job1", instance="ins1", le="0.2"}	0+3x10
+	request_duration_seconds2_bucket{job="job1", instance="ins1", le="+Inf"}	0+4x10
+
+eval_fail instant at 50m histogram_quantile(0.99, {__name__=~"request_duration.*"})