MQE: fix rate() over native histograms where first point in range i…

…s a counter reset (#9371)

* MQE: fix `rate()` over native histograms where first point is a counter reset

* Add changelog entry

(cherry picked from commit 20a3c74)

CHANGELOG.md

@@ -33,7 +33,7 @@
 * [CHANGE] Query-scheduler: Remove the experimental `-query-scheduler.use-multi-algorithm-query-queue` flag. The new multi-algorithm tree queue is always used for the scheduler. #9210
 * [FEATURE] Alertmanager: Added `-alertmanager.log-parsing-label-matchers` to control logging when parsing label matchers. This flag is intended to be used with `-alertmanager.utf8-strict-mode-enabled` to validate UTF-8 strict mode is working as intended. The default value is `false`. #9173
 * [FEATURE] Alertmanager: Added `-alertmanager.utf8-migration-logging-enabled` to enable logging of tenant configurations that are incompatible with UTF-8 strict mode. The default value is `false`. #9174
-* [FEATURE] Querier: add experimental streaming PromQL engine, enabled with `-querier.query-engine=mimir`. #8422 #8430 #8454 #8455 #8360 #8490 #8508 #8577 #8660 #8671 #8677 #8747 #8850 #8872 #8838 #8911 #8909 #8923 #8924 #8925 #8932 #8933 #8934 #8962 #8986 #8993 #8995 #9008 #9017 #9018 #9019 #9120 #9121 #9136 #9139 #9140 #9145 #9191 #9192 #9194 #9196 #9201 #9212 #9225 #9260 #9272 #9277 #9278 #9280
+* [FEATURE] Querier: add experimental streaming PromQL engine, enabled with `-querier.query-engine=mimir`. #8422 #8430 #8454 #8455 #8360 #8490 #8508 #8577 #8660 #8671 #8677 #8747 #8850 #8872 #8838 #8911 #8909 #8923 #8924 #8925 #8932 #8933 #8934 #8962 #8986 #8993 #8995 #9008 #9017 #9018 #9019 #9120 #9121 #9136 #9139 #9140 #9145 #9191 #9192 #9194 #9196 #9201 #9212 #9225 #9260 #9272 #9277 #9278 #9280 #9371
 * [FEATURE] Experimental Kafka-based ingest storage. #6888 #6894 #6929 #6940 #6951 #6974 #6982 #7029 #7030 #7091 #7142 #7147 #7148 #7153 #7160 #7193 #7349 #7376 #7388 #7391 #7393 #7394 #7402 #7404 #7423 #7424 #7437 #7486 #7503 #7508 #7540 #7621 #7682 #7685 #7694 #7695 #7696 #7697 #7701 #7733 #7734 #7741 #7752 #7838 #7851 #7871 #7877 #7880 #7882 #7887 #7891 #7925 #7955 #7967 #8031 #8063 #8077 #8088 #8135 #8176 #8184 #8194 #8216 #8217 #8222 #8233 #8503 #8542 #8579 #8657 #8686 #8688 #8703 #8706 #8708 #8738 #8750 #8778 #8808 #8809 #8841 #8842 #8845 #8853 #8886 #8988
   * What it is:
     * When the new ingest storage architecture is enabled, distributors write incoming write requests to a Kafka-compatible backend, and the ingesters asynchronously replay ingested data from Kafka. In this architecture, the write and read path are de-coupled through a Kafka-compatible backend. The write path and Kafka load is a function of the incoming write traffic, the read path load is a function of received queries. Whatever the load on the read path, it doesn't affect the write path.

pkg/streamingpromql/functions/rate.go

@@ -42,7 +42,7 @@ func rate(step types.RangeVectorStepData, rangeSeconds float64, floatBuffer *typ
 	}
 
 	if hCount >= 2 {
-		val, err := histogramRate(histogramBuffer, step, hHead, hTail, rangeSeconds, hCount, emitAnnotation)
+		val, err := histogramRate(step, hHead, hTail, rangeSeconds, hCount, emitAnnotation)
 		if err != nil {
 			err = NativeHistogramErrorToAnnotation(err, emitAnnotation)
 			return 0, false, nil, err
@@ -53,9 +53,15 @@ func rate(step types.RangeVectorStepData, rangeSeconds float64, floatBuffer *typ
 	return 0, false, nil, nil
 }
 
-func histogramRate(histogramBuffer *types.HPointRingBuffer, step types.RangeVectorStepData, hHead []promql.HPoint, hTail []promql.HPoint, rangeSeconds float64, hCount int, emitAnnotation EmitAnnotationFunc) (*histogram.FloatHistogram, error) {
-	firstPoint := histogramBuffer.First()
-	usingCustomBuckets := firstPoint.H.UsesCustomBuckets()
+func histogramRate(step types.RangeVectorStepData, hHead []promql.HPoint, hTail []promql.HPoint, rangeSeconds float64, hCount int, emitAnnotation EmitAnnotationFunc) (*histogram.FloatHistogram, error) {
+	var firstPoint promql.HPoint
+	if len(hHead) > 0 {
+		firstPoint = hHead[0]
+		hHead = hHead[1:]
+	} else {
+		firstPoint = hTail[0]
+		hTail = hTail[1:]
+	}
 
 	var lastPoint promql.HPoint
 	if len(hTail) > 0 {
@@ -73,6 +79,7 @@ func histogramRate(histogramBuffer *types.HPointRingBuffer, step types.RangeVect
 		currentSchema = lastPoint.H.Schema
 	}
 
+	usingCustomBuckets := firstPoint.H.UsesCustomBuckets()
 	if lastPoint.H.UsesCustomBuckets() != usingCustomBuckets {
 		return nil, histogram.ErrHistogramsIncompatibleSchema
 	}

pkg/streamingpromql/testdata/ours/native_histograms.test

@@ -147,6 +147,15 @@ eval range from 0 to 4m step 1m sum by (env) (rate(incr_histogram[5m]))
 
 clear
 
+# Test rate() with explicit counter reset information.
+load 1m
+  metric {{sum:3 count:4 buckets:[1 2 1] counter_reset_hint:reset}} {{sum:63 count:124 buckets:[100 4 20] counter_reset_hint:not_reset}}
+
+eval instant at 1m rate(metric[1m])
+  {} {{sum:1 count:2 buckets:[1.65 0.03333333333333333 0.31666666666666665] counter_reset_hint:gauge}}
+
+clear
+
 # Test mixing exponential and custom buckets.
 load 6m
   metric{series="exponential"}         {{sum:4 count:5 buckets:[1 3 1]}}  _                                                                 {{sum:4 count:5 buckets:[1 3 1]}}                                 {{sum:4 count:5 buckets:[1 3 1]}}  _