Merge pull request #15527 from NeerajGartia21/promql/funcResets

[BUGFIX] PromQL: Fix `resets` function for histograms

promql/functions.go

@@ -1400,27 +1400,41 @@ func funcResets(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelpe
 	floats := vals[0].(Matrix)[0].Floats
 	histograms := vals[0].(Matrix)[0].Histograms
 	resets := 0
-
-	if len(floats) > 1 {
-		prev := floats[0].F
-		for _, sample := range floats[1:] {
-			current := sample.F
-			if current < prev {
-				resets++
-			}
-			prev = current
-		}
+	if len(floats) == 0 && len(histograms) == 0 {
+		return enh.Out, nil
 	}
 
-	if len(histograms) > 1 {
-		prev := histograms[0].H
-		for _, sample := range histograms[1:] {
-			current := sample.H
-			if current.DetectReset(prev) {
+	var prevSample, curSample Sample
+	for iFloat, iHistogram := 0, 0; iFloat < len(floats) || iHistogram < len(histograms); {
+		switch {
+		// Process a float sample if no histogram sample remains or its timestamp is earlier.
+		// Process a histogram sample if no float sample remains or its timestamp is earlier.
+		case iHistogram >= len(histograms) || iFloat < len(floats) && floats[iFloat].T < histograms[iHistogram].T:
+			curSample.F = floats[iFloat].F
+			curSample.H = nil
+			iFloat++
+		case iFloat >= len(floats) || iHistogram < len(histograms) && floats[iFloat].T > histograms[iHistogram].T:
+			curSample.H = histograms[iHistogram].H
+			iHistogram++
+		}
+		// Skip the comparison for the first sample, just initialize prevSample.
+		if iFloat+iHistogram == 1 {
+			prevSample = curSample
+			continue
+		}
+		switch {
+		case prevSample.H == nil && curSample.H == nil:
+			if curSample.F < prevSample.F {
+				resets++
+			}
+		case prevSample.H != nil && curSample.H == nil, prevSample.H == nil && curSample.H != nil:
+			resets++
+		case prevSample.H != nil && curSample.H != nil:
+			if curSample.H.DetectReset(prevSample.H) {
 				resets++
 			}
-			prev = current
 		}
+		prevSample = curSample
 	}
 
 	return append(enh.Out, Sample{F: float64(resets)}), nil
@@ -1441,16 +1455,12 @@ func funcChanges(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelp
 		// Process a float sample if no histogram sample remains or its timestamp is earlier.
 		// Process a histogram sample if no float sample remains or its timestamp is earlier.
 		case iHistogram >= len(histograms) || iFloat < len(floats) && floats[iFloat].T < histograms[iHistogram].T:
-			{
-				curSample.F = floats[iFloat].F
-				curSample.H = nil
-				iFloat++
-			}
+			curSample.F = floats[iFloat].F
+			curSample.H = nil
+			iFloat++
 		case iFloat >= len(floats) || iHistogram < len(histograms) && floats[iFloat].T > histograms[iHistogram].T:
-			{
-				curSample.H = histograms[iHistogram].H
-				iHistogram++
-			}
+			curSample.H = histograms[iHistogram].H
+			iHistogram++
 		}
 		// Skip the comparison for the first sample, just initialize prevSample.
 		if iFloat+iHistogram == 1 {
@@ -1459,20 +1469,14 @@ func funcChanges(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelp
 		}
 		switch {
 		case prevSample.H == nil && curSample.H == nil:
-			{
-				if curSample.F != prevSample.F && !(math.IsNaN(curSample.F) && math.IsNaN(prevSample.F)) {
-					changes++
-				}
-			}
-		case prevSample.H != nil && curSample.H == nil, prevSample.H == nil && curSample.H != nil:
-			{
+			if curSample.F != prevSample.F && !(math.IsNaN(curSample.F) && math.IsNaN(prevSample.F)) {
 				changes++
 			}
+		case prevSample.H != nil && curSample.H == nil, prevSample.H == nil && curSample.H != nil:
+			changes++
 		case prevSample.H != nil && curSample.H != nil:
-			{
-				if !curSample.H.Equals(prevSample.H) {
-					changes++
-				}
+			if !curSample.H.Equals(prevSample.H) {
+				changes++
 			}
 		}
 		prevSample = curSample

promql/promqltest/testdata/functions.test

@@ -5,7 +5,7 @@ load 5m
 	http_requests{path="/biz"}  0 0 0 0 0 1 1 1 1 1
     http_requests_histogram{path="/foo"}    {{schema:0 sum:1 count:1}}x9
     http_requests_histogram{path="/bar"}    0 0 0 0 0 0 0 0 {{schema:0 sum:1 count:1}} {{schema:0 sum:1 count:1}}
-    http_requests_histogram{path="/biz"}    0 1 0 2 0 3 0 {{schema:0 sum:1 count:1}} {{schema:0 sum:2 count:2}} {{schema:0 sum:1 count:1}}
+    http_requests_histogram{path="/biz"}    0 1 0 2 0 3 0 {{schema:0 sum:1 count:1 z_bucket_w:0.001 z_bucket:2}} {{schema:0 sum:2 count:2 z_bucket_w:0.001 z_bucket:1}} {{schema:0 sum:1 count:1 z_bucket_w:0.001 z_bucket:2}}
 
 # Tests for resets().
 eval instant at 50m resets(http_requests[5m])
@@ -42,6 +42,18 @@ eval instant at 50m resets(http_requests[50m])
 
 eval instant at 50m resets(nonexistent_metric[50m])
 
+# Test for mix of floats and histograms.
+
+eval instant at 50m resets(http_requests_histogram[6m])
+    {path="/foo"} 0
+    {path="/bar"} 0
+    {path="/biz"} 0
+
+eval instant at 50m resets(http_requests_histogram[60m])
+    {path="/foo"} 0
+    {path="/bar"} 1
+    {path="/biz"} 6
+
 # Tests for changes().
 eval instant at 50m changes(http_requests[5m])