lib/prompb: properly reuse memory for native histogram parsing

Previously, bucket spans were incorrectly re-used due to missing `clear` call.
It could produce unexpected results with span bucket value from
previously parsed histogram.
 In addition, if timeseries had a multiple data values for the same
 histogram, metric name could add unexpected `bucket` prefix multiple
 times, producing `_bucket_bucket` metric names.

  This commit properly clears reused memory.

  Fixes https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11041

app/victoria-metrics/main.go

@@ -22,7 +22,6 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/procutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/pushmetrics"
-	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
 )
 
 var (
@@ -30,21 +29,11 @@ var (
 	useProxyProtocol = flagutil.NewArrayBool("httpListenAddr.useProxyProtocol", "Whether to use proxy protocol for connections accepted at the corresponding -httpListenAddr . "+
 		"See https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt . "+
 		"With enabled proxy protocol http server cannot serve regular /metrics endpoint. Use -pushmetrics.url for metrics pushing")
-	minScrapeInterval = flag.Duration("dedup.minScrapeInterval", 0, "Leave only the last sample in every time series per each discrete interval "+
-		"equal to -dedup.minScrapeInterval > 0. See also -streamAggr.dedupInterval and https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#deduplication")
 	dryRun = flag.Bool("dryRun", false, "Whether to check config files without running VictoriaMetrics. The following config files are checked: "+
 		"-promscrape.config, -relabelConfig and -streamAggr.config. Unknown config entries aren't allowed in -promscrape.config by default. "+
 		"This can be changed with -promscrape.config.strictParse=false command-line flag")
-	inmemoryDataFlushInterval = flag.Duration("inmemoryDataFlushInterval", 5*time.Second, "The interval for guaranteed saving of in-memory data to disk. "+
-		"The saved data survives unclean shutdowns such as OOM crash, hardware reset, SIGKILL, etc. "+
-		"Bigger intervals may help increase the lifetime of flash storage with limited write cycles (e.g. Raspberry PI). "+
-		"Smaller intervals increase disk IO load. Minimum supported value is 1s")
 	maxIngestionRate = flag.Int("maxIngestionRate", 0, "The maximum number of samples vmsingle can receive per second. Data ingestion is paused when the limit is exceeded. "+
 		"By default there are no limits on samples ingestion rate.")
-	finalDedupScheduleInterval = flag.Duration("storage.finalDedupScheduleCheckInterval", time.Hour, "The interval for checking when final deduplication process should be started."+
-		"Storage unconditionally adds 25% jitter to the interval value on each check evaluation."+
-		" Changing the interval to the bigger values may delay downsampling, deduplication for historical data."+
-		" See also https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#deduplication")
 )
 
 func main() {
@@ -87,12 +76,6 @@ func main() {
 	}
 	logger.Infof("starting VictoriaMetrics at %q...", listenAddrs)
 	startTime := time.Now()
-	storage.SetDedupInterval(*minScrapeInterval)
-	storage.SetDataFlushInterval(*inmemoryDataFlushInterval)
-	if *finalDedupScheduleInterval < time.Hour {
-		logger.Fatalf("-dedup.finalDedupScheduleCheckInterval cannot be smaller than 1 hour; got %s", *finalDedupScheduleInterval)
-	}
-	storage.SetFinalDedupScheduleInterval(*finalDedupScheduleInterval)
 	vmstorage.Init(promql.ResetRollupResultCacheIfNeeded)
 	vmselect.Init()
 	vminsertcommon.StartIngestionRateLimiter(*maxIngestionRate)

app/vmstorage/main.go

@@ -51,6 +51,12 @@ var (
 	retentionTimezoneOffset = flag.Duration("retentionTimezoneOffset", 0, "The offset for performing indexdb rotation. "+
 		"If set to 0, then the indexdb rotation is performed at 4am UTC time per each -retentionPeriod. "+
 		"If set to 2h, then the indexdb rotation is performed at 4am EET time (the timezone with +2h offset)")
+	minScrapeInterval = flag.Duration("dedup.minScrapeInterval", 0, "Leave only the last sample in every time series per each discrete interval "+
+		"equal to -dedup.minScrapeInterval > 0. See also -streamAggr.dedupInterval and https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#deduplication")
+	inmemoryDataFlushInterval = flag.Duration("inmemoryDataFlushInterval", 5*time.Second, "The interval for guaranteed saving of in-memory data to disk. "+
+		"The saved data survives unclean shutdowns such as OOM crash, hardware reset, SIGKILL, etc. "+
+		"Bigger intervals may help increase the lifetime of flash storage with limited write cycles (e.g. Raspberry PI). "+
+		"Smaller intervals increase disk IO load. Minimum supported value is 1s")
 
 	logNewSeries = flag.Bool("logNewSeries", false, "Whether to log new series. This option is for debug purposes only. It can lead to performance issues "+
 		"when big number of new series are ingested into VictoriaMetrics")
@@ -68,6 +74,11 @@ var (
 
 	minFreeDiskSpaceBytes = flagutil.NewBytes("storage.minFreeDiskSpaceBytes", 100e6, "The minimum free disk space at -storageDataPath after which the storage stops accepting new data")
 
+	finalDedupScheduleInterval = flag.Duration("storage.finalDedupScheduleCheckInterval", time.Hour, "The interval for checking when final deduplication process should be started."+
+		"Storage unconditionally adds 25% jitter to the interval value on each check evaluation."+
+		" Changing the interval to the bigger values may delay downsampling, deduplication for historical data."+
+		" See also https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#deduplication")
+
 	cacheSizeStorageTSID = flagutil.NewBytes("storage.cacheSizeStorageTSID", 0, "Overrides max size for storage/tsid cache. "+
 		"See https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#cache-tuning")
 	cacheSizeStorageMetricName = flagutil.NewBytes("storage.cacheSizeStorageMetricName", 0, "Overrides max size for storage/metricName cache. "+
@@ -111,11 +122,16 @@ func Init(resetCacheIfNeeded func(mrs []storage.MetricRow)) {
 		logger.Fatalf("invalid `-precisionBits`: %s", err)
 	}
 
-	resetResponseCacheIfNeeded = resetCacheIfNeeded
+	storage.SetDedupInterval(*minScrapeInterval)
+	storage.SetDataFlushInterval(*inmemoryDataFlushInterval)
 	storage.LegacySetRetentionTimezoneOffset(*retentionTimezoneOffset)
 	storage.SetFreeDiskSpaceLimit(minFreeDiskSpaceBytes.N)
 	storage.SetTSIDCacheSize(cacheSizeStorageTSID.IntN())
 	storage.SetTagFiltersCacheSize(cacheSizeIndexDBTagFilters.IntN())
+	if *finalDedupScheduleInterval < time.Hour {
+		logger.Fatalf("-storage.finalDedupScheduleCheckInterval cannot be smaller than 1 hour; got %s", *finalDedupScheduleInterval)
+	}
+	storage.SetFinalDedupScheduleInterval(*finalDedupScheduleInterval)
 	storage.SetMetricNamesStatsCacheSize(cacheSizeMetricNamesStats.IntN())
 	storage.SetMetricNameCacheSize(cacheSizeStorageMetricName.IntN())
 	storage.SetMetadataStorageSize(metadataStorageSize.IntN())
@@ -134,9 +150,9 @@ func Init(resetCacheIfNeeded func(mrs []storage.MetricRow)) {
 	if *idbPrefillStart > 23*time.Hour {
 		logger.Panicf("-storage.idbPrefillStart cannot exceed 23 hours; got %s", idbPrefillStart)
 	}
+	fs.RegisterPathFsMetrics(*storageDataPath)
 	logger.Infof("opening storage at %q with -retentionPeriod=%s", *storageDataPath, retentionPeriod)
 	startTime := time.Now()
-	WG = syncwg.WaitGroup{}
 	opts := storage.OpenOptions{
 		Retention:                   retentionPeriod.Duration(),
 		FutureRetention:             futureRetention.Duration(),
@@ -149,7 +165,6 @@ func Init(resetCacheIfNeeded func(mrs []storage.MetricRow)) {
 		LogNewSeries:                *logNewSeries,
 	}
 	strg := storage.MustOpenStorage(*storageDataPath, opts)
-	Storage = strg
 	initStaleSnapshotsRemover(strg)
 
 	var m storage.Metrics
@@ -168,7 +183,10 @@ func Init(resetCacheIfNeeded func(mrs []storage.MetricRow)) {
 		writeStorageMetrics(w, strg)
 	})
 	metrics.RegisterSet(storageMetrics)
-	fs.RegisterPathFsMetrics(*storageDataPath)
+
+	WG = syncwg.WaitGroup{}
+	resetResponseCacheIfNeeded = resetCacheIfNeeded
+	Storage = strg
 }
 
 var storageMetrics *metrics.Set
@@ -340,6 +358,7 @@ func RequestHandler(w http.ResponseWriter, r *http.Request) bool {
 			startTime := time.Now()
 			if err := Storage.ForceMergePartitions(partitionNamePrefix); err != nil {
 				logger.Errorf("error in forced merge for partition_prefix=%q: %s", partitionNamePrefix, err)
+				return
 			}
 			logger.Infof("forced merge for partition_prefix=%q has been successfully finished in %.3f seconds", partitionNamePrefix, time.Since(startTime).Seconds())
 		}()
@@ -353,6 +372,7 @@ func RequestHandler(w http.ResponseWriter, r *http.Request) bool {
 		Storage.DebugFlush()
 		return true
 	}
+
 	if path == "/internal/log_new_series" {
 		if !httpserver.CheckAuthFlag(w, r, logNewSeriesAuthKey) {
 			return true

docs/playgrounds/README.md

@@ -150,12 +150,12 @@ You can experiment with your own data during the month‑long trial without depl
 are fast-booting Linux microVMs that run on a fleet of large bare-metal servers. You can start a playground right from your browser. 
 Once up and running, accessing a playground is no different from SSH-ing into a remote server rented from your favorite VPS or Cloud provider.
 
-Iximiuz Labs provides various [learning-by-doing resources for VictoriaMetrics](https://labs.iximiuz.com/v/victoriametrics-bb1fdaa1):
+Iximiuz Labs provides various [learning-by-doing resources for VictoriaMetrics](https://labs.iximiuz.com/v/victoriametrics):
 - Tutorial:
-  - [Getting Started with VictoriaMetrics on Kubernetes](https://labs.iximiuz.com/tutorials/victoriametrics-getting-started-kubernetes-0e9c0993)
+  - [Getting Started with VictoriaMetrics on Kubernetes](https://labs.iximiuz.com/tutorials/victoriametrics-getting-started-kubernetes)
 - Playgrounds:
-  - [VictoriaMetrics single node](https://labs.iximiuz.com/playgrounds/victoriametrics-e2f9b613)
-  - [VictoriaMetrics cluster](https://labs.iximiuz.com/playgrounds/victoriametrics-cluster-8eacb19d)
-  - [VictoriaMetrics on Kubernetes](https://labs.iximiuz.com/playgrounds/victoriametrics-kubernetes-9eebc258)
+  - [VictoriaMetrics single node](https://labs.iximiuz.com/playgrounds/victoriametrics)
+  - [VictoriaMetrics cluster](https://labs.iximiuz.com/playgrounds/victoriametrics-cluster)
+  - [VictoriaMetrics on Kubernetes](https://labs.iximiuz.com/playgrounds/victoriametrics-kubernetes)
 
 Iximiuz Labs requires a [free account](https://labs.iximiuz.com/signup) to access the materials.

docs/victoriametrics/changelog/CHANGELOG.md

@@ -28,6 +28,8 @@ See also [LTS releases](https://docs.victoriametrics.com/victoriametrics/lts-rel
 
 * FEATURE: [vmagent](https://docs.victoriametrics.com/victoriametrics/vmagent/), [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/) and `vminsert` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): add `-opentelemetry.promoteAllResourceAttributes` and `-opentelemetry.promoteScopeMetadata` command-line flags to allow managing label promotion for resource attributes and OTel scope metadata. See [OpenTelemetry](https://docs.victoriametrics.com/victoriametrics/integrations/opentelemetry/) docs and [#10931](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/10931).
 
+* BUGFIX:  [vmagent](https://docs.victoriametrics.com/victoriametrics/vmagent/) and [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/): properly parse [Prometheus native histogram](https://prometheus.io/docs/specs/native_histograms/), previously it could produce unexpected `vmrange` labels. See [#11041](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11041).
+
 ## [v1.144.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.144.0)
 
 Released at 2026-05-22

lib/prompb/write_request_unmarshaler.go

@@ -398,6 +398,10 @@ func (nhctx *nativeHistogramContext) appendTimeSeries(tss []TimeSeries, baseLabe
 	if baseName == "" {
 		return tss, labelsPool, samplesPool
 	}
+	originName := *nameValueP
+	defer func() {
+		*nameValueP = originName
+	}()
 
 	*nameValueP = fb.formatName(baseName, "_count")
 	tss, labelsPool, samplesPool = appendHistogramSeries(tss, labelsPool, samplesPool, baseLabels, "", tsMillis, count)
@@ -550,9 +554,11 @@ func (nhctx *nativeHistogramContext) reset() {
 	nhctx.zeroCountInt = 0
 	nhctx.zeroCountFloat = 0
 	nhctx.timestamp = 0
+	clear(nhctx.negativeSpans)
 	nhctx.negativeSpans = nhctx.negativeSpans[:0]
 	nhctx.negativeDeltas = nhctx.negativeDeltas[:0]
 	nhctx.negativeCounts = nhctx.negativeCounts[:0]
+	clear(nhctx.positiveSpans)
 	nhctx.positiveSpans = nhctx.positiveSpans[:0]
 	nhctx.positiveDeltas = nhctx.positiveDeltas[:0]
 	nhctx.positiveCounts = nhctx.positiveCounts[:0]

lib/prompb/write_request_unmarshaler_test.go

@@ -3,8 +3,9 @@ package prompb
 import (
 	"encoding/binary"
 	"math"
-	"reflect"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestUnmarshalTimeSeries(t *testing.T) {
@@ -18,8 +19,8 @@ func TestUnmarshalTimeSeries(t *testing.T) {
 		if err != nil {
 			t.Fatalf("unexpected error: %s", err)
 		}
-		if !reflect.DeepEqual(tss, wantTSS) {
-			t.Fatalf("unexpected result\ngot:\n%v\nwant:\n%v", tss, wantTSS)
+		if diff := cmp.Diff(wantTSS, tss); len(diff) > 0 {
+			t.Fatalf("unexpected timeseries (-want, +got):\n%s", diff)
 		}
 	}
 
@@ -197,6 +198,93 @@ func TestUnmarshalTimeSeries(t *testing.T) {
 			},
 		})
 	}
+
+	{
+		// verify histogram fields are correctly reused
+		nativeHistogramC := nativeHistogramContext{
+			countInt:         0,
+			isCountFloat:     true,
+			countFloat:       2.5,
+			sum:              1.0,
+			schema:           1,
+			zeroThreshold:    0.00001,
+			isZeroCountFloat: true,
+			zeroCountFloat:   0.5,
+			timestamp:        3000,
+			positiveSpans:    []bucketSpan{{offset: 1, length: 2}},
+			positiveCounts:   []float64{1.5, 1.0},
+			negativeSpans:    []bucketSpan{{offset: 0, length: 1}},
+		}
+		nativeHistogramC2 := nativeHistogramContext{
+			countInt:         0,
+			isCountFloat:     true,
+			countFloat:       0,
+			sum:              1.0,
+			schema:           1,
+			zeroThreshold:    0.00001,
+			isZeroCountFloat: true,
+			zeroCountFloat:   0.5,
+			timestamp:        4000,
+			positiveSpans:    []bucketSpan{{offset: 0, length: 2}},
+			positiveCounts:   []float64{1.5, 1.0},
+			negativeSpans:    []bucketSpan{{offset: 0, length: 1}},
+			negativeCounts:   []float64{1.5, 0},
+		}
+		hd1 := encodeHistogram(nativeHistogramC)
+		hd2 := encodeHistogram(nativeHistogramC2)
+
+		src := encodeTimeSeries(
+			[]Label{{Name: "__name__", Value: "rpc_latency_seconds"}},
+			nil,
+			[][]byte{hd1, hd2},
+		)
+		f(src, []TimeSeries{
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_count"}},
+				Samples: []Sample{{Value: 2.5, Timestamp: 3000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_sum"}},
+				Samples: []Sample{{Value: 1.0, Timestamp: 3000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_bucket"}, {Name: "vmrange", Value: appendVmrangeHelper(-0.00001, 0.00001)}},
+				Samples: []Sample{{Value: 0.5, Timestamp: 3000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_bucket"}, {Name: "vmrange", Value: appendVmrangeHelper(1, 1.414)}},
+				Samples: []Sample{{Value: 1.5, Timestamp: 3000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_bucket"}, {Name: "vmrange", Value: appendVmrangeHelper(1.414, 2.0)}},
+				Samples: []Sample{{Value: 1.0, Timestamp: 3000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_count"}},
+				Samples: []Sample{{Value: 0, Timestamp: 4000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_sum"}},
+				Samples: []Sample{{Value: 1.0, Timestamp: 4000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_bucket"}, {Name: "vmrange", Value: appendVmrangeHelper(-0.00001, 0.00001)}},
+				Samples: []Sample{{Value: 0.5, Timestamp: 4000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_bucket"}, {Name: "vmrange", Value: appendVmrangeHelper(0.7071, 1)}},
+				Samples: []Sample{{Value: 1.5, Timestamp: 4000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_bucket"}, {Name: "vmrange", Value: appendVmrangeHelper(1, 1.414)}},
+				Samples: []Sample{{Value: 1.0, Timestamp: 4000}},
+			},
+			{
+				Labels:  []Label{{Name: "__name__", Value: "rpc_latency_seconds_bucket"}, {Name: "vmrange", Value: appendVmrangeHelper(-1, -0.7071)}},
+				Samples: []Sample{{Value: 1.5, Timestamp: 4000}},
+			},
+		})
+	}
 }
 
 func encodeTimeSeries(labels []Label, samples []Sample, histograms [][]byte) []byte {