update changelog

Signed-off-by: Artem Fetishev <rtm@victoriametrics.com>

.github/workflows/codeql-analysis-go.yml

@@ -52,14 +52,14 @@ jobs:
           restore-keys: go-artifacts-${{ runner.os }}-codeql-analyze-${{ steps.go.outputs.go-version }}-
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@7211b7c8077ea37d8641b6271f6a365a22a5fbfa  # v4.36.0
+        uses: github/codeql-action/init@e46ed2cbd01164d986452f91f178727624ae40d7  # v4.35.3
         with:
           languages: go
 
       - name: Autobuild
-        uses: github/codeql-action/autobuild@7211b7c8077ea37d8641b6271f6a365a22a5fbfa  # v4.36.0
+        uses: github/codeql-action/autobuild@e46ed2cbd01164d986452f91f178727624ae40d7  # v4.35.3
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@7211b7c8077ea37d8641b6271f6a365a22a5fbfa  # v4.36.0
+        uses: github/codeql-action/analyze@e46ed2cbd01164d986452f91f178727624ae40d7  # v4.35.3
         with:
           category: 'language:go'

Makefile

@@ -471,8 +471,9 @@ test-full-386:
 
 apptest:
 	$(MAKE) victoria-metrics-race vmagent-race vmalert-race vmauth-race vmctl-race vmbackup-race vmrestore-race
-	go test ./apptest/... -skip="^Test(Cluster|Legacy).*"
+	go test ./apptest/... -skip="^Test(Cluster|Mixed|Legacy).*"
 
+# App tests for legacy indexDB
 apptest-legacy: victoria-metrics-race vmbackup-race vmrestore-race
 	OS=$$(uname | tr '[:upper:]' '[:lower:]'); \
 	ARCH=$$(uname -m | tr '[:upper:]' '[:lower:]' | sed 's/x86_64/amd64/'); \
@@ -489,6 +490,20 @@ apptest-legacy: victoria-metrics-race vmbackup-race vmrestore-race
 	VMSTORAGE_V1_132_0_PATH=$${DIR}/vmstorage-prod \
 	go test ./apptest/tests -run="^TestLegacySingle.*"
 
+# App tests for mixed setups where vmsingle and vmcluster coexist.
+apptest-mixed: victoria-metrics-race
+	OS=$$(uname | tr '[:upper:]' '[:lower:]'); \
+	ARCH=$$(uname -m | tr '[:upper:]' '[:lower:]' | sed 's/x86_64/amd64/'); \
+	VERSION=v1.145.0; \
+	VMCLUSTER=victoria-metrics-$${OS}-$${ARCH}-$${VERSION}-cluster.tar.gz; \
+	URL=https://github.com/VictoriaMetrics/VictoriaMetrics/releases/download/$${VERSION}; \
+	DIR=/tmp/$${VERSION}; \
+	test -d $${DIR} || (mkdir $${DIR} && \
+		curl --output-dir /tmp -LO $${URL}/$${VMCLUSTER} && tar xzf /tmp/$${VMCLUSTER} -C $${DIR} \
+	); \
+	VMSELECT_PATH=$${DIR}/vmselect-prod \
+	go test ./apptest/tests -run="^TestMixed.*"
+
 benchmark:
 	go test -run=NO_TESTS -bench=. ./lib/...
 	go test -run=NO_TESTS -bench=. ./app/...

app/victoria-metrics/main.go

@@ -89,7 +89,7 @@ func main() {
 	}
 	logger.Infof("starting VictoriaMetrics at %q...", listenAddrs)
 	startTime := time.Now()
-	vmstorage.Init(*vmselectMaxConcurrentRequests, promql.ResetRollupResultCacheIfNeeded)
+	vmstorage.Init(*vmselectMaxConcurrentRequests, *vmselectMaxQueueDuration, promql.ResetRollupResultCacheIfNeeded)
 	vmselect.Init(*vmselectMaxConcurrentRequests, *vmselectMaxQueueDuration)
 	vminsertcommon.StartIngestionRateLimiter(*maxIngestionRate)
 	vminsert.Init()

app/vmalert-tool/unittest/unittest.go

@@ -282,7 +282,8 @@ func processFlags() {
 
 func setUp() {
 	const maxConcurrentRequests = 4
-	vmstorage.Init(maxConcurrentRequests, promql.ResetRollupResultCacheIfNeeded)
+	maxQueueDuration := 5 * time.Second
+	vmstorage.Init(maxConcurrentRequests, maxQueueDuration, promql.ResetRollupResultCacheIfNeeded)
 	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 	defer cancel()
 	readyCheckFunc := func() bool {

app/vmctl/auth/auth.go

@@ -131,16 +131,13 @@ func (ac *authContext) initFromBasicAuthConfig(ba *BasicAuthConfig) error {
 	if ba.Username == "" {
 		return fmt.Errorf("missing `username` in `basic_auth` section")
 	}
-	if ba.Password != "" {
-		ac.getAuthHeader = func() string {
-			// See https://en.wikipedia.org/wiki/Basic_access_authentication
-			token := ba.Username + ":" + ba.Password
-			token64 := base64.StdEncoding.EncodeToString([]byte(token))
-			return "Basic " + token64
-		}
-		ac.authDigest = fmt.Sprintf("basic(username=%q, password=%q)", ba.Username, ba.Password)
-		return nil
+	ac.getAuthHeader = func() string {
+		// See https://en.wikipedia.org/wiki/Basic_access_authentication
+		token := ba.Username + ":" + ba.Password
+		token64 := base64.StdEncoding.EncodeToString([]byte(token))
+		return "Basic " + token64
 	}
+	ac.authDigest = fmt.Sprintf("basic(username=%q, password=%q)", ba.Username, ba.Password)
 	return nil
 }
 

app/vmctl/flags.go

@@ -69,6 +69,8 @@ const (
 	vmAddr               = "vm-addr"
 	vmUser               = "vm-user"
 	vmPassword           = "vm-password"
+	vmHeaders            = "vm-headers"
+	vmBearerToken        = "vm-bearer-token"
 	vmAccountID          = "vm-account-id"
 	vmConcurrency        = "vm-concurrency"
 	vmCompress           = "vm-compress"
@@ -112,6 +114,16 @@ var (
 			Usage:   "VictoriaMetrics password for basic auth",
 			EnvVars: []string{"VM_PASSWORD"},
 		},
+		&cli.StringFlag{
+			Name: vmHeaders,
+			Usage: "Optional HTTP headers to send with each request to the corresponding destination address. \n" +
+				"For example, --vm-headers='My-Auth:foobar' would send 'My-Auth: foobar' HTTP header with every request to the corresponding destination address. \n" +
+				"Multiple headers must be delimited by '^^': --vm-headers='header1:value1^^header2:value2'",
+		},
+		&cli.StringFlag{
+			Name:  vmBearerToken,
+			Usage: "Optional bearer auth token to use for the corresponding --vm-addr",
+		},
 		&cli.StringFlag{
 			Name: vmAccountID,
 			Usage: "AccountID is an arbitrary 32-bit integer identifying namespace for data ingestion (aka tenant). \n" +

app/vmctl/main.go

@@ -457,7 +457,7 @@ func main() {
 						auth.WithBearer(c.String(vmNativeDstBearerToken)),
 						auth.WithHeaders(c.String(vmNativeDstHeaders)))
 					if err != nil {
-						return fmt.Errorf("error initialize auth config for destination: %s", dstAddr)
+						return fmt.Errorf("error initialize auth config for destination: %s: %s", dstAddr, err)
 					}
 
 					// create TLS config
@@ -596,11 +596,18 @@ func initConfigVM(c *cli.Context) (vm.Config, error) {
 		return vm.Config{}, fmt.Errorf("failed to create backoff object: %w", err)
 	}
 
+	authCfg, err := auth.Generate(
+		auth.WithBasicAuth(c.String(vmUser), c.String(vmPassword)),
+		auth.WithBearer(c.String(vmBearerToken)),
+		auth.WithHeaders(c.String(vmHeaders)))
+	if err != nil {
+		return vm.Config{}, fmt.Errorf("error initialize auth config for destination: %s: %s", addr, err)
+	}
+
 	return vm.Config{
 		Addr:               addr,
 		Transport:          tr,
-		User:               c.String(vmUser),
-		Password:           c.String(vmPassword),
+		AuthCfg:            authCfg,
 		Concurrency:        uint8(c.Int(vmConcurrency)),
 		Compress:           c.Bool(vmCompress),
 		AccountID:          c.String(vmAccountID),

app/vmctl/vm/vm.go

@@ -12,6 +12,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmctl/auth"
 	"github.com/VictoriaMetrics/metrics"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmctl/backoff"
@@ -27,6 +28,8 @@ type Config struct {
 	//   --httpListenAddr value for single node version
 	//   --httpListenAddr value of vmselect  component for cluster version
 	Addr string
+
+	AuthCfg *auth.Config
 	// Transport allows specifying custom http.Transport
 	Transport *http.Transport
 	// Concurrency defines number of worker
@@ -40,10 +43,6 @@ type Config struct {
 	// BatchSize defines how many samples
 	// importer collects before sending the import request
 	BatchSize int
-	// User name for basic auth
-	User string
-	// Password for basic auth
-	Password string
 	// SignificantFigures defines the number of significant figures to leave
 	// in metric values before importing.
 	// Zero value saves all the significant decimal places
@@ -65,11 +64,10 @@ type Config struct {
 // see https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#how-to-import-time-series-data
 type Importer struct {
 	addr       string
+	authCfg    *auth.Config
 	client     *http.Client
 	importPath string
 	compress   bool
-	user       string
-	password   string
 
 	close  chan struct{}
 	input  chan *TimeSeries
@@ -148,8 +146,7 @@ func NewImporter(ctx context.Context, cfg Config) (*Importer, error) {
 		client:     client,
 		importPath: importPath,
 		compress:   cfg.Compress,
-		user:       cfg.User,
-		password:   cfg.Password,
+		authCfg:    cfg.AuthCfg,
 		rl:         limiter.NewLimiter(cfg.RateLimit),
 		close:      make(chan struct{}),
 		input:      make(chan *TimeSeries, cfg.Concurrency*4),
@@ -304,8 +301,8 @@ func (im *Importer) Ping() error {
 	if err != nil {
 		return fmt.Errorf("cannot create request to %q: %w", im.addr, err)
 	}
-	if im.user != "" {
-		req.SetBasicAuth(im.user, im.password)
+	if im.authCfg != nil {
+		im.authCfg.SetHeaders(req, true)
 	}
 	resp, err := im.client.Do(req)
 	if err != nil {
@@ -334,8 +331,8 @@ func (im *Importer) Import(tsBatch []*TimeSeries) error {
 		im.importRequestsErrorsTotal.Inc()
 		return fmt.Errorf("cannot create request to %q: %w", im.addr, err)
 	}
-	if im.user != "" {
-		req.SetBasicAuth(im.user, im.password)
+	if im.authCfg != nil {
+		im.authCfg.SetHeaders(req, true)
 	}
 	if im.compress {
 		req.Header.Set("Content-Encoding", "gzip")

app/vmselect/main.go

@@ -6,8 +6,6 @@ import (
 	"flag"
 	"fmt"
 	"net/http"
-	nethttputil "net/http/httputil"
-	"net/url"
 	"strings"
 	"time"
 
@@ -29,6 +27,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/vmalertproxy"
 )
 
 var (
@@ -38,7 +37,10 @@ var (
 	resetCacheAuthKey    = flagutil.NewPassword("search.resetCacheAuthKey", "Optional authKey for resetting rollup cache via /internal/resetRollupResultCache call. It could be passed via authKey query arg. It overrides -httpAuth.*")
 	logSlowQueryDuration = flag.Duration("search.logSlowQueryDuration", 5*time.Second, "Log queries with execution time exceeding this value. Zero disables slow query logging. "+
 		"See also -search.logQueryMemoryUsage")
-	vmalertProxyURL = flag.String("vmalert.proxyURL", "", "Optional URL for proxying requests to vmalert. For example, if -vmalert.proxyURL=http://vmalert:8880 , then alerting API requests such as /api/v1/rules from Grafana will be proxied to http://vmalert:8880/api/v1/rules")
+
+	vmalertProxyURL = flag.String("vmalert.proxyURL", "", "Optional URL for proxying requests to vmalert. For example, if -vmalert.proxyURL=http://vmalert:8880 , "+
+		"then alerting API requests such as /api/v1/rules from Grafana will be proxied to http://vmalert:8880/api/v1/rules . "+
+		"See https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#vmalert")
 )
 
 var slowQueries = metrics.NewCounter(`vm_slow_queries_total`)
@@ -55,8 +57,8 @@ func Init(vmselectMaxConcurrentRequests int, vmselectMaxQueueDuration time.Durat
 	concurrencyLimitCh = make(chan struct{}, maxConcurrentRequests)
 
 	initVMUIConfig()
-	initVMAlertProxy()
 
+	vmalertproxy.Init(*vmalertProxyURL)
 	flagutil.RegisterSecretFlag("vmalert.proxyURL")
 }
 
@@ -514,10 +516,11 @@ func handleStaticAndSimpleRequests(w http.ResponseWriter, r *http.Request, path
 		if len(*vmalertProxyURL) == 0 {
 			w.WriteHeader(http.StatusBadRequest)
 			w.Header().Set("Content-Type", "application/json")
-			fmt.Fprintf(w, "%s", `{"status":"error","msg":"for accessing vmalert flag '-vmalert.proxyURL' must be configured"}`)
+			fmt.Fprintf(w, "%s", `{"status":"error","msg":"the '-vmalert.proxyURL' command-line must be configured; `+
+				`see https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#vmalert"}`)
 			return true
 		}
-		proxyVMAlertRequests(w, r, path)
+		vmalertproxy.HandleRequest(w, r, path)
 		return true
 	}
 
@@ -555,7 +558,7 @@ func handleStaticAndSimpleRequests(w http.ResponseWriter, r *http.Request, path
 	case "/api/v1/rules", "/rules":
 		rulesRequests.Inc()
 		if len(*vmalertProxyURL) > 0 {
-			proxyVMAlertRequests(w, r, path)
+			vmalertproxy.HandleRequest(w, r, path)
 			return true
 		}
 		// Return dumb placeholder for https://prometheus.io/docs/prometheus/latest/querying/api/#rules
@@ -565,7 +568,7 @@ func handleStaticAndSimpleRequests(w http.ResponseWriter, r *http.Request, path
 	case "/api/v1/alerts", "/alerts":
 		alertsRequests.Inc()
 		if len(*vmalertProxyURL) > 0 {
-			proxyVMAlertRequests(w, r, path)
+			vmalertproxy.HandleRequest(w, r, path)
 			return true
 		}
 		// Return dumb placeholder for https://prometheus.io/docs/prometheus/latest/querying/api/#alerts
@@ -575,7 +578,7 @@ func handleStaticAndSimpleRequests(w http.ResponseWriter, r *http.Request, path
 	case "/api/v1/notifiers", "/notifiers":
 		notifiersRequests.Inc()
 		if len(*vmalertProxyURL) > 0 {
-			proxyVMAlertRequests(w, r, path)
+			vmalertproxy.HandleRequest(w, r, path)
 			return true
 		}
 		w.Header().Set("Content-Type", "application/json")
@@ -722,48 +725,7 @@ var (
 	metricNamesStatsResetErrors   = metrics.NewCounter(`vm_http_request_errors_total{path="/api/v1/admin/status/metric_names_stats/reset"}`)
 )
 
-func proxyVMAlertRequests(w http.ResponseWriter, r *http.Request, path string) {
-	defer func() {
-		err := recover()
-		if err == nil || err == http.ErrAbortHandler {
-			// Suppress http.ErrAbortHandler panic.
-			// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1353
-			return
-		}
-		// Forward other panics to the caller.
-		panic(err)
-	}()
-	req := r.Clone(r.Context())
-	req.URL.Path = strings.TrimPrefix(path, "prometheus")
-	req.Host = vmalertProxyHost
-
-	if strings.HasPrefix(r.Header.Get(`User-Agent`), `Grafana`) {
-		// Grafana currently supports only Prometheus-style alerts. If other alert types
-		// (e.g. logs or traces) are returned, it may fail with "Error loading alerts".
-		//
-		// Grafana queries the vmalert API directly, bypassing the VictoriaMetrics datasource,
-		// so query params (such as datasource_type) cannot be enforced on the Grafana side.
-		//
-		// To ensure compatibility, we detect Grafana requests via the User-Agent and enforce
-		// `datasource_type=prometheus`.
-		//
-		// See:
-		// - https://github.com/VictoriaMetrics/victoriametrics-datasource/issues/329#issuecomment-3847585443
-		// - https://github.com/VictoriaMetrics/victoriametrics-datasource/issues/59
-		q := req.URL.Query()
-		q.Set("datasource_type", "prometheus")
-		req.URL.RawQuery = q.Encode()
-		req.RequestURI = ""
-	}
-
-	vmalertProxy.ServeHTTP(w, req)
-}
-
-var (
-	vmalertProxyHost string
-	vmalertProxy     *nethttputil.ReverseProxy
-	vmuiConfig       string
-)
+var vmuiConfig string
 
 func initVMUIConfig() {
 	var cfg struct {
@@ -795,16 +757,3 @@ func initVMUIConfig() {
 	}
 	vmuiConfig = string(data)
 }
-
-// initVMAlertProxy must be called after flag.Parse(), since it uses command-line flags.
-func initVMAlertProxy() {
-	if len(*vmalertProxyURL) == 0 {
-		return
-	}
-	proxyURL, err := url.Parse(*vmalertProxyURL)
-	if err != nil {
-		logger.Fatalf("cannot parse -vmalert.proxyURL=%q: %s", *vmalertProxyURL, err)
-	}
-	vmalertProxyHost = proxyURL.Host
-	vmalertProxy = nethttputil.NewSingleHostReverseProxy(proxyURL)
-}

app/vmselect/prometheus/prometheus.go

@@ -28,6 +28,7 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fasttime"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/httputil"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
@@ -525,6 +526,7 @@ func DeleteHandler(startTime time.Time, r *http.Request) error {
 	if deletedCount > 0 {
 		promql.ResetRollupResultCache()
 	}
+	logger.Infof("/api/v1/admin/tsdb/delete_series has been called for %q. Deleted %d series.", sq.FiltersString(), deletedCount)
 	return nil
 }
 

app/vmstorage/main.go

@@ -30,6 +30,9 @@ var (
 		"See https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#retention. See also -retentionFilter")
 	futureRetention = flagutil.NewRetentionDuration("futureRetention", "2d", "Data with timestamps bigger than now+futureRetention is automatically deleted. "+
 		"The minimum futureRetention is 2 days. See https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#retention")
+	vmselectAddr                  = flag.String("vmselectAddr", "", "TCP address to accept connections from vmselect services")
+	vmselectDisableRPCCompression = flag.Bool("rpc.disableCompression", false, "Whether to disable compression of the data sent from vmstorage to vmselect. "+
+		"This reduces CPU usage at the cost of higher network bandwidth usage")
 	snapshotAuthKey   = flagutil.NewPassword("snapshotAuthKey", "authKey, which must be passed in query string to /snapshot* pages. It overrides -httpAuth.*")
 	forceMergeAuthKey = flagutil.NewPassword("forceMergeAuthKey", "authKey, which must be passed in query string to /internal/force_merge pages. It overrides -httpAuth.*")
 	forceFlushAuthKey = flagutil.NewPassword("forceFlushAuthKey", "authKey, which must be passed in query string to /internal/force_flush pages. It overrides -httpAuth.*")
@@ -108,7 +111,7 @@ func DataPath() string {
 }
 
 // Init initializes vmstorage.
-func Init(vmselectMaxConcurrentRequests int, resetCacheIfNeeded func(mrs []storage.MetricRow)) {
+func Init(vmselectMaxConcurrentRequests int, vmselectMaxQueueDuration time.Duration, resetCacheIfNeeded func(mrs []storage.MetricRow)) {
 	storage.SetDedupInterval(*minScrapeInterval)
 	storage.SetDataFlushInterval(*inmemoryDataFlushInterval)
 	storage.LegacySetRetentionTimezoneOffset(*retentionTimezoneOffset)
@@ -169,6 +172,21 @@ func Init(vmselectMaxConcurrentRequests int, resetCacheIfNeeded func(mrs []stora
 	storageMetrics.RegisterMetricsWriter(vmStorage.writeStorageMetrics)
 	metrics.RegisterSet(storageMetrics)
 
+	if *vmselectAddr != "" {
+		var err error
+		limits := vmselectapi.Limits{
+			MaxConcurrentRequests:         vmselectMaxConcurrentRequests,
+			MaxConcurrentRequestsFlagName: "search.maxConcurrentRequests",
+			MaxQueueDuration:              vmselectMaxQueueDuration,
+			MaxQueueDurationFlagName:      "search.maxQueueDuration",
+		}
+		api := newVMStorageWithTenantID(vmStorage)
+		vmselectSrv, err = vmselectapi.NewServer(*vmselectAddr, api, limits, *vmselectDisableRPCCompression)
+		if err != nil {
+			logger.Fatalf("cannot create a server with -vmselectAddr=%s: %s", *vmselectAddr, err)
+		}
+	}
+
 	VMInsertAPI = vmStorage
 	VMSelectAPI = vmStorage
 	GetSearch = vmStorage.GetSearch
@@ -191,6 +209,8 @@ var (
 
 	// TODO(@rtm0): Remove this dependency from vmalert-tool unit tests.
 	DebugFlush func()
+
+	vmselectSrv *vmselectapi.Server
 )
 
 // Stop stops the vmstorage
@@ -201,6 +221,10 @@ func Stop() {
 
 	logger.Infof("gracefully closing the storage at %s", *storageDataPath)
 	startTime := time.Now()
+
+	if vmselectSrv != nil {
+		vmselectSrv.MustStop()
+	}
 	vmStorage.Stop()
 	logger.Infof("successfully closed the storage in %.3f seconds", time.Since(startTime).Seconds())
 

app/vmstorage/vmstorage.go

@@ -164,6 +164,10 @@ func (vms *VMStorage) IsReadOnly() bool {
 }
 
 func (vms *VMStorage) InitSearch(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline uint64) (vmselectapi.BlockIterator, error) {
+	return vms.initSearch(qt, sq, nil, deadline)
+}
+
+func (vms *VMStorage) initSearch(qt *querytracer.Tracer, sq *storage.SearchQuery, marshal marshalFunc, deadline uint64) (vmselectapi.BlockIterator, error) {
 	vms.wg.Add(1)
 
 	tr := sq.GetTimeRange()
@@ -178,6 +182,7 @@ func (vms *VMStorage) InitSearch(qt *querytracer.Tracer, sq *storage.SearchQuery
 		return nil, fmt.Errorf("missing tag filters")
 	}
 	bi := getBlockIterator()
+	bi.marshal = marshal
 	bi.wgDone = vms.wg.Done
 	bi.sr.Init(qt, vms.s, tfss, tr, maxMetrics, deadline)
 	if err := bi.sr.Error(); err != nil {
@@ -198,11 +203,14 @@ func (vms *VMStorage) getMaxMetrics(searchQueryLimit int) int {
 	return searchQueryLimit
 }
 
+type marshalFunc func(dst []byte, src *storage.MetricBlock) []byte
+
 // blockIterator implements vmselectapi.BlockIterator
 type blockIterator struct {
-	sr     storage.Search
-	mb     storage.MetricBlock
-	wgDone func()
+	sr      storage.Search
+	mb      storage.MetricBlock
+	marshal marshalFunc
+	wgDone  func()
 }
 
 var blockIteratorsPool sync.Pool
@@ -231,7 +239,11 @@ func (bi *blockIterator) NextBlock(dst []byte) ([]byte, bool) {
 	mb := bi.mb
 	mb.MetricName = bi.sr.MetricBlockRef.MetricName
 	bi.sr.MetricBlockRef.BlockRef.MustReadBlock(&mb.Block)
-	dst = mb.Marshal(dst[:0])
+	if bi.marshal != nil {
+		dst = bi.marshal(dst[:0], &mb)
+	} else {
+		dst = mb.Marshal(dst[:0])
+	}
 	return dst, true
 }
 

app/vmstorage/vmstorage_with_tenant_id.go

@@ -0,0 +1,264 @@
+package vmstorage
+
+import (
+	"flag"
+	"fmt"
+	"math"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/metricnamestats"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage/metricsmetadata"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/vmselectapi"
+)
+
+var (
+	accountID = flag.Uint64("accountID", 0, "The accountID of the stored data")
+	projectID = flag.Uint64("projectID", 0, "The projectID of the stored data")
+)
+
+func newVMStorageWithTenantID(vms *VMStorage) *VMStorageWithTenantID {
+	if *accountID > math.MaxUint32 {
+		logger.Fatalf("-clusternative.accountID must to be in the range [0, %d], got %d", uint32(math.MaxUint32), *accountID)
+	}
+	if *projectID > math.MaxUint32 {
+		logger.Fatalf("-clusternative.projectID must to be in the range [0, %d], got %d", uint32(math.MaxUint32), *projectID)
+	}
+	return &VMStorageWithTenantID{
+		vms:       vms,
+		accountID: uint32(*accountID),
+		projectID: uint32(*projectID),
+	}
+}
+
+// VMStorageWithTenantID is a thin wrapper around VMStorage type that overrides
+// its methods to properly serve requests coming from a vmselect (require
+// tenantID).
+//
+// A new instance of this type should be created using
+// newVMStorageWithTenantID(). The created instance does not require closing.
+// The instance also does not take ownership of vms and it is the responsibility
+// of the caller to close vms.
+type VMStorageWithTenantID struct {
+	vms *VMStorage
+
+	accountID uint32
+	projectID uint32
+}
+
+// InitSearch initializes a storage search for a request initiated by a
+// vmselect.
+//
+// The search is initialized iff the search query is either multitenant or its
+// accountID and projectID match -accountID and -projectID flag values.
+// Otherwise, the method returns an interator that will return no data.
+//
+// The method also overrides the data format of the data returned by the
+// iterator by prepending accountID and projectID bytes to the metric name and
+// the data block (a format used in vmcluster).
+func (vmst *VMStorageWithTenantID) InitSearch(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline uint64) (vmselectapi.BlockIterator, error) {
+	if !sq.IsMultiTenant && (sq.AccountID != vmst.accountID || sq.ProjectID != vmst.projectID) {
+		return emptyBI, nil
+	}
+	return vmst.vms.initSearch(qt, sq, vmst.marshalMetricBlock, deadline)
+}
+
+var emptyBI = &emptyBlockIterator{}
+
+// emptyBlockIterator is an implementation of vmselectapi.BlockIterator that
+// always returns no data.
+type emptyBlockIterator struct{}
+
+func (*emptyBlockIterator) MustClose() {}
+
+func (*emptyBlockIterator) NextBlock(dst []byte) ([]byte, bool) {
+	return dst, false
+}
+
+func (*emptyBlockIterator) Error() error {
+	return nil
+}
+
+// marshalMetricBlock serializes a metric block in the format expected by
+// vmselect.
+//
+// vmselect expects metric names and data blocks to have the tenantID but
+// vmsingle does not have it. Therefore the tenantID needs to be included to
+// every metric name and block.
+func (vmst *VMStorageWithTenantID) marshalMetricBlock(dst []byte, src *storage.MetricBlock) []byte {
+	// Marshal metric name:
+	// 1. Marshal metric name length + accountID length + projectID length (in
+	//    bytes).
+	// 2. append accountID and projectID bytes
+	// 3. Finally append metric name bytes
+	dst = encoding.MarshalVarUint64(dst, uint64(len(src.MetricName))+8)
+	dst = encoding.MarshalUint32(dst, vmst.accountID)
+	dst = encoding.MarshalUint32(dst, vmst.projectID)
+	dst = append(dst, src.MetricName...)
+
+	// Marshal data block.
+	dst = encoding.MarshalUint32(dst, vmst.accountID)
+	dst = encoding.MarshalUint32(dst, vmst.projectID)
+	dst = storage.MarshalBlock(dst, &src.Block)
+
+	return dst
+}
+
+// SearchMetricNames searches the storage for metric names that match the query.
+//
+// If the query is not multitenant or the query accountID and projectID do not
+// match the -accoutID and -projectID flag values, the method will return an
+// empty result.
+//
+// Found metric names are prepended with accountID and projectID bytes (a format
+// used in vmcluster).
+func (vmst *VMStorageWithTenantID) SearchMetricNames(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline uint64) ([]string, error) {
+	if !sq.IsMultiTenant && (sq.AccountID != vmst.accountID || sq.ProjectID != vmst.projectID) {
+		return nil, nil
+	}
+
+	metricNames, err := vmst.vms.SearchMetricNames(qt, sq, deadline)
+	if err != nil {
+		return nil, err
+	}
+
+	// vmselect expects metric names to have the tenantID but vmsingle does not
+	// have it. Therefore the tenantID needs to be appended to every metric
+	// name.
+	dst := make([]byte, 0, 8)
+	dst = encoding.MarshalUint32(dst, vmst.accountID)
+	dst = encoding.MarshalUint32(dst, vmst.projectID)
+	tenantID := string(dst)
+
+	for i, metricName := range metricNames {
+		metricNames[i] = tenantID + metricName
+	}
+	return metricNames, nil
+}
+
+// LabelValues searches the storage for values that match the query and
+// correspond to a label whose name is `labelName`. The returned result
+// will contain not more than `maxLabelValues`.
+//
+// If the query is not multitenant or the query accountID and projectID do not
+// match the -accoutID and -projectID flag values, the method will return an
+// empty result.
+func (vmst *VMStorageWithTenantID) LabelValues(qt *querytracer.Tracer, sq *storage.SearchQuery, labelName string, maxLabelValues int, deadline uint64) ([]string, error) {
+	if !sq.IsMultiTenant && (sq.AccountID != vmst.accountID || sq.ProjectID != vmst.projectID) {
+		return nil, nil
+	}
+	return vmst.vms.LabelValues(qt, sq, labelName, maxLabelValues, deadline)
+}
+
+// TagValueSuffixes searches the storage for Graphite tag value suffixes. The
+// returned result will contain not more than `maxSuffixes`.
+//
+// If the query is not multitenant or the query accountID and projectID do not
+// match the -accoutID and -projectID flag values, the method will return an
+// empty result.
+func (vmst *VMStorageWithTenantID) TagValueSuffixes(qt *querytracer.Tracer, accountID, projectID uint32, tr storage.TimeRange, tagKey, tagValuePrefix string, delimiter byte, maxSuffixes int, deadline uint64) ([]string, error) {
+	if accountID != vmst.accountID || projectID != vmst.projectID {
+		return nil, nil
+	}
+	return vmst.vms.TagValueSuffixes(qt, accountID, projectID, tr, tagKey, tagValuePrefix, delimiter, maxSuffixes, deadline)
+}
+
+// LabelNames searches the storage for label names that match the query.
+// The returned result will contain not more than `maxLabelNames`.
+//
+// If the query is not multitenant or the query accountID and projectID do not
+// match the -accoutID and -projectID flag values, the method will return an
+// empty result.
+func (vmst *VMStorageWithTenantID) LabelNames(qt *querytracer.Tracer, sq *storage.SearchQuery, maxLabelNames int, deadline uint64) ([]string, error) {
+	if !sq.IsMultiTenant && (sq.AccountID != vmst.accountID || sq.ProjectID != vmst.projectID) {
+		return nil, nil
+	}
+	return vmst.vms.LabelNames(qt, sq, maxLabelNames, deadline)
+}
+
+// SeriesCount returns the total number of metrics stored in the database.
+//
+// The method may return inflated numbers. How inflated the count depends
+// on the churn rate and the retention period. For example, if a metric lasts
+// for 2 months, it will be counted twice.
+//
+// The method also counts the deleted metrics.
+//
+// If the query is not multitenant or the query accountID and projectID do not
+// match the -accoutID and -projectID flag values, the method will return 0.
+func (vmst *VMStorageWithTenantID) SeriesCount(qt *querytracer.Tracer, accountID, projectID uint32, deadline uint64) (uint64, error) {
+	if accountID != vmst.accountID || projectID != vmst.projectID {
+		return 0, nil
+	}
+	return vmst.vms.SeriesCount(qt, accountID, projectID, deadline)
+}
+
+// Tenants returns just one tenant consisting of the -accountID and -projectID
+// flag values.
+func (vmst *VMStorageWithTenantID) Tenants(qt *querytracer.Tracer, tr storage.TimeRange, deadline uint64) ([]string, error) {
+	tenantID := fmt.Sprintf("%d:%d", vmst.accountID, vmst.projectID)
+	return []string{tenantID}, nil
+}
+
+// TSDBStatus retrieves the status for metrics that match to the search query.
+//
+// If the query is not multitenant or the query accountID and projectID do not
+// match the -accoutID and -projectID flag values, the method will return empty
+// status.
+func (vmst *VMStorageWithTenantID) TSDBStatus(qt *querytracer.Tracer, sq *storage.SearchQuery, focusLabel string, topN int, deadline uint64) (*storage.TSDBStatus, error) {
+	if !sq.IsMultiTenant && (sq.AccountID != vmst.accountID || sq.ProjectID != vmst.projectID) {
+		return &storage.TSDBStatus{}, nil
+	}
+	return vmst.vms.TSDBStatus(qt, sq, focusLabel, topN, deadline)
+}
+
+// DeleteSeries marks as deleted metrics that match the search query.
+// The method returns the number of deleted metrics.
+//
+// If the query is not multitenant or the query accountID and projectID do not
+// match the -accoutID and -projectID flag values, no metrics will be deleted
+// and the method will return 0.
+func (vmst *VMStorageWithTenantID) DeleteSeries(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline uint64) (int, error) {
+	if !sq.IsMultiTenant && (sq.AccountID != vmst.accountID || sq.ProjectID != vmst.projectID) {
+		return 0, nil
+	}
+	return vmst.vms.DeleteSeries(qt, sq, deadline)
+}
+
+// RegisterMetricNames registers metric names in the index, the sample values
+// and timestamps are ignored.
+func (vmst *VMStorageWithTenantID) RegisterMetricNames(qt *querytracer.Tracer, mrs []storage.MetricRow, deadline uint64) error {
+	return vmst.vms.RegisterMetricNames(qt, mrs, deadline)
+}
+
+// GetMetricNamesUsageStats retrieves the usage stats for metrics whose name
+// matches the pattern.
+//
+// If the request is not multitenant or the request accountID and projectID do
+// not match the -accoutID and -projectID flag values, no metrics will be
+// deleted and the method will return 0.
+func (vmst *VMStorageWithTenantID) GetMetricNamesUsageStats(qt *querytracer.Tracer, tt *storage.TenantToken, limit, le int, matchPattern string, deadline uint64) (metricnamestats.StatsResult, error) {
+	if tt != nil && (tt.AccountID != vmst.accountID || tt.ProjectID != vmst.projectID) {
+		return metricnamestats.StatsResult{}, nil
+	}
+	return vmst.vms.GetMetricNamesUsageStats(qt, tt, limit, le, matchPattern, deadline)
+}
+
+// ResetMetricNamesUsageStats resets the metric name usage stats.
+func (vmst *VMStorageWithTenantID) ResetMetricNamesUsageStats(qt *querytracer.Tracer, deadline uint64) error {
+	return vmst.vms.ResetMetricNamesUsageStats(qt, deadline)
+}
+
+// GetMetadataRecords retrieves the metadata for the metricName.
+//
+// If the request is not multitenant or the request accountID and projectID do
+// not match the -accoutID and -projectID flag values, no metrics will be
+// deleted and the method will return 0.
+func (vmst *VMStorageWithTenantID) GetMetadataRecords(qt *querytracer.Tracer, tt *storage.TenantToken, limit int, metricName string, deadline uint64) ([]*metricsmetadata.Row, error) {
+	if tt != nil && (tt.AccountID != vmst.accountID || tt.ProjectID != vmst.projectID) {
+		return nil, nil
+	}
+	return vmst.vms.GetMetadataRecords(qt, tt, limit, metricName, deadline)
+}

apptest/testdata.go

@@ -0,0 +1,358 @@
+package apptest
+
+import (
+	"fmt"
+	"slices"
+)
+
+type TestData struct {
+	Samples              []string
+	Step                 int64
+	WantSeries           []map[string]string
+	WantLabels           []string
+	WantLabelValues      []string
+	WantQueryResults     []*QueryResult
+	WantMetadata         map[string][]MetadataEntry
+	WantMetricNamesStats []MetricNamesStatsRecord
+}
+
+func GenerateTestData(prefix string, numMetrics, start, end int64) TestData {
+	d := TestData{
+		Samples:              []string{},
+		Step:                 (end - start) / numMetrics,
+		WantSeries:           make([]map[string]string, numMetrics),
+		WantLabels:           make([]string, numMetrics),
+		WantLabelValues:      make([]string, numMetrics),
+		WantQueryResults:     make([]*QueryResult, numMetrics),
+		WantMetadata:         make(map[string][]MetadataEntry),
+		WantMetricNamesStats: make([]MetricNamesStatsRecord, numMetrics),
+	}
+	for i := range numMetrics {
+		metricName := fmt.Sprintf("%s_%04d", prefix, i)
+		metricHelp := fmt.Sprintf("# HELP %s some help message", metricName)
+		metricType := fmt.Sprintf("# TYPE %s gauge", metricName)
+		labelName := fmt.Sprintf("label_%04d", i)
+		labelValue := fmt.Sprintf("value_%04d", i)
+		value := i
+		timestamp := start + i*d.Step
+		sample := fmt.Sprintf(`%s{%s="value", label="%s"} %d %d`, metricName, labelName, labelValue, value, timestamp)
+
+		d.Samples = append(d.Samples, metricHelp, metricType, sample)
+		d.WantSeries[i] = map[string]string{
+			"__name__": metricName,
+			labelName:  "value",
+			"label":    labelValue,
+		}
+		d.WantLabels[i] = labelName
+		d.WantLabelValues[i] = labelValue
+		d.WantQueryResults[i] = &QueryResult{
+			Metric: map[string]string{
+				"__name__": metricName,
+				labelName:  "value",
+				"label":    labelValue,
+			},
+			Samples: []*Sample{{Timestamp: timestamp, Value: float64(value)}},
+		}
+		d.WantMetadata[metricName] = []MetadataEntry{{Help: "some help message", Type: "gauge"}}
+		d.WantMetricNamesStats[i].MetricName = metricName
+	}
+	d.WantLabels = append(d.WantLabels, "__name__", "label")
+	slices.Sort(d.WantLabels)
+	return d
+}
+
+// AssertSeries retrieves metric names from the storage and compares the result
+// with the expected one.
+func AssertSeries(tc *TestCase, app PrometheusQuerier, metricNameRE, tenantID string, start, end int64, want []map[string]string) {
+	tc.T().Helper()
+
+	query := fmt.Sprintf(`{__name__=~"%s"}`, metricNameRE)
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /prometheus/api/v1/series response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.PrometheusAPIV1Series(tc.T(), query, QueryOpts{
+				Tenant: tenantID,
+				Start:  fmt.Sprintf("%d", start),
+				End:    fmt.Sprintf("%d", end),
+			}).Sort()
+		},
+		Want: &PrometheusAPIV1SeriesResponse{
+			Status: "success",
+			Data:   want,
+		},
+		Retries: 1000,
+		FailNow: true,
+	})
+}
+
+// AssertSeriesCount retrieves series count and compares it with expected one.
+func AssertSeriesCount(tc *TestCase, app PrometheusQuerier, tenantID string, start, end int64, want uint64) {
+	tc.T().Helper()
+
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /prometheus/api/v1/series/count response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.PrometheusAPIV1SeriesCount(tc.T(), QueryOpts{
+				Tenant: tenantID,
+				Start:  fmt.Sprintf("%d", start),
+				End:    fmt.Sprintf("%d", end),
+			})
+		},
+		Want: &PrometheusAPIV1SeriesCountResponse{
+			Status: "success",
+			Data:   []uint64{want},
+		},
+		FailNow: true,
+	})
+}
+
+// AssertLabels retrieves label names from the storage and compares the result
+// with the expected one.
+func AssertLabels(tc *TestCase, app PrometheusQuerier, metricNameRE, tenantID string, start, end int64, want []string) {
+	tc.T().Helper()
+
+	query := fmt.Sprintf(`{__name__=~"%s"}`, metricNameRE)
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /prometheus/api/v1/labels response",
+		Got: func() any {
+			tc.T().Helper()
+			res := app.PrometheusAPIV1Labels(tc.T(), query, QueryOpts{
+				Tenant: tenantID,
+				Start:  fmt.Sprintf("%d", start),
+				End:    fmt.Sprintf("%d", end),
+			})
+			slices.Sort(res.Data)
+			return res
+		},
+		Want: &PrometheusAPIV1LabelsResponse{
+			Status: "success",
+			Data:   want,
+		},
+		FailNow: true,
+	})
+}
+
+// AssertLabelValues retrieves values for the label whose name is labelName for
+// the series whose name mathes metricNameRE, compares the result with the
+// expected one.
+func AssertLabelValues(tc *TestCase, app PrometheusQuerier, metricNameRE, labelName, tenantID string, start, end int64, want []string) {
+	tc.T().Helper()
+
+	query := fmt.Sprintf(`{__name__=~"%s"}`, metricNameRE)
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /prometheus/api/v1/labels/.../values response",
+		Got: func() any {
+			tc.T().Helper()
+			res := app.PrometheusAPIV1LabelValues(tc.T(), labelName, query, QueryOpts{
+				Tenant: tenantID,
+				Start:  fmt.Sprintf("%d", start),
+				End:    fmt.Sprintf("%d", end),
+			})
+			slices.Sort(res.Data)
+			return res
+		},
+		Want: &PrometheusAPIV1LabelValuesResponse{
+			Status: "success",
+			Data:   want,
+		},
+		FailNow: true,
+	})
+}
+
+// AssertQueryResults sends a data query to storage and compares the query
+// result with the expected one.
+func AssertQueryResults(tc *TestCase, app PrometheusQuerier, metricNameRE, tenantID string, start, end, step int64, want []*QueryResult) {
+	tc.T().Helper()
+
+	query := fmt.Sprintf(`{__name__=~"%s"}`, metricNameRE)
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /prometheus/api/v1/query_range response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.PrometheusAPIV1QueryRange(tc.T(), query, QueryOpts{
+				Tenant:      tenantID,
+				Start:       fmt.Sprintf("%d", start),
+				End:         fmt.Sprintf("%d", end),
+				Step:        fmt.Sprintf("%dms", step),
+				MaxLookback: fmt.Sprintf("%dms", step-1),
+				NoCache:     "1",
+			})
+		},
+		Want: &PrometheusAPIV1QueryResponse{
+			Status: "success",
+			Data: &QueryData{
+				ResultType: "matrix",
+				Result:     want,
+			},
+		},
+		FailNow: true,
+	})
+}
+
+func AssertMetadata(tc *TestCase, app PrometheusQuerier, metricName, tenantID string, want map[string][]MetadataEntry) {
+	tc.T().Helper()
+
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /prometheus/api/v1/metadata response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.PrometheusAPIV1Metadata(tc.T(), metricName, 0, QueryOpts{
+				Tenant: tenantID,
+			})
+		},
+		Want: &PrometheusAPIV1Metadata{
+			Status: "success",
+			Data:   want,
+		},
+		FailNow: true,
+	})
+}
+
+func AssertMetricNamesStats(tc *TestCase, app PrometheusQuerier, metricNameRE, tenantID string, want []MetricNamesStatsRecord) {
+	tc.T().Helper()
+
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /prometheus/api/v1/status/metric_names_stats response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.PrometheusAPIV1StatusMetricNamesStats(tc.T(), "", "", metricNameRE, QueryOpts{
+				Tenant: tenantID,
+			})
+		},
+		Want: MetricNamesStatsResponse{
+			Records: want,
+		},
+		FailNow: true,
+	})
+
+}
+
+// GraphiteTestData holds the data samples in Graphite Pickle format, distance
+// between samples in milliseconds and expected responses for various Graphite
+// API endpoints.
+type GraphiteTestData struct {
+	Samples             []string
+	Step                int64
+	WantMetricsIndex    []string
+	WantMetricsFind     []GraphiteMetric
+	WantMetricsExpand   []string
+	WantRenderedTargets []GraphiteRenderedTarget
+}
+
+// GenerateGraphiteTestData generates Graphite test data.
+func GenerateGraphiteTestData(prefix string, numMetrics, start, end int64) GraphiteTestData {
+	d := GraphiteTestData{
+		Samples:             make([]string, numMetrics),
+		Step:                (end - start) / numMetrics,
+		WantMetricsIndex:    make([]string, numMetrics),
+		WantMetricsFind:     make([]GraphiteMetric, numMetrics),
+		WantMetricsExpand:   make([]string, numMetrics),
+		WantRenderedTargets: make([]GraphiteRenderedTarget, numMetrics),
+	}
+
+	datapoints := make([][2]float64, numMetrics)
+	for i := range numMetrics {
+		timestamp := (start + i*d.Step) / 1000
+		datapoints[i][1] = float64(timestamp)
+	}
+
+	for i := range numMetrics {
+		suffix := fmt.Sprintf("%04d", i)
+		metricName := fmt.Sprintf("%s.%s", prefix, suffix)
+		value := i
+		timestamp := (start + i*d.Step) / 1000
+		sample := fmt.Sprintf(`%s %d %d`, metricName, value, timestamp)
+
+		d.Samples[i] = sample
+		d.WantMetricsIndex[i] = metricName
+		d.WantMetricsFind[i].Id = metricName
+		d.WantMetricsFind[i].Text = suffix
+		d.WantMetricsFind[i].Leaf = 1
+		d.WantMetricsExpand[i] = metricName
+		d.WantRenderedTargets[i].Target = metricName
+		d.WantRenderedTargets[i].Datapoints = slices.Clone(datapoints)
+		d.WantRenderedTargets[i].Datapoints[i][0] = float64(value)
+	}
+	return d
+}
+
+// AssertGraphiteMetricsIndex retrieves all metrics by sending a request to
+// /graphite/metrics/index.json and compares the result with the expected one.
+func AssertGraphiteMetricsIndex(tc *TestCase, app PrometheusQuerier, tenantID string, want []string) {
+	tc.T().Helper()
+
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /graphite/metrics/index.json response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.GraphiteMetricsIndex(tc.T(), QueryOpts{
+				Tenant: tenantID,
+			})
+		},
+		Want:    want,
+		Retries: 30,
+		FailNow: true,
+	})
+
+}
+
+// AssertGraphiteMetricsFind finds metric names by sending a request to
+// /graphite/metrics/find and compares the result with the expected one.
+func AssertGraphiteMetricsFind(tc *TestCase, app PrometheusQuerier, query, tenantID string, want []GraphiteMetric) {
+	tc.T().Helper()
+
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /graphite/metrics/find response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.GraphiteMetricsFind(tc.T(), query, QueryOpts{
+				Tenant: tenantID,
+			})
+		},
+		Want:    want,
+		FailNow: true,
+	})
+
+}
+
+// AssertGraphiteMetricsFind expands metric names by sending a request to
+// /graphite/metrics/expand and compares the result with the expected one.
+func AssertGraphiteMetricsExpand(tc *TestCase, app PrometheusQuerier, query, tenantID string, want []string) {
+	tc.T().Helper()
+
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /graphite/metrics/expand response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.GraphiteMetricsExpand(tc.T(), query, QueryOpts{
+				Tenant: tenantID,
+			})
+		},
+		Want:    want,
+		FailNow: true,
+	})
+
+}
+
+// AssertGraphiteRender retieves metric raw data by sending a request to
+// /graphite/render and compares the result with the expected one.
+func AssertGraphiteRender(tc *TestCase, app PrometheusQuerier, target, tenantID string, from, until, step int64, want []GraphiteRenderedTarget) {
+	tc.T().Helper()
+
+	tc.Assert(&AssertOptions{
+		Msg: "unexpected /graphite/render response",
+		Got: func() any {
+			tc.T().Helper()
+			return app.GraphiteRender(tc.T(), target, QueryOpts{
+				Tenant:      tenantID,
+				From:        fmt.Sprintf("%d", from/1000),
+				Until:       fmt.Sprintf("%d", until/1000),
+				StorageStep: fmt.Sprintf("%dms", step),
+			})
+		},
+		Want:    want,
+		FailNow: true,
+	})
+}

apptest/tests/vmsingle_vmselect_rpc_test.go

@@ -0,0 +1,216 @@
+package tests
+
+import (
+	"fmt"
+	"path/filepath"
+	"slices"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/apptest"
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestMixedPrometheusQueries(t *testing.T) {
+	tc := apptest.NewTestCase(t)
+	defer tc.Stop()
+
+	const (
+		accountID1 = 12
+		projectID1 = 34
+		accountID2 = 56
+		projectID2 = 78
+		numMetrics = 10
+	)
+	tenantID1 := fmt.Sprintf("%d:%d", accountID1, projectID1)
+	tenantID2 := fmt.Sprintf("%d:%d", accountID2, projectID2)
+	start := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC).UnixMilli()
+	end := time.Date(2026, 1, 2, 0, 0, 0, 0, time.UTC).UnixMilli()
+	data := apptest.GenerateTestData("metric", numMetrics, start, end)
+	emptySeries := []map[string]string{}
+	emptyLabels := []string{}
+	emptyLabelValues := []string{}
+	emptyQueryResults := []*apptest.QueryResult{}
+	emptyMetadata := map[string][]apptest.MetadataEntry{}
+	emptyMetricNamesStats := []apptest.MetricNamesStatsRecord{}
+
+	vmsingle := tc.MustStartVmsingle("vmsingle", []string{
+		"-storageDataPath=" + filepath.Join(tc.Dir(), "vmsingle"),
+		"-retentionPeriod=100y",
+		fmt.Sprintf("-accountID=%d", accountID1),
+		fmt.Sprintf("-projectID=%d", projectID1),
+	})
+	vmselect := tc.MustStartVmselect("vmselect", []string{
+		"-storageNode=" + vmsingle.VmselectAddr(),
+	})
+
+	vmsingle.PrometheusAPIV1ImportPrometheus(tc.T(), data.Samples, apptest.QueryOpts{})
+	vmsingle.ForceFlush(t)
+
+	// Ensure vmsingle returns data.
+	apptest.AssertSeries(tc, vmsingle, "metric.*", "", start, end, data.WantSeries)
+	apptest.AssertSeriesCount(tc, vmsingle, "", start, end, numMetrics)
+	apptest.AssertLabels(tc, vmsingle, "metric.*", "", start, end, data.WantLabels)
+	apptest.AssertLabelValues(tc, vmsingle, "metric.*", "label", "", start, end, data.WantLabelValues)
+	apptest.AssertQueryResults(tc, vmsingle, "metric.*", "", start, end, data.Step, data.WantQueryResults)
+	apptest.AssertMetadata(tc, vmsingle, "", "", data.WantMetadata)
+	for i := range data.WantMetricNamesStats {
+		data.WantMetricNamesStats[i].QueryRequestsCount = 1
+	}
+	apptest.AssertMetricNamesStats(tc, vmsingle, "", "", data.WantMetricNamesStats)
+
+	// Check that current vmsingle tenant (configured via flags) is tenant1.
+	gotAdminTenantsResponse := vmselect.APIV1AdminTenants(t, apptest.QueryOpts{})
+	wantAdminTenantsResponse := &apptest.AdminTenantsResponse{
+		Status: "success",
+		Data:   []string{tenantID1},
+	}
+	if diff := cmp.Diff(wantAdminTenantsResponse, gotAdminTenantsResponse); diff != "" {
+		t.Fatalf("unexpected tenants (-want, +got):\n%s", diff)
+	}
+
+	// Ensure vmselect returns data for tenant1.
+	apptest.AssertSeries(tc, vmselect, "metric.*", tenantID1, start, end, data.WantSeries)
+	apptest.AssertSeriesCount(tc, vmselect, tenantID1, start, end, numMetrics)
+	apptest.AssertLabels(tc, vmselect, "metric.*", tenantID1, start, end, data.WantLabels)
+	apptest.AssertLabelValues(tc, vmselect, "metric.*", "label", tenantID1, start, end, data.WantLabelValues)
+	apptest.AssertQueryResults(tc, vmselect, "metric.*", tenantID1, start, end, data.Step, data.WantQueryResults)
+	apptest.AssertMetadata(tc, vmselect, "", tenantID1, data.WantMetadata)
+	for i := range data.WantMetricNamesStats {
+		data.WantMetricNamesStats[i].QueryRequestsCount = 2
+	}
+	apptest.AssertMetricNamesStats(tc, vmselect, "", tenantID1, data.WantMetricNamesStats)
+
+	// Ensure vmselect does not return any data for tenant2.
+	apptest.AssertSeries(tc, vmselect, "metric.*", tenantID2, start, end, emptySeries)
+	apptest.AssertSeriesCount(tc, vmselect, tenantID2, start, end, 0)
+	apptest.AssertLabels(tc, vmselect, "metric.*", tenantID2, start, end, emptyLabels)
+	apptest.AssertLabelValues(tc, vmselect, "metric.*", "label", tenantID2, start, end, emptyLabelValues)
+	apptest.AssertQueryResults(tc, vmselect, "metric.*", tenantID2, start, end, data.Step, emptyQueryResults)
+	apptest.AssertMetadata(tc, vmselect, "", tenantID2, emptyMetadata)
+	apptest.AssertMetricNamesStats(tc, vmselect, "", tenantID2, emptyMetricNamesStats)
+
+	// Ensure vmselect returns data for multitenant.
+	for _, v := range data.WantSeries {
+		v["vm_account_id"] = strconv.Itoa(accountID1)
+		v["vm_project_id"] = strconv.Itoa(projectID1)
+	}
+	apptest.AssertSeries(tc, vmselect, "metric.*", "multitenant", start, end, data.WantSeries)
+	data.WantLabels = append(data.WantLabels, "vm_account_id", "vm_project_id")
+	apptest.AssertLabels(tc, vmselect, "metric.*", "multitenant", start, end, data.WantLabels)
+	apptest.AssertLabelValues(tc, vmselect, "metric.*", "label", "multitenant", start, end, data.WantLabelValues)
+	for _, v := range data.WantQueryResults {
+		v.Metric["vm_account_id"] = strconv.Itoa(accountID1)
+		v.Metric["vm_project_id"] = strconv.Itoa(projectID1)
+	}
+	apptest.AssertQueryResults(tc, vmselect, "metric.*", "multitenant", start, end, data.Step, data.WantQueryResults)
+	apptest.AssertMetadata(tc, vmselect, "", "multitenant", data.WantMetadata)
+	for i := range data.WantMetricNamesStats {
+		data.WantMetricNamesStats[i].QueryRequestsCount = 3
+	}
+	apptest.AssertMetricNamesStats(tc, vmselect, "", "multitenant", data.WantMetricNamesStats)
+}
+
+func TestMixedDeleteSeries(t *testing.T) {
+	tc := apptest.NewTestCase(t)
+	defer tc.Stop()
+
+	const (
+		accountID1 = 12
+		projectID1 = 34
+		accountID2 = 56
+		projectID2 = 78
+		numMetrics = 10
+	)
+	tenantID1 := fmt.Sprintf("%d:%d", accountID1, projectID1)
+	tenantID2 := fmt.Sprintf("%d:%d", accountID2, projectID2)
+	start := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC).UnixMilli()
+	end := time.Date(2026, 1, 2, 0, 0, 0, 0, time.UTC).UnixMilli()
+	data1 := apptest.GenerateTestData("metric1", numMetrics, start, end)
+	data2 := apptest.GenerateTestData("metric2", numMetrics, start, end)
+	emptySeries := []map[string]string{}
+
+	vmsingle := tc.MustStartVmsingle("vmsingle", []string{
+		"-storageDataPath=" + filepath.Join(tc.Dir(), "vmsingle"),
+		"-retentionPeriod=100y",
+		fmt.Sprintf("-accountID=%d", accountID1),
+		fmt.Sprintf("-projectID=%d", projectID1),
+	})
+	vmselect := tc.MustStartVmselect("vmselect", []string{
+		"-storageNode=" + vmsingle.VmselectAddr(),
+	})
+
+	vmsingle.PrometheusAPIV1ImportPrometheus(tc.T(), data1.Samples, apptest.QueryOpts{})
+	vmsingle.PrometheusAPIV1ImportPrometheus(tc.T(), data2.Samples, apptest.QueryOpts{})
+	vmsingle.ForceFlush(t)
+
+	wantSeries12 := slices.Concat(data1.WantSeries, data2.WantSeries)
+	apptest.AssertSeries(tc, vmsingle, "metric.*", "", start, end, wantSeries12)
+
+	vmselect.PrometheusAPIV1AdminTSDBDeleteSeries(tc.T(), `{__name__=~"metric1.*"}`, apptest.QueryOpts{
+		Tenant: tenantID1,
+	})
+	apptest.AssertSeries(tc, vmsingle, "metric.*", "", start, end, data2.WantSeries)
+	vmselect.PrometheusAPIV1AdminTSDBDeleteSeries(tc.T(), `{__name__=~"metric2.*"}`, apptest.QueryOpts{
+		Tenant: tenantID2,
+	})
+	apptest.AssertSeries(tc, vmsingle, "metric.*", "", start, end, data2.WantSeries)
+	vmselect.PrometheusAPIV1AdminTSDBDeleteSeries(tc.T(), `{__name__=~"metric2.*"}`, apptest.QueryOpts{
+		Tenant: "multitenant",
+	})
+	apptest.AssertSeries(tc, vmsingle, "metric.*", "", start, end, emptySeries)
+}
+
+func TestMixedGraphiteQueries(t *testing.T) {
+	tc := apptest.NewTestCase(t)
+	defer tc.Stop()
+
+	const (
+		accountID1 = 12
+		projectID1 = 34
+		accountID2 = 56
+		projectID2 = 78
+		numMetrics = 10
+	)
+	tenantID1 := fmt.Sprintf("%d:%d", accountID1, projectID1)
+	tenantID2 := fmt.Sprintf("%d:%d", accountID2, projectID2)
+	start := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC).UnixMilli()
+	end := time.Date(2026, 1, 2, 0, 0, 0, 0, time.UTC).UnixMilli()
+	data := apptest.GenerateGraphiteTestData("metric", numMetrics, start, end)
+	emptyMetricsIndex := []string{}
+	emptyMetricsFind := []apptest.GraphiteMetric{}
+	emptyMetricsExpand := []string{}
+	emptyRenderedTargets := []apptest.GraphiteRenderedTarget{}
+
+	vmsingle := tc.MustStartVmsingle("vmsingle", []string{
+		"-storageDataPath=" + filepath.Join(tc.Dir(), "vmsingle"),
+		"-retentionPeriod=100y",
+		fmt.Sprintf("-accountID=%d", accountID1),
+		fmt.Sprintf("-projectID=%d", projectID1),
+	})
+	vmselect := tc.MustStartVmselect("vmselect", []string{
+		"-storageNode=" + vmsingle.VmselectAddr(),
+	})
+
+	vmsingle.GraphiteWrite(tc.T(), data.Samples, apptest.QueryOpts{})
+	vmsingle.ForceFlush(t)
+
+	// Ensure vmsingle returns data.
+	apptest.AssertGraphiteMetricsIndex(tc, vmsingle, "", data.WantMetricsIndex)
+	apptest.AssertGraphiteMetricsFind(tc, vmsingle, "metric.*", "", data.WantMetricsFind)
+	apptest.AssertGraphiteMetricsExpand(tc, vmsingle, "metric.*", "", data.WantMetricsExpand)
+	apptest.AssertGraphiteRender(tc, vmsingle, "metric.*", "", start, end, data.Step, data.WantRenderedTargets)
+
+	// Ensure vmselect returns data for tenant1.
+	apptest.AssertGraphiteMetricsIndex(tc, vmselect, tenantID1, data.WantMetricsIndex)
+	apptest.AssertGraphiteMetricsFind(tc, vmselect, "metric.*", tenantID1, data.WantMetricsFind)
+	apptest.AssertGraphiteMetricsExpand(tc, vmselect, "metric.*", tenantID1, data.WantMetricsExpand)
+	apptest.AssertGraphiteRender(tc, vmselect, "metric.*", tenantID1, start, end, data.Step, data.WantRenderedTargets)
+
+	// Ensure vmselect does not return any data for tenant2.
+	apptest.AssertGraphiteMetricsIndex(tc, vmselect, tenantID2, emptyMetricsIndex)
+	apptest.AssertGraphiteMetricsFind(tc, vmselect, "metric.*", tenantID2, emptyMetricsFind)
+	apptest.AssertGraphiteMetricsExpand(tc, vmselect, "metric.*", tenantID2, emptyMetricsExpand)
+	apptest.AssertGraphiteRender(tc, vmselect, "metric.*", tenantID2, start, end, data.Step, emptyRenderedTargets)
+}

apptest/vmsingle.go

@@ -25,12 +25,14 @@ func StartVmsingle(instance string, flags []string, cli *Client, output io.Write
 			"-httpListenAddr":     "127.0.0.1:0",
 			"-graphiteListenAddr": "127.0.0.1:0",
 			"-opentsdbListenAddr": "127.0.0.1:0",
+			"-vmselectAddr":       "127.0.0.1:0",
 		},
 		extractREs: []*regexp.Regexp{
 			storageDataPathRE,
 			httpListenAddrRE,
 			graphiteListenAddrRE,
 			openTSDBListenAddrRE,
+			vmselectAddrRE,
 		},
 		output: output,
 	})
@@ -43,6 +45,7 @@ func StartVmsingle(instance string, flags []string, cli *Client, output io.Write
 		httpListenAddr:     stderrExtracts[1],
 		graphiteListenAddr: stderrExtracts[2],
 		openTSDBListenAddr: stderrExtracts[3],
+		vmselectAddr:       stderrExtracts[4],
 	}), nil
 }
 
@@ -51,6 +54,7 @@ type vmsingleRuntimeValues struct {
 	httpListenAddr     string
 	graphiteListenAddr string
 	openTSDBListenAddr string
+	vmselectAddr       string
 }
 
 func newVmsingle(app *app, cli *Client, rt vmsingleRuntimeValues) *Vmsingle {
@@ -85,6 +89,7 @@ func newVmsingle(app *app, cli *Client, rt vmsingleRuntimeValues) *Vmsingle {
 		},
 		storageDataPath: rt.storageDataPath,
 		httpListenAddr:  rt.httpListenAddr,
+		vmselectAddr:    rt.vmselectAddr,
 	}
 }
 
@@ -99,6 +104,7 @@ type Vmsingle struct {
 
 	storageDataPath string
 	httpListenAddr  string
+	vmselectAddr    string
 }
 
 // HTTPAddr returns the address at which the vminsert process is
@@ -107,6 +113,12 @@ func (app *Vmsingle) HTTPAddr() string {
 	return app.httpListenAddr
 }
 
+// VmselectAddr returns the address at which the vmsingle process is listening
+// for vmselect connections.
+func (app *Vmsingle) VmselectAddr() string {
+	return app.vmselectAddr
+}
+
 // String returns the string representation of the vmsingle app state.
 func (app *Vmsingle) String() string {
 	return fmt.Sprintf("{app: %s storageDataPath: %q httpListenAddr: %q}", []any{

docs/guides/guide-vmcluster-multiple-retention-setup/README.md

@@ -6,45 +6,348 @@ build:
 sitemap:
   disable: true
 ---
-**Objective**
 
-Setup Victoria Metrics Cluster with support of multiple retention periods within one installation.
+> [VictoriaMetrics Enterprise](https://docs.victoriametrics.com/victoriametrics/enterprise/) supports specifying multiple retentions for distinct sets of time series and tenants. If you are an Enterprise user, [configure multiple retentions directly through retention filters](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#retention-filters) instead of following this guide.
 
-**Enterprise Solution**
+This guide explains how to set up multiple retentions using an [open-source VictoriaMetrics Cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/).
 
-[VictoriaMetrics Enterprise](https://docs.victoriametrics.com/victoriametrics/enterprise/) supports specifying multiple retentions
-for distinct sets of time series and [tenants](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#multitenancy)
-via [retention filters](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#retention-filters).
+## Overview
 
-**Open Source Solution**
+VictoriaMetrics retains metrics by default for **1 month**. You can change data retention with the [`-retentionPeriod` command-line flag](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#retention), but this value applies to **all time series stored** on a given `vmstorage` node and cannot be customized per tenant or per metric in the open source version. 
 
-Community version of VictoriaMetrics supports only one retention period per `vmstorage` node via [-retentionPeriod](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#retention) command-line flag.
+The core idea of this guide is to run **separate logic groups of storages** (or even clusters) with individual `-retentionPeriod` settings, while still providing a single unified write and read path via vmagent and vmselect.
 
-A multi-retention setup can be implemented by dividing a [victoriametrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/) into logical groups with different retentions.
+## Multi-Retention Architecture
 
-Example:
-Setup should handle 3 different retention groups 3months, 1year and 3 years.
-Solution contains 3 groups of vmstorages + vminserts and one group of vmselects. Routing is done by [vmagent](https://docs.victoriametrics.com/victoriametrics/vmagent/)
-by [splitting data streams](https://docs.victoriametrics.com/victoriametrics/vmagent/#splitting-data-streams-among-multiple-systems). 
-The [-retentionPeriod](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#retention) sets how long to keep the metrics.
+To support multiple retentions with the open source version of VictoriaMetrics cluster, you can split the cluster into several logical groups of storage nodes. Each group is configured with a different `-retentionPeriod` and receives only the data that must follow that retention. 
 
-The diagram below shows a proposed solution
+Each storage group is connected to a separate vminsert, while a shared vmselect layer queries across all storage groups so that dashboards and alerts continue to see a single unified VictoriaMetrics backend.
 
 ![Setup](setup.webp)
 
-**Implementation Details**
+In the example used throughout this guide, the cluster is divided into three groups: 
 
-1. Groups of vminserts A know about only vmstorages A and this is explicitly specified via `-storageNode` [configuration](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#cluster-setup). 
-1. Groups of vminserts B know about only vmstorages B and this is explicitly specified via `-storageNode` [configuration](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#cluster-setup). 
-1. Groups of vminserts C know about only vmstorages C and this is explicitly specified via `-storageNode` [configuration](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#cluster-setup). 
-1. vmselect reads data from all vmstorage nodes via `-storageNode` [configuration](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#cluster-setup) 
-   with [deduplication](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#deduplication) setting equal to vmagent's scrape interval or minimum interval between collected samples. 
-1. vmagent routes incoming metrics to the given set of `vminsert` nodes using relabeling rules specified at `-remoteWrite.urlRelabelConfig` [configuration](https://docs.victoriametrics.com/victoriametrics/relabeling/).
+- Group A: 3-month retention.
+- Group B: 1-year retention.
+- Group C: 3-year retention. 
 
-**Multi-Tenant Setup**
+Metrics are routed to the appropriate vminsert group by splitting data streams in vmagent, so each time series is sent to exactly one retention group instead of being replicated to all groups. See [Deploying vmagent](https://docs.victoriametrics.com/guides/guide-vmcluster-multiple-retention-setup/#step3) for an example of label‑based routing that implements this split. An optional [vmauth](https://docs.victoriametrics.com/guides/guide-vmcluster-multiple-retention-setup/#additional-enhancements) layer can be added on top to restrict access to specific sub‑clusters or tenants while still keeping a unified write and read path.
 
-Every group of vmstorages can handle one tenant or multiple one. Different groups can have overlapping tenants. As vmselect reads from all vmstorage nodes, the data is aggregated on its level.
+## Implementing Multi-Retention on Kubernetes
 
-**Additional Enhancements**
+In this section, we'll install and configure the components for a multi-retention deployment of the VictoriaMetrics cluster. See [Kubernetes monitoring with VictoriaMetrics Cluster](https://docs.victoriametrics.com/guides/k8s-monitoring-via-vm-cluster/) for details on running VictoriaMetrics in Kubernetes.
 
-You can set up [vmauth](https://docs.victoriametrics.com/victoriametrics/vmauth/) for routing data to the given vminsert group depending on the needed retention.
+Run the following command to add the VictoriaMetrics Helm repository:
+
+```shell
+helm repo add vm https://victoriametrics.github.io/helm-charts/
+helm repo update
+```
+
+### Step 1: Deploying storage groups {#step1}
+
+We'll create three storage groups. Each has a different retention period and disk size. Read [Understand Your Setup Size](https://docs.victoriametrics.com/guides/understand-your-setup-size/) to estimate how much space you will need for each group. The following table is shown as an example:
+
+
+| Group        | Retention Period | Total disk size       |
+|--------------|------------------|-----------------------|
+| `vmcluster-a`  | 3 months (`3M`)    | 80 Gi                 |
+| `vmcluster-b`  | 1 year (`1Y`)      | 300 Gi                |
+| `vmcluster-c`  | 3 years (`3Y`)     | 900 Gi                |
+
+Create a Helm values file for Group A.
+
+```shell
+cat <<EOF > vmcluster-a.yaml
+vmstorage:
+  enabled: true
+  replicaCount: 1
+  persistence:
+    size: 80Gi
+  extraArgs:
+    retentionPeriod: 3M
+  podLabels:
+    retention-group: a
+
+vminsert:
+  enabled: true
+  podLabels:
+    retention-group: a
+
+vmselect:
+  enabled: false
+EOF
+```
+
+The values file above creates vminsert and vmstorage services while turning off vmselect, which we'll deploy separately. The `retentionPeriod` flag configures how long data is kept in this group.
+
+Create the values files for Group B and Group C:
+
+```shell
+cat <<EOF > vmcluster-b.yaml
+vmstorage:
+  enabled: true
+  replicaCount: 1
+  persistence:
+    size: 300Gi
+  extraArgs:
+    retentionPeriod: 1y
+  podLabels:
+    retention-group: b
+
+vminsert:
+  enabled: true
+  podLabels:
+    retention-group: b
+
+vmselect:
+  enabled: false
+EOF
+
+
+cat <<EOF > vmcluster-c.yaml
+vmstorage:
+  enabled: true
+  replicaCount: 1
+  persistence:
+    size: 900Gi
+  extraArgs:
+    retentionPeriod: 3y
+  podLabels:
+    retention-group: c
+
+vminsert:
+  enabled: true
+  podLabels:
+    retention-group: c
+
+vmselect:
+  enabled: false
+EOF
+```
+
+Deploy the three storage groups with:
+
+```shell
+helm upgrade --install vmcluster-a vm/victoria-metrics-cluster -f vmcluster-a.yaml
+helm upgrade --install vmcluster-b vm/victoria-metrics-cluster -f vmcluster-b.yaml
+helm upgrade --install vmcluster-c vm/victoria-metrics-cluster -f vmcluster-c.yaml
+
+# Wait for all storage pods to be ready
+kubectl rollout status statefulset -l app.kubernetes.io/instance=vmcluster-a
+kubectl rollout status statefulset -l app.kubernetes.io/instance=vmcluster-b
+kubectl rollout status statefulset -l app.kubernetes.io/instance=vmcluster-c
+```
+
+### Step 2: Deploying vmselect {#step2}
+
+Next, we'll deploy a vmselect service to route queries to the storage groups.
+
+Create a Helm values file with:
+
+```shell
+cat <<EOF >vmselect.yaml
+vmstorage:
+  enabled: false
+
+vminsert:
+  enabled: false
+
+vmselect:
+  enabled: true
+  replicaCount: 1
+  suppressStorageFQDNsRender: true
+  extraArgs:
+    # Each list item is a single -storageNode flag. In this example, there is
+    # one vmstorage pod per retention group, so each entry contains a single host.
+    # If you run multiple pods per group, list them as comma-separated hosts
+    # in the same -storageNode value.
+    #
+    # The FQDN format is:
+    #   <pod>.<svc>.default.svc
+    # where pod = <release>-victoria-metrics-cluster-vmstorage-<N>
+    # and   svc = <release>-victoria-metrics-cluster-vmstorage
+    storageNode:
+      - "vmcluster-a-victoria-metrics-cluster-vmstorage-0.vmcluster-a-victoria-metrics-cluster-vmstorage.default.svc:8401"
+      - "vmcluster-b-victoria-metrics-cluster-vmstorage-0.vmcluster-b-victoria-metrics-cluster-vmstorage.default.svc:8401"
+      - "vmcluster-c-victoria-metrics-cluster-vmstorage-0.vmcluster-c-victoria-metrics-cluster-vmstorage.default.svc:8401"
+EOF
+```
+
+Let's break down the file above:
+
+- Deploys vmselect as a separate Helm release. 
+- Disables vminsert and vmstorage as these services were already deployed in Step 1.
+- `suppressStorageFQDNsRender: true` turns off automatic FQDN generation for storage nodes. By default, the Helm chart auto-generates `-storageNodes` flags, but since `vmstorage` has been disabled, we need to supply them manually in `extraArgs`.
+- In `extraArgs.storageNode:` we define the vmstorage endpoints for queries. On querying, vmselect merges results across all the specified vmstorages to provide a unified view of the data.
+
+Deploy the `vmselect` release with:
+
+```shell
+helm upgrade --install vmselect vm/victoria-metrics-cluster -f vmselect.yaml
+```
+
+### Step 3: Deploying vmagent {#step3}
+
+We'll use `vmagent` to route incoming metrics to the correct retention group. For example, we can use a `retention` label for mapping metrics to storage groups in the following way:
+
+| `retention` label | Storage Group |
+|-------------------|--------------|
+| `"3mo"`           | `vmcluster-a` |
+| `"1yr"`           | `vmcluster-b` |
+| `"3yr"`           | `vmcluster-c` |
+
+
+Create the values file for vmagent:
+
+```shell
+cat <<EOF >vmagent.yaml
+service:
+  enabled: true
+remoteWrite:
+  # Group A: receives metrics with retention="3mo"
+  - url: http://vmcluster-a-victoria-metrics-cluster-vminsert:8480/insert/0/prometheus/api/v1/write
+    urlRelabelConfig:
+      - if: '{retention="3mo"}'
+        action: keep
+  # Group B: receives metrics with retention="1yr"
+  - url: http://vmcluster-b-victoria-metrics-cluster-vminsert:8480/insert/0/prometheus/api/v1/write
+    urlRelabelConfig:
+      - if: '{retention="1yr"}'
+        action: keep
+  # Group C: receives metrics with retention="3yr"
+  - url: http://vmcluster-c-victoria-metrics-cluster-vminsert:8480/insert/0/prometheus/api/v1/write
+    urlRelabelConfig:
+      - if: '{retention="3yr"}'
+        action: keep
+EOF
+```
+
+> Metrics without a matching `retention` label are silently dropped by the `keep` rules. You must ensure that every metric is labeled, or use a different routing configuration.
+
+Now deploy the vmagent release:
+
+```shell
+helm upgrade --install vmagent vm/victoria-metrics-agent -f vmagent.yaml
+```
+
+Wait for vmagent to become ready:
+
+```shell
+kubectl rollout status deploy/vmagent-victoria-metrics-agent
+```
+
+### Step 4: Verification
+
+We can send test data to verify that the data is flowing to the correct storage group.
+
+First, port-forward vmagent and vmselect:
+
+```shell
+VMAGENT_SVC=$(kubectl get svc -l app.kubernetes.io/instance=vmagent -o jsonpath='{.items[0].metadata.name}')
+kubectl port-forward "svc/$VMAGENT_SVC" 8429 &
+
+VMSELECT_SVC=$(kubectl get svc -l app.kubernetes.io/instance=vmselect -o jsonpath='{.items[0].metadata.name}')
+kubectl port-forward "svc/$VMSELECT_SVC" 8481 &
+```
+
+Send test metrics directly to vmagent's HTTP endpoint to exercise all three retention labels:
+
+```shell
+POD=$(kubectl get pod -l app.kubernetes.io/instance=vmagent -o jsonpath='{.items[0].metadata.name}')
+
+for retention in 3mo 1yr 3yr; do
+  kubectl exec "$POD" -- wget -qO- --post-data="test_routing{retention=\"${retention}\"} 1.0" \
+    "http://127.0.0.1:8429/api/v1/import/prometheus"
+done
+```
+
+Query the data back from vmselect (it may take around 30-60 seconds for new data to be available for queries):
+
+```shell
+for retention in 3mo 1yr 3yr; do
+  echo "-> retention=${retention}"
+  curl -s "http://localhost:8481/select/0/prometheus/api/v1/query" \
+    --data-urlencode "query=test_routing{retention=\"${retention}\"}"
+  echo
+done
+```
+
+You can also check that vmagent is forwarding data to all three groups:
+
+```shell
+curl -s http://localhost:8429/metrics | grep vmagent_remotewrite_blocks_sent_total
+```
+
+Each `url="N:secret-url"` corresponds to one `remoteWrite` entry (N=1 for Group A, N=2 for Group B, N=3 for Group C). Non-zero values confirm data is flowing.
+
+## Alternative Routing by Existing Labels
+
+The example setup above relies on a synthetic `retention` label to exist in every incoming metric.
+
+If having a `retention` label in every metric isn't practical, you can, as an alternative, rely on existing labels to map data to the correct storage group.
+
+The following example configures vmagent to route metrics based on the `environment` and `team` labels:
+
+```yaml
+# vmagent.yaml
+remoteWrite:
+  # send dev and staging data to Group A
+  - url: "http://vmcluster-a-victoria-metrics-cluster-vminsert:8480/insert/0/prometheus/api/v1/write"
+    urlRelabelConfig:
+      - if: {environment=~"dev|staging"}
+        action: keep
+  # send prod data to Group B
+  - url: "http://vmcluster-b-victoria-metrics-cluster-vminsert:8480/insert/0/prometheus/api/v1/write"
+    urlRelabelConfig:
+      - if: {environment=~"prod|production"}
+        action: keep
+  # send data from Infra and SRE teams to Group C
+  - url: "http://vmcluster-c-victoria-metrics-cluster-vminsert:8480/insert/0/prometheus/api/v1/write"
+    urlRelabelConfig:
+      - if: {team=~"infra|sre"}
+        action: keep
+```
+
+> Metrics that do not match any of the `keep` rules are dropped in the configuration above.
+
+## Additional Enhancements
+
+You can set up [vmauth](https://docs.victoriametrics.com/victoriametrics/vmauth/) to route data to the specified vminsert group based on the required retention or to restrict which data different users can query.
+
+The following [`-auth.config`](https://docs.victoriametrics.com/victoriametrics/vmauth/#quick-start) example exposes the same vmselect backend via vmauth with two users using basic auth:
+
+- `admin`: can query **all** data across all retention groups.
+- `dev`: can query **only** time series that have `team="dev"` label, enforced via the `extra_label` query argument.
+
+```yaml
+users:
+  # User with access to all data across all retention groups
+  - username: "admin"
+    password: "foo"
+    url_map:
+      - src_paths:
+          - "/api/v1/query"
+          - "/api/v1/query_range"
+          - "/api/v1/series"
+          - "/api/v1/labels"
+          - "/api/v1/label/.+/values"
+        # vmselect service that aggregates all vmstorage groups
+        url_prefix: "http://vmselect-victoria-metrics-cluster-vmselect:8481/select/0/prometheus"
+
+  # User restricted to Dev team data only
+  - username: "dev"
+    password: "bar"
+    url_map:
+      - src_paths:
+          - "/api/v1/query"
+          - "/api/v1/query_range"
+          - "/api/v1/series"
+          - "/api/v1/labels"
+          - "/api/v1/label/.+/values"
+        # Same vmselect backend, but enforce label filter at query time
+        # by adding extra_label=team=dev to every proxied request
+        url_prefix: "http://vmselect-victoria-metrics-cluster-vmselect:8481/select/0/prometheus/?extra_label=team=dev"
+```
+
+This is useful for restricting access by team, environment, or tenant without changing the underlying storage topology.

docs/victoriametrics/changelog/CHANGELOG.md

@@ -26,7 +26,13 @@ See also [LTS releases](https://docs.victoriametrics.com/victoriametrics/lts-rel
 
 ## tip
 
-* BUGFIX: [stream aggregation](https://docs.victoriametrics.com/victoriametrics/stream-aggregation/): fix issue with producing aggregated samples with identical timestamps between flushes. See PR [#10808](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/10808) for details.
+* FEATURE: all VictoriaMetrics components: add `-http.header.disableServerHostname` command-line flag for disabling the `X-Server-Hostname` HTTP response header. See [#11067](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11067). Thanks to @zasdaym for contribution.
+* FEATURE: [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/) and `vmselect` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): log calls to [/api/v1/admin/tsdb/delete_series](https://docs.victoriametrics.com/victoriametrics/url-examples/#apiv1admintsdbdelete_series) API handler. This should help to identify events of metrics deletion from the database. See [#11104](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/11104).
+* FEATURE: [vmctl](https://docs.victoriametrics.com/victoriametrics/vmctl/): add `-vm-headers` and `-vm-bearer-token` flags for authenticating requests to the VictoriaMetrics import destination. The flags are available in `opentsdb`, `influx`, `remote-read`, `prometheus`, `mimir`, and `thanos` vmctl sub-commands. See [#8897](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/8897).
+* FEATURE: [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/): Add the support of vmselect RPC to vmsingle so that single node can be queried by a vmselect from a vmcluster deployment. See [4328](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4328) and [10926](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/10926).
+
+* BUGFIX: [stream aggregation](https://docs.victoriametrics.com/victoriametrics/stream-aggregation/): fix issue with producing aggregated samples with identical timestamps between flushes. See [#10808](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/10808).
+* BUGFIX: [vmbackup](https://docs.victoriametrics.com/vmbackup/), [vmbackupmanager](https://docs.victoriametrics.com/victoriametrics/vmbackupmanager/): do not fail backup list if directory is absent while using `fs://` destination to align with other protocols. See [6c3c548](https://github.com/VictoriaMetrics/VictoriaMetrics/commit/6c3c548ddb0385b749e731f52276f130e2a4e4a8)
 
 ## [v1.145.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.145.0)
 

docs/victoriametrics/victoria_metrics_common_flags.md

@@ -95,6 +95,8 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string
@@ -621,7 +623,7 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/
   -version
      Show VictoriaMetrics version
   -vmalert.proxyURL string
-     Optional URL for proxying requests to vmalert. For example, if -vmalert.proxyURL=http://vmalert:8880 , then alerting API requests such as /api/v1/rules from Grafana will be proxied to http://vmalert:8880/api/v1/rules
+     Optional URL for proxying requests to vmalert. For example, if -vmalert.proxyURL=http://vmalert:8880 , then alerting API requests such as /api/v1/rules from Grafana will be proxied to http://vmalert:8880/api/v1/rules . See https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#vmalert
   -vmui.customDashboardsPath string
      Optional path to vmui dashboards. See https://github.com/VictoriaMetrics/VictoriaMetrics/tree/master/app/vmui/packages/vmui/public/dashboards
   -vmui.defaultTimezone string

docs/victoriametrics/vmagent_common_flags.md

@@ -74,6 +74,8 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/vmagent/ .
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vmalert_common_flags.md

@@ -115,6 +115,8 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/vmalert/ .
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vmauth_common_flags.md

@@ -59,6 +59,8 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/vmauth/ .
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vmbackup.md

@@ -400,6 +400,8 @@ Run `vmbackup -help` in order to see all the available options:
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vmbackupmanager.md

@@ -575,6 +575,8 @@ command-line flags:
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vmgateway.md

@@ -496,6 +496,8 @@ Below is the list of configuration flags (it can be viewed by running `./vmgatew
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vminsert_common_flags.md

@@ -76,6 +76,8 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/cluster-victori
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vmrestore.md

@@ -102,6 +102,8 @@ Run `vmrestore -help` in order to see all the available options:
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

docs/victoriametrics/vmselect_common_flags.md

@@ -75,6 +75,8 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/cluster-victori
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string
@@ -323,7 +325,7 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/cluster-victori
   -version
      Show VictoriaMetrics version
   -vmalert.proxyURL string
-     Optional URL for proxying requests to vmalert. For example, if -vmalert.proxyURL=http://vmalert:8880 , then alerting API requests such as /api/v1/rules from Grafana will be proxied to http://vmalert:8880/api/v1/rules
+     Optional URL for proxying requests to vmalert. For example, if -vmalert.proxyURL=http://vmalert:8880 , then alerting API requests such as /api/v1/rules from Grafana will be proxied to http://vmalert:8880/api/v1/rules . See https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/#vmalert
   -vmstorageDialTimeout duration
      Timeout for establishing RPC connections from vmselect to vmstorage. See also -vmstorageUserTimeout (default 3s)
   -vmstorageUserTimeout duration

docs/victoriametrics/vmstorage_common_flags.md

@@ -68,6 +68,8 @@ See the docs at https://docs.victoriametrics.com/victoriametrics/cluster-victori
      Disable compression of HTTP responses to save CPU resources. By default, compression is enabled to save network bandwidth
   -http.header.csp string
      Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"
+  -http.header.disableServerHostname
+     Whether to disable 'X-Server-Hostname' header in HTTP responses
   -http.header.frameOptions string
      Value for 'X-Frame-Options' header
   -http.header.hsts string

lib/handshake/buffered_conn.go

@@ -0,0 +1,140 @@
+package handshake
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"time"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding/zstd"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fasttime"
+)
+
+type bufferedWriter interface {
+	Write(p []byte) (int, error)
+	Flush() error
+}
+
+// BufferedConn is a net.Conn with Flush suport.
+type BufferedConn struct {
+	net.Conn
+
+	// IsLegacy defines if BufferedConn operates in legacy mode
+	// and doesn't support RPC protocol
+	IsLegacy bool
+
+	br io.Reader
+	bw bufferedWriter
+
+	readDeadline  time.Time
+	writeDeadline time.Time
+}
+
+const bufferSize = 64 * 1024
+
+// newBufferedConn returns buffered connection with the given compression level.
+func newBufferedConn(c net.Conn, compressionLevel int, isReadCompressed bool) *BufferedConn {
+	bc := &BufferedConn{
+		Conn: c,
+	}
+	if compressionLevel <= 0 {
+		bc.bw = bufio.NewWriterSize(c, bufferSize)
+	} else {
+		bc.bw = zstd.NewWriterLevel(c, compressionLevel)
+	}
+	if !isReadCompressed {
+		bc.br = bufio.NewReaderSize(c, bufferSize)
+	} else {
+		bc.br = zstd.NewReader(c)
+	}
+	return bc
+}
+
+// SetDeadline sets read and write deadlines for bc to t.
+//
+// Deadline is checked on each Read and Write call.
+func (bc *BufferedConn) SetDeadline(t time.Time) error {
+	bc.readDeadline = t
+	bc.writeDeadline = t
+	return bc.Conn.SetDeadline(t)
+}
+
+// SetReadDeadline sets read deadline for bc to t.
+//
+// Deadline is checked on each Read call.
+func (bc *BufferedConn) SetReadDeadline(t time.Time) error {
+	bc.readDeadline = t
+	return bc.Conn.SetReadDeadline(t)
+}
+
+// SetWriteDeadline sets write deadline for bc to t.
+//
+// Deadline is checked on each Write call.
+func (bc *BufferedConn) SetWriteDeadline(t time.Time) error {
+	bc.writeDeadline = t
+	return bc.Conn.SetWriteDeadline(t)
+}
+
+// Read reads up to len(p) from bc to p.
+func (bc *BufferedConn) Read(p []byte) (int, error) {
+	startTime := fasttime.UnixTimestamp()
+	if deadlineExceeded(bc.readDeadline, startTime) {
+		return 0, os.ErrDeadlineExceeded
+	}
+	n, err := bc.br.Read(p)
+	if err != nil && err != io.EOF {
+		err = fmt.Errorf("cannot read data in %d seconds: %w", fasttime.UnixTimestamp()-startTime, err)
+	}
+	return n, err
+}
+
+// Write writes p to bc.
+//
+// Do not forget to call Flush if needed.
+func (bc *BufferedConn) Write(p []byte) (int, error) {
+	startTime := fasttime.UnixTimestamp()
+	if deadlineExceeded(bc.writeDeadline, startTime) {
+		return 0, os.ErrDeadlineExceeded
+	}
+	n, err := bc.bw.Write(p)
+	if err != nil {
+		err = fmt.Errorf("cannot write data in %d seconds: %w", fasttime.UnixTimestamp()-startTime, err)
+	}
+	return n, err
+}
+
+func deadlineExceeded(deadline time.Time, currentTimestamp uint64) bool {
+	if deadline.IsZero() {
+		return false
+	}
+	return currentTimestamp > uint64(deadline.Unix())
+}
+
+// Close closes bc.
+func (bc *BufferedConn) Close() error {
+	// Close the Conn at first. It is expected that all the required data
+	// is already flushed to the Conn.
+	err := bc.Conn.Close()
+	bc.Conn = nil
+
+	if zr, ok := bc.br.(*zstd.Reader); ok {
+		zr.Release()
+	}
+	bc.br = nil
+
+	if zw, ok := bc.bw.(*zstd.Writer); ok {
+		// Do not call zw.Close(), since we already closed the underlying conn.
+		zw.Release()
+	}
+	bc.bw = nil
+
+	bc.IsLegacy = false
+	return err
+}
+
+// Flush flushes internal write buffers to the underlying conn.
+func (bc *BufferedConn) Flush() error {
+	return bc.bw.Flush()
+}

lib/handshake/handshake.go

@@ -0,0 +1,318 @@
+package handshake
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
+)
+
+var rpcHandshakeTimeout = flag.Duration("rpc.handshakeTimeout", 5*time.Second, "Timeout for RPC handshake between vminsert/vmselect and vmstorage. Increase this value if transient handshake failures occur. See https://docs.victoriametrics.com/victoriametrics/troubleshooting/#cluster-instability section for more details.")
+
+const (
+	vminsertHelloLegacyVersion = "vminsert.02"
+	vminsertHello              = "vminsert.03"
+	vmselectHello              = "vmselect.01"
+
+	successResponse = "ok"
+)
+
+// Func must perform handshake on the given c using the given compressionLevel.
+//
+// It must return BufferedConn wrapper for c on successful handshake.
+type Func func(c net.Conn, compressionLevel int) (*BufferedConn, error)
+
+// VMInsertClientWithDialer performs client-side handshake for vminsert protocol.
+//
+// it uses provided dial func to establish connection to the server.
+// compressionLevel is a legacy option which defines the level used for compression of the data sent
+// to the server.
+// compressionLevel <= 0 means 'no compression'
+func VMInsertClientWithDialer(dial func() (net.Conn, error), compressionLevel int) (*BufferedConn, error) {
+	c, err := dial()
+	if err != nil {
+		return nil, fmt.Errorf("dial error: %w", err)
+	}
+	bc, err := vminsertClient(c, 0)
+	if err == nil {
+		return bc, nil
+	}
+	_ = c.Close()
+	if !strings.Contains(err.Error(), "cannot read success response after sending hello") {
+		return nil, err
+	}
+	// try to fallback to the prev non-RPC API version
+	// we cannot re-use exist connection, since vmstorage already closed it
+	c, err = dial()
+	if err != nil {
+		return nil, fmt.Errorf("dial error: %w", err)
+	}
+	bc, err = genericClient(c, vminsertHelloLegacyVersion, compressionLevel)
+	if err != nil {
+		_ = c.Close()
+		return nil, fmt.Errorf("legacy handshake error: %w", err)
+	}
+	bc.IsLegacy = true
+	logger.Infof("server=%q doesn't support new RPC version, fallback to the legacy format", c.RemoteAddr())
+	return bc, nil
+}
+
+func vminsertClient(c net.Conn, compressionLevel int) (*BufferedConn, error) {
+	return genericClient(c, vminsertHello, compressionLevel)
+}
+
+// VMInsertClientWithHello performs client-side handshake for vminsert protocol.
+//
+// should be used for testing only
+func VMInsertClientWithHello(c net.Conn, helloMsg string, compressionLevel int) (*BufferedConn, error) {
+	return genericClient(c, helloMsg, compressionLevel)
+}
+
+// VMInsertServer performs server-side handshake for vminsert protocol.
+//
+// compressionLevel is the level used for compression of the data sent
+// to the client.
+// compressionLevel <= 0 means 'no compression'
+func VMInsertServer(c net.Conn, compressionLevel int) (*BufferedConn, error) {
+
+	var isRPCSupported bool
+	bc, err := genericServer(c, compressionLevel, func(c net.Conn) error {
+		buf, err := readData(c, len(vminsertHello))
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// This is likely a TCP healthcheck, which must be ignored in order to prevent logs pollution.
+				// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1762
+				return errTCPHealthcheck
+			}
+			return fmt.Errorf("cannot read hello: %w", err)
+		}
+		isRPCSupported = string(buf) == vminsertHello
+		if !isRPCSupported {
+			// try to fallback to the previous protocol version
+			if string(buf) != vminsertHelloLegacyVersion {
+				return fmt.Errorf("unexpected message obtained; got %q; want %q", buf, vminsertHello)
+			}
+			logger.Infof("client=%q doesn't support new RPC version, fallback to the legacy format", c.RemoteAddr())
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	bc.IsLegacy = !isRPCSupported
+	return bc, nil
+}
+
+// VMInsertServerWithLegacyHello performs server-side handshake for vminsert protocol
+// with legacy hello  message
+//
+// should be used for testing only
+func VMInsertServerWithLegacyHello(c net.Conn, compressionLevel int) (*BufferedConn, error) {
+
+	bc, err := genericServer(c, compressionLevel, func(c net.Conn) error {
+		return readMessage(c, vminsertHelloLegacyVersion)
+	})
+	if err != nil {
+		return nil, err
+	}
+	bc.IsLegacy = true
+	return bc, nil
+}
+
+// VMSelectClient performs client-side handshake for vmselect protocol.
+//
+// compressionLevel is the level used for compression of the data sent
+// to the server.
+// compressionLevel <= 0 means 'no compression'
+func VMSelectClient(c net.Conn, compressionLevel int) (*BufferedConn, error) {
+	return genericClient(c, vmselectHello, compressionLevel)
+}
+
+// VMSelectServer performs server-side handshake for vmselect protocol.
+//
+// compressionLevel is the level used for compression of the data sent
+// to the client.
+// compressionLevel <= 0 means 'no compression'
+func VMSelectServer(c net.Conn, compressionLevel int) (*BufferedConn, error) {
+	return genericServer(c, compressionLevel, func(c net.Conn) error {
+		err := readMessage(c, vmselectHello)
+		if errors.Is(err, io.EOF) {
+			// This is likely a TCP healthcheck, which must be ignored in order to prevent logs pollution.
+			// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1762 and https://github.com/VictoriaMetrics/VictoriaMetrics/issues/10786
+			return errTCPHealthcheck
+		}
+		return err
+	})
+}
+
+// errTCPHealthcheck indicates that the connection was opened as part of a TCP health check
+// and was closed immediately after being established.
+//
+// This is expected behavior and can be safely ignored.
+var errTCPHealthcheck = fmt.Errorf("TCP health check connection – safe to ignore")
+
+// IsTCPHealthcheck determines whether the provided error is a TCP health check
+func IsTCPHealthcheck(err error) bool {
+	return errors.Is(err, errTCPHealthcheck)
+}
+
+// IsClientNetworkError determines whether the provided error is a client-side network error,
+// such as io.EOF, io.ErrUnexpectedEOF, or a timeout.
+// These errors typically occur when a client disconnects abruptly or fails during the handshake,
+// and are generally non-actionable from the server point of view.
+// This function helps distinguish such errors from critical ones during the handshake process
+// and adjust logging accordingly.
+//
+// See: https://github.com/VictoriaMetrics/VictoriaMetrics-enterprise/pull/880
+func IsClientNetworkError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
+		return true
+	}
+
+	if IsTimeoutNetworkError(err) {
+		return true
+	}
+
+	if errMsg := err.Error(); strings.Contains(errMsg, "broken pipe") || strings.Contains(errMsg, "reset by peer") {
+		return true
+	}
+
+	return false
+}
+
+// IsTimeoutNetworkError determines whether the provided error is a network error with a timeout.
+func IsTimeoutNetworkError(err error) bool {
+	var ne net.Error
+	if errors.As(err, &ne) && ne.Timeout() {
+		return true
+	}
+
+	return false
+}
+
+func genericServer(c net.Conn, compressionLevel int, readHelloMessage func(c net.Conn) error) (*BufferedConn, error) {
+	if err := c.SetDeadline(time.Now().Add(*rpcHandshakeTimeout)); err != nil {
+		return nil, fmt.Errorf("cannot set deadline: %w", err)
+	}
+
+	if err := readHelloMessage(c); err != nil {
+		return nil, fmt.Errorf("cannot read hello message : %w", err)
+	}
+	if err := writeMessage(c, successResponse); err != nil {
+		return nil, fmt.Errorf("cannot write success response on isCompressed: %w", err)
+	}
+	isRemoteCompressed, err := readIsCompressed(c)
+	if err != nil {
+		return nil, fmt.Errorf("cannot read isCompressed flag: %w", err)
+	}
+	if err := writeMessage(c, successResponse); err != nil {
+		return nil, fmt.Errorf("cannot write success response on isCompressed: %w", err)
+	}
+	if err := writeIsCompressed(c, compressionLevel > 0); err != nil {
+		return nil, fmt.Errorf("cannot write isCompressed flag: %w", err)
+	}
+	if err := readMessage(c, successResponse); err != nil {
+		return nil, fmt.Errorf("cannot read success response on isCompressed: %w", err)
+	}
+
+	if err := c.SetDeadline(time.Time{}); err != nil {
+		return nil, fmt.Errorf("cannot reset deadline: %w", err)
+	}
+
+	bc := newBufferedConn(c, compressionLevel, isRemoteCompressed)
+	return bc, nil
+}
+
+func genericClient(c net.Conn, msg string, compressionLevel int) (*BufferedConn, error) {
+	if err := c.SetDeadline(time.Now().Add(*rpcHandshakeTimeout)); err != nil {
+		return nil, fmt.Errorf("cannot set deadline: %w", err)
+	}
+
+	if err := writeMessage(c, msg); err != nil {
+		return nil, fmt.Errorf("cannot write hello: %w", err)
+	}
+	if err := readMessage(c, successResponse); err != nil {
+		return nil, fmt.Errorf("cannot read success response after sending hello: %w", err)
+	}
+	if err := writeIsCompressed(c, compressionLevel > 0); err != nil {
+		return nil, fmt.Errorf("cannot write isCompressed flag: %w", err)
+	}
+	if err := readMessage(c, successResponse); err != nil {
+		return nil, fmt.Errorf("cannot read success response on isCompressed: %w", err)
+	}
+	isRemoteCompressed, err := readIsCompressed(c)
+	if err != nil {
+		return nil, fmt.Errorf("cannot read isCompressed flag: %w", err)
+	}
+	if err := writeMessage(c, successResponse); err != nil {
+		return nil, fmt.Errorf("cannot write success response on isCompressed: %w", err)
+	}
+
+	if err := c.SetDeadline(time.Time{}); err != nil {
+		return nil, fmt.Errorf("cannot reset deadline: %w", err)
+	}
+
+	bc := newBufferedConn(c, compressionLevel, isRemoteCompressed)
+	return bc, nil
+}
+
+func writeIsCompressed(c net.Conn, isCompressed bool) error {
+	var buf [1]byte
+	if isCompressed {
+		buf[0] = 1
+	}
+	return writeMessage(c, string(buf[:]))
+}
+
+func readIsCompressed(c net.Conn) (bool, error) {
+	buf, err := readData(c, 1)
+	if err != nil {
+		return false, err
+	}
+	isCompressed := buf[0] != 0
+	return isCompressed, nil
+}
+
+func writeMessage(c net.Conn, msg string) error {
+	if _, err := io.WriteString(c, msg); err != nil {
+		return fmt.Errorf("cannot write %q to server: %w", msg, err)
+	}
+	if fc, ok := c.(flusher); ok {
+		if err := fc.Flush(); err != nil {
+			return fmt.Errorf("cannot flush %q to server: %w", msg, err)
+		}
+	}
+	return nil
+}
+
+type flusher interface {
+	Flush() error
+}
+
+func readMessage(c net.Conn, msg string) error {
+	buf, err := readData(c, len(msg))
+	if err != nil {
+		return err
+	}
+	if string(buf) != msg {
+		return fmt.Errorf("unexpected message obtained; got %q; want %q", buf, msg)
+	}
+	return nil
+}
+
+func readData(c net.Conn, dataLen int) ([]byte, error) {
+	data := make([]byte, dataLen)
+	if n, err := io.ReadFull(c, data); err != nil {
+		return nil, fmt.Errorf("cannot read message with size %d: %w; read only %d bytes", dataLen, err, n)
+	}
+	return data, nil
+}

lib/handshake/handshake_test.go

@@ -0,0 +1,83 @@
+package handshake
+
+import (
+	"fmt"
+	"net"
+	"testing"
+	"time"
+)
+
+func TestVMInsertHandshake(t *testing.T) {
+	testHandshake(t, vminsertClient, VMInsertServer)
+}
+
+func TestVMSelectHandshake(t *testing.T) {
+	testHandshake(t, VMSelectClient, VMSelectServer)
+}
+
+func TestVMSelectServerTCPHealthcheck(t *testing.T) {
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("cannot start listener: %s", err)
+	}
+
+	c, err := net.Dial("tcp", ln.Addr().String())
+	if err != nil {
+		t.Fatalf("cannot dial: %s", err)
+	}
+	if err := c.Close(); err != nil {
+		t.Fatalf("cannot close client conn: %s", err)
+	}
+	s, err := ln.Accept()
+	if err != nil {
+		t.Fatalf("cannot accept conn: %s", err)
+	}
+	if _, err := VMSelectServer(s, 0); !IsTCPHealthcheck(err) {
+		t.Fatalf("unexpected error; got %v; want TCP healthcheck error", err)
+	}
+}
+
+func testHandshake(t *testing.T, clientFunc, serverFunc Func) {
+	t.Helper()
+
+	c, s := net.Pipe()
+	ch := make(chan error, 1)
+	go func() {
+		bcs, err := serverFunc(s, 3)
+		if err != nil {
+			ch <- fmt.Errorf("error on outer handshake: %w", err)
+			return
+		}
+		bcc, err := clientFunc(bcs, 3)
+		if err != nil {
+			ch <- fmt.Errorf("error on inner handshake: %w", err)
+			return
+		}
+		if bcc == nil {
+			ch <- fmt.Errorf("expecting non-nil conn")
+			return
+		}
+		ch <- nil
+	}()
+
+	bcc, err := clientFunc(c, 0)
+	if err != nil {
+		t.Fatalf("error on outer handshake: %s", err)
+	}
+	bcs, err := serverFunc(bcc, 0)
+	if err != nil {
+		t.Fatalf("error on inner handshake: %s", err)
+	}
+	if bcs == nil {
+		t.Fatalf("expecting non-nil conn")
+	}
+
+	select {
+	case <-time.After(5 * time.Second):
+		t.Fatalf("timeout")
+	case err := <-ch:
+		if err != nil {
+			t.Fatalf("unexpected error on the server side: %s", err)
+		}
+	}
+}

lib/httpserver/httpserver.go

@@ -64,9 +64,10 @@ var (
 	connTimeout                 = flag.Duration("http.connTimeout", 2*time.Minute, "Incoming connections to -httpListenAddr are closed after the configured timeout. "+
 		"This may help evenly spreading load among a cluster of services behind TCP-level load balancer. Zero value disables closing of incoming connections")
 
-	headerHSTS         = flag.String("http.header.hsts", "", "Value for 'Strict-Transport-Security' header, recommended: 'max-age=31536000; includeSubDomains'")
-	headerFrameOptions = flag.String("http.header.frameOptions", "", "Value for 'X-Frame-Options' header")
-	headerCSP          = flag.String("http.header.csp", "", `Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"`)
+	headerHSTS                  = flag.String("http.header.hsts", "", "Value for 'Strict-Transport-Security' header, recommended: 'max-age=31536000; includeSubDomains'")
+	headerFrameOptions          = flag.String("http.header.frameOptions", "", "Value for 'X-Frame-Options' header")
+	headerCSP                   = flag.String("http.header.csp", "", `Value for 'Content-Security-Policy' header, recommended: "default-src 'self'"`)
+	headerDisableServerHostname = flag.Bool("http.header.disableServerHostname", false, "Whether to disable 'X-Server-Hostname' header in HTTP responses")
 
 	disableCORS = flag.Bool("http.disableCORS", false, `Disable CORS for all origins (*)`)
 )
@@ -329,7 +330,9 @@ func handlerWrapper(w http.ResponseWriter, r *http.Request, rh RequestHandler) {
 	if *headerCSP != "" {
 		h.Add("Content-Security-Policy", *headerCSP)
 	}
-	h.Add("X-Server-Hostname", hostname)
+	if !*headerDisableServerHostname {
+		h.Add("X-Server-Hostname", hostname)
+	}
 	requestsTotal.Inc()
 	if whetherToCloseConn(r) {
 		connTimeoutClosedConns.Inc()

lib/httpserver/httpserver_test.go

@@ -228,4 +228,30 @@ func TestHandlerWrapper(t *testing.T) {
 	if got := h.Get("Content-Security-Policy"); got != cspHeader {
 		t.Fatalf("unexpected CSP header; got %q; want %q", got, cspHeader)
 	}
+	if got := h.Get("X-Server-Hostname"); got != hostname {
+		t.Fatalf("unexpected X-Server-Hostname header; got %q; want %q", got, hostname)
+	}
+}
+
+func TestHandlerWrapperDisableServerHostnameHeader(t *testing.T) {
+	origDisableServerHostname := *headerDisableServerHostname
+	*headerDisableServerHostname = true
+	defer func() {
+		*headerDisableServerHostname = origDisableServerHostname
+	}()
+
+	req, _ := http.NewRequest("GET", "/health", nil)
+
+	srv := &server{s: &http.Server{}}
+	w := &httptest.ResponseRecorder{}
+
+	handlerWrapper(w, req, func(w http.ResponseWriter, r *http.Request) bool {
+		return builtinRoutesHandler(srv, r, w, func(_ http.ResponseWriter, _ *http.Request) bool {
+			return true
+		})
+	})
+
+	if got := w.Header().Get("X-Server-Hostname"); got != "" {
+		t.Fatalf("unexpected X-Server-Hostname header; got %q; want empty value", got)
+	}
 }

lib/httputil/time_test.go

@@ -52,6 +52,9 @@ func TestGetTimeSuccess(t *testing.T) {
 	f("292277025-08-18T07:12:54.999999999Z", maxTimeMsecs)
 	f("1562529662.324", 1562529662324)
 	f("1223372036.855", 1223372036855)
+
+	// relative duration that resolves to a timestamp before 1970
+	f("-9223372036.854", minTimeMsecs)
 }
 
 func TestGetTimeError(t *testing.T) {
@@ -63,8 +66,8 @@ func TestGetTimeError(t *testing.T) {
 			t.Fatalf("unexpected error in NewRequest: %s", err)
 		}
 
-		if _, err := GetTime(r, "s", 123); err == nil {
-			t.Fatalf("expecting non-nil error in GetTime(%q)", s)
+		if msec, err := GetTime(r, "s", 123); err == nil {
+			t.Fatalf("expecting non-nil error in GetTime(%q); got %d", s, msec)
 		}
 	}
 
@@ -84,7 +87,6 @@ func TestGetTimeError(t *testing.T) {
 	f("123md")
 	f("-12.3md")
 
-	// relative duration that resolves to a timestamp before 1970
-	f("-9223372036.854")
+	// relative duration outside the allowed range
 	f("-9223372036.855")
 }

lib/storage/search.go

@@ -325,6 +325,17 @@ func (s *Search) NextMetricBlock() bool {
 
 // SearchQuery is used for sending search queries from vmselect to vmstorage.
 type SearchQuery struct {
+	AccountID uint32
+	ProjectID uint32
+
+	// TenantTokens and IsMultiTenant is artificial fields
+	// they're only exist at runtime and cannot be transferred
+	// via network calls for keeping communication protocol compatibility
+	// TODO:@f41gh7 introduce breaking change to the protocol later
+	// and use TenantTokens instead of AccountID and ProjectID
+	TenantTokens  []TenantToken
+	IsMultiTenant bool
+
 	// The time range for searching time series
 	MinTimestamp int64
 	MaxTimestamp int64
@@ -468,15 +479,30 @@ func (tf *TagFilter) Unmarshal(src []byte) ([]byte, error) {
 	return src, nil
 }
 
-// String returns string representation of the search query.
+// String returns string representation of the search query: tag filters and time range.
 func (sq *SearchQuery) String() string {
+	start := TimestampToHumanReadableFormat(sq.MinTimestamp)
+	end := TimestampToHumanReadableFormat(sq.MaxTimestamp)
+	a := sq.FiltersString()
+	if !sq.IsMultiTenant {
+		return fmt.Sprintf("accountID=%d, projectID=%d, filters=%s, timeRange=[%s..%s]", sq.AccountID, sq.ProjectID, a, start, end)
+	}
+	tts := make([]string, len(sq.TenantTokens))
+	for i, tt := range sq.TenantTokens {
+		tts[i] = tt.String()
+	}
+
+	return fmt.Sprintf("tenants=[%s], filters=%s, timeRange=[%s..%s]", strings.Join(tts, ","), a, start, end)
+
+}
+
+// FiltersString returns string representation of the tag filters.
+func (sq *SearchQuery) FiltersString() []string {
 	a := make([]string, len(sq.TagFilterss))
 	for i, tfs := range sq.TagFilterss {
 		a[i] = tagFiltersToString(tfs)
 	}
-	start := TimestampToHumanReadableFormat(sq.MinTimestamp)
-	end := TimestampToHumanReadableFormat(sq.MaxTimestamp)
-	return fmt.Sprintf("filters=%s, timeRange=[%s..%s]", a, start, end)
+	return a
 }
 
 func tagFiltersToString(tfs []TagFilter) string {
@@ -487,8 +513,9 @@ func tagFiltersToString(tfs []TagFilter) string {
 	return "{" + strings.Join(a, ",") + "}"
 }
 
-// Marshal appends marshaled sq to dst and returns the result.
-func (sq *SearchQuery) Marshal(dst []byte) []byte {
+// MarshalWithoutTenant appends marshaled sq without AccountID/ProjectID to dst and returns the result.
+// It is expected that TenantToken is already marshaled to dst.
+func (sq *SearchQuery) MarshalWithoutTenant(dst []byte) []byte {
 	dst = encoding.MarshalVarInt64(dst, sq.MinTimestamp)
 	dst = encoding.MarshalVarInt64(dst, sq.MaxTimestamp)
 	dst = encoding.MarshalVarUint64(dst, uint64(len(sq.TagFilterss)))
@@ -498,11 +525,25 @@ func (sq *SearchQuery) Marshal(dst []byte) []byte {
 			dst = tagFilters[i].Marshal(dst)
 		}
 	}
+	dst = encoding.MarshalUint32(dst, uint32(sq.MaxMetrics))
 	return dst
 }
 
 // Unmarshal unmarshals sq from src and returns the tail.
 func (sq *SearchQuery) Unmarshal(src []byte) ([]byte, error) {
+	if len(src) < 4 {
+		return src, fmt.Errorf("cannot unmarshal AccountID: too short src len: %d; must be at least %d bytes", len(src), 4)
+	}
+	sq.AccountID = encoding.UnmarshalUint32(src)
+	src = src[4:]
+
+	if len(src) < 4 {
+		return src, fmt.Errorf("cannot unmarshal ProjectID: too short src len: %d; must be at least %d bytes", len(src), 4)
+	}
+	sq.ProjectID = encoding.UnmarshalUint32(src)
+	src = src[4:]
+
+	sq.TenantTokens = []TenantToken{{AccountID: sq.AccountID, ProjectID: sq.ProjectID}}
 	minTs, nSize := encoding.UnmarshalVarInt64(src)
 	if nSize <= 0 {
 		return src, fmt.Errorf("cannot unmarshal MinTimestamp from varint")
@@ -543,6 +584,12 @@ func (sq *SearchQuery) Unmarshal(src []byte) ([]byte, error) {
 		sq.TagFilterss[i] = tagFilters
 	}
 
+	if len(src) < 4 {
+		return src, fmt.Errorf("cannot unmarshal MaxMetrics: too short src len: %d; must be at least %d bytes", len(src), 4)
+	}
+	sq.MaxMetrics = int(encoding.UnmarshalUint32(src))
+	src = src[4:]
+
 	return src, nil
 }
 

lib/storage/search_test.go

@@ -32,7 +32,12 @@ func TestSearchQueryMarshalUnmarshal(t *testing.T) {
 			// Skip nil sq1.
 			continue
 		}
-		buf = sq1.Marshal(buf[:0])
+		tt := TenantToken{
+			AccountID: sq1.AccountID,
+			ProjectID: sq1.ProjectID,
+		}
+		buf = tt.Marshal(buf[:0])
+		buf = sq1.MarshalWithoutTenant(buf)
 
 		tail, err := sq2.Unmarshal(buf)
 		if err != nil {
@@ -41,6 +46,12 @@ func TestSearchQueryMarshalUnmarshal(t *testing.T) {
 		if len(tail) > 0 {
 			t.Fatalf("unexpected tail left after SearchQuery unmarshaling; tail (len=%d): %q", len(tail), tail)
 		}
+		if sq2.AccountID != sq1.AccountID {
+			t.Fatalf("unexpected AccountID; got %d; want %d", sq2.AccountID, sq1.AccountID)
+		}
+		if sq2.ProjectID != sq1.ProjectID {
+			t.Fatalf("unexpected ProjectID; got %d; want %d", sq2.ProjectID, sq1.ProjectID)
+		}
 		if sq1.MinTimestamp != sq2.MinTimestamp {
 			t.Fatalf("unexpected MinTimestamp; got %d; want %d", sq2.MinTimestamp, sq1.MinTimestamp)
 		}

lib/streamaggr/histogram_bucket.go

@@ -14,16 +14,10 @@ func (av *histogramBucketAggrValue) pushSample(_ aggrConfig, sample *pushSample,
 	av.h.Update(sample.value)
 }
 
-func (av *histogramBucketAggrValue) flush(c aggrConfig, ctx *flushCtx, key string, _ bool) {
-	ac := c.(*histogramBucketAggrConfig)
-	shared := av.shared
-	if ac.useSharedState {
-		shared.Merge(&av.h)
-		av.h.Reset()
-	} else {
-		shared = &av.h
-	}
-	shared.VisitNonZeroBuckets(func(vmrange string, count uint64) {
+func (av *histogramBucketAggrValue) flush(_ aggrConfig, ctx *flushCtx, key string, _ bool) {
+	av.shared.Merge(&av.h)
+	av.h.Reset()
+	av.shared.VisitNonZeroBuckets(func(vmrange string, count uint64) {
 		ctx.appendSeriesWithExtraLabel(key, "histogram_bucket", float64(count), "vmrange", vmrange)
 	})
 }
@@ -32,26 +26,17 @@ func (av *histogramBucketAggrValue) state() any {
 	return av.shared
 }
 
-func newHistogramBucketAggrConfig(useSharedState bool) aggrConfig {
-	return &histogramBucketAggrConfig{
-		useSharedState: useSharedState,
-	}
+func newHistogramBucketAggrConfig() aggrConfig {
+	return &histogramBucketAggrConfig{}
 }
 
-type histogramBucketAggrConfig struct {
-	useSharedState bool
-}
+type histogramBucketAggrConfig struct{}
 
-func (ac *histogramBucketAggrConfig) getValue(s any) aggrValue {
-	var shared *metrics.Histogram
-	if ac.useSharedState {
-		if s == nil {
-			shared = &metrics.Histogram{}
-		} else {
-			shared = s.(*metrics.Histogram)
-		}
+func (*histogramBucketAggrConfig) getValue(s any) aggrValue {
+	if s == nil {
+		s = &metrics.Histogram{}
 	}
 	return &histogramBucketAggrValue{
-		shared: shared,
+		shared: s.(*metrics.Histogram),
 	}
 }

lib/streamaggr/increase.go

@@ -0,0 +1,109 @@
+package streamaggr
+
+import (
+	"fmt"
+
+	"github.com/VictoriaMetrics/metrics"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fasttime"
+)
+
+type increaseLastValue struct {
+	value          float64
+	timestamp      int64
+	deleteDeadline int64
+}
+
+type increaseAggrConfig struct {
+	keepFirstSample bool
+
+	// The first sample per each new series is ignored until this unix timestamp deadline in seconds even if keepFirstSample is set.
+	// This allows avoiding an initial spike of the output values at startup when new time series
+	// cannot be distinguished from already existing series. This is tracked with ignoreFirstSampleDeadline.
+	ignoreFirstSampleDeadline uint64
+	counterResetsTotal        *metrics.Counter
+}
+
+type increaseAggrValue struct {
+	total  *float64
+	shared map[string]increaseLastValue
+}
+
+func (av *increaseAggrValue) pushSample(c aggrConfig, sample *pushSample, key string, deleteDeadline int64) {
+	ac := c.(*increaseAggrConfig)
+	currentTime := fasttime.UnixTimestamp()
+	keepFirstSample := ac.keepFirstSample && currentTime >= ac.ignoreFirstSampleDeadline
+	lv, ok := av.shared[key]
+	if av.total == nil {
+		av.total = new(float64)
+	}
+	if ok {
+		if sample.timestamp < lv.timestamp {
+			// Skip out of order sample
+			return
+		}
+		if sample.value >= lv.value {
+			*av.total += sample.value - lv.value
+		} else {
+			// counter reset
+			*av.total += sample.value
+			ac.counterResetsTotal.Inc()
+		}
+	} else if keepFirstSample {
+		*av.total += sample.value
+	}
+	lv.value = sample.value
+	lv.timestamp = sample.timestamp
+	lv.deleteDeadline = deleteDeadline
+	key = bytesutil.InternString(key)
+	av.shared[key] = lv
+}
+
+func (av *increaseAggrValue) flush(c aggrConfig, ctx *flushCtx, key string, isLast bool) {
+	ac := c.(*increaseAggrConfig)
+	for lk, lv := range av.shared {
+		if ctx.flushTimestamp > lv.deleteDeadline || isLast {
+			delete(av.shared, lk)
+		}
+	}
+	if av.total == nil {
+		return
+	}
+	total := *av.total
+	av.total = nil
+	ctx.appendSeries(key, ac.getSuffix(), total)
+}
+
+func (av *increaseAggrValue) state() any {
+	return av.shared
+}
+
+func newIncreaseAggrConfig(ms *metrics.Set, metricLabels string, ignoreFirstSampleIntervalSecs uint64, keepFirstSample bool) aggrConfig {
+	ignoreFirstSampleDeadline := fasttime.UnixTimestamp() + ignoreFirstSampleIntervalSecs
+	cfg := &increaseAggrConfig{
+		keepFirstSample:           keepFirstSample,
+		ignoreFirstSampleDeadline: ignoreFirstSampleDeadline,
+	}
+	cfg.counterResetsTotal = ms.NewCounter(fmt.Sprintf(`vm_streamaggr_counter_resets_total{%s}`, metricLabels))
+	return cfg
+}
+
+func (*increaseAggrConfig) getValue(s any) aggrValue {
+	var shared map[string]increaseLastValue
+	if s == nil {
+		shared = make(map[string]increaseLastValue)
+	} else {
+		shared = s.(map[string]increaseLastValue)
+	}
+	return &increaseAggrValue{
+		shared: shared,
+	}
+}
+
+func (ac *increaseAggrConfig) getSuffix() string {
+	if ac.keepFirstSample {
+		return "increase"
+	}
+	return "increase_prometheus"
+}

lib/streamaggr/output.go

@@ -75,6 +75,9 @@ func (ao *aggrOutputs) pushSamples(samples []pushSample, deleteDeadline int64, i
 				outputs = av.blue
 			}
 			for idx, o := range outputs {
+				if o == nil {
+					o = av.blue[idx]
+				}
 				o.pushSample(ao.configs[idx], sample, inputKey, deleteDeadline)
 			}
 			av.deleteDeadline = deleteDeadline
@@ -112,6 +115,9 @@ func (ao *aggrOutputs) flushState(ctx *flushCtx) {
 			outputs = av.blue
 		}
 		for i, o := range outputs {
+			if o == nil {
+				o = av.blue[i]
+			}
 			o.flush(ao.configs[i], ctx, outputKey, ctx.isLast)
 		}
 		av.mu.Unlock()

lib/streamaggr/streamaggr.go

@@ -609,7 +609,7 @@ func newAggregator(cfg *Config, path string, pushFunc PushFunc, ms *metrics.Set,
 	outputsSeen := make(map[string]struct{}, len(cfg.Outputs))
 	for i, output := range cfg.Outputs {
 		outputMetricLabels := fmt.Sprintf(`output=%q,name=%q,path=%q,url=%q,position="%d"`, output, name, path, alias, aggrID)
-		ac, err := newOutputConfig(ms, outputMetricLabels, output, outputsSeen, useSharedState, ignoreFirstSampleInterval)
+		ac, err := newOutputConfig(ms, outputMetricLabels, output, outputsSeen, ignoreFirstSampleInterval)
 		if err != nil {
 			return nil, err
 		}
@@ -716,7 +716,7 @@ func newAggregator(cfg *Config, path string, pushFunc PushFunc, ms *metrics.Set,
 	return a, nil
 }
 
-func newOutputConfig(ms *metrics.Set, metricLabels, output string, outputsSeen map[string]struct{}, useSharedState bool, ignoreFirstSampleInterval time.Duration) (aggrConfig, error) {
+func newOutputConfig(ms *metrics.Set, metricLabels, output string, outputsSeen map[string]struct{}, ignoreFirstSampleInterval time.Duration) (aggrConfig, error) {
 	// check for duplicated output
 	if _, ok := outputsSeen[output]; ok {
 		return nil, fmt.Errorf("`outputs` list contains duplicate aggregation function: %s", output)
@@ -760,11 +760,11 @@ func newOutputConfig(ms *metrics.Set, metricLabels, output string, outputsSeen m
 	case "count_series":
 		return newCountSeriesAggrConfig(), nil
 	case "histogram_bucket":
-		return newHistogramBucketAggrConfig(useSharedState), nil
+		return newHistogramBucketAggrConfig(), nil
 	case "increase":
-		return newTotalAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, true, true), nil
+		return newIncreaseAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, true), nil
 	case "increase_prometheus":
-		return newTotalAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, true, false), nil
+		return newIncreaseAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, false), nil
 	case "last":
 		return newLastAggrConfig(), nil
 	case "max":
@@ -782,9 +782,9 @@ func newOutputConfig(ms *metrics.Set, metricLabels, output string, outputsSeen m
 	case "sum_samples":
 		return newSumSamplesAggrConfig(), nil
 	case "total":
-		return newTotalAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, false, true), nil
+		return newTotalAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, true), nil
 	case "total_prometheus":
-		return newTotalAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, false, false), nil
+		return newTotalAggrConfig(ms, metricLabels, ignoreFirstSampleIntervalSecs, false), nil
 	case "unique_samples":
 		return newUniqueSamplesAggrConfig(), nil
 	default:

lib/streamaggr/total.go

@@ -53,36 +53,30 @@ func (av *totalAggrValue) pushSample(c aggrConfig, sample *pushSample, key strin
 
 func (av *totalAggrValue) flush(c aggrConfig, ctx *flushCtx, key string, isLast bool) {
 	ac := c.(*totalAggrConfig)
-	suffix := ac.getSuffix()
-	// check for stale entries
 	total := av.shared.total + av.total
 	av.total = 0
-	lvs := av.shared.lastValues
-	for lk, lv := range lvs {
+	for lk, lv := range av.shared.lastValues {
 		if ctx.flushTimestamp > lv.deleteDeadline || isLast {
-			delete(lvs, lk)
+			delete(av.shared.lastValues, lk)
 		}
 	}
-	if ac.resetTotalOnFlush {
-		av.shared.total = 0
-	} else if math.Abs(total) >= (1 << 53) {
+	if math.Abs(total) >= (1 << 53) {
 		// It is time to reset the entry, since it starts losing float64 precision
 		av.shared.total = 0
 	} else {
 		av.shared.total = total
 	}
-	ctx.appendSeries(key, suffix, total)
+	ctx.appendSeries(key, ac.getSuffix(), total)
 }
 
 func (av *totalAggrValue) state() any {
 	return av.shared
 }
 
-func newTotalAggrConfig(ms *metrics.Set, metricLabels string, ignoreFirstSampleIntervalSecs uint64, resetTotalOnFlush, keepFirstSample bool) aggrConfig {
+func newTotalAggrConfig(ms *metrics.Set, metricLabels string, ignoreFirstSampleIntervalSecs uint64, keepFirstSample bool) aggrConfig {
 	ignoreFirstSampleDeadline := fasttime.UnixTimestamp() + ignoreFirstSampleIntervalSecs
 	cfg := &totalAggrConfig{
 		keepFirstSample:           keepFirstSample,
-		resetTotalOnFlush:         resetTotalOnFlush,
 		ignoreFirstSampleDeadline: ignoreFirstSampleDeadline,
 	}
 	cfg.counterResetsTotal = ms.NewCounter(fmt.Sprintf(`vm_streamaggr_counter_resets_total{%s}`, metricLabels))
@@ -90,8 +84,6 @@ func newTotalAggrConfig(ms *metrics.Set, metricLabels string, ignoreFirstSampleI
 }
 
 type totalAggrConfig struct {
-	resetTotalOnFlush bool
-
 	// Whether to take into account the first sample in new time series when calculating the output value.
 	keepFirstSample bool
 
@@ -117,12 +109,6 @@ func (*totalAggrConfig) getValue(s any) aggrValue {
 }
 
 func (ac *totalAggrConfig) getSuffix() string {
-	if ac.resetTotalOnFlush {
-		if ac.keepFirstSample {
-			return "increase"
-		}
-		return "increase_prometheus"
-	}
 	if ac.keepFirstSample {
 		return "total"
 	}

lib/timeutil/duration.go

@@ -19,7 +19,7 @@ func ParseDuration(s string) (time.Duration, error) {
 		return 0, err
 	}
 	if ms < minValidMilli || maxValidMilli < ms {
-		return 0, fmt.Errorf("duration %q must be in the range [%v, %v]", s, minDuration, maxDuration)
+		return 0, fmt.Errorf("duration %q must be in the range [%s, %s]", s, minDuration, maxDuration)
 	}
 	return time.Duration(ms) * time.Millisecond, nil
 }

lib/timeutil/time.go

@@ -28,7 +28,6 @@ func ParseTimeMsec(s string) (int64, error) {
 // See https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/#timestamp-formats
 //
 // If s doesn't contain timezone information, then the local timezone is used.
-// The time must be in the range [1970-01-01T00:00:00Z, 2262-04-11T23:47:16Z].
 //
 // It returns unix timestamp in nanoseconds.
 func ParseTimeAt(s string, currentTimestamp int64) (int64, error) {
@@ -71,14 +70,10 @@ func ParseTimeAt(s string, currentTimestamp int64) (int64, error) {
 		if err != nil {
 			return 0, err
 		}
-		if d > 0 {
+		if d < 0 {
 			d = -d
 		}
-		nsec := currentTimestamp + int64(d)
-		if nsec < 0 {
-			return 0, fmt.Errorf("time %s (%v) must be in the range [%v, %v]", sOrig, time.Unix(0, nsec).UTC(), minTime, maxTime)
-		}
-		return nsec, nil
+		return subInt64NoOverflow(currentTimestamp, int64(d)), nil
 	}
 	if len(s) == 4 {
 		// Parse YYYY
@@ -115,22 +110,28 @@ func ParseTimeAt(s string, currentTimestamp int64) (int64, error) {
 	return parseTimeAt(time.RFC3339, sOrig, 0, sOrig)
 }
 
-var (
-	minTime = time.Unix(0, 0).UTC()
-	maxTime = time.Unix(0, math.MaxInt64).UTC()
-)
-
-func parseTimeAt(layout, value string, tzOffsetNanos int64, sOrig string) (int64, error) {
+func parseTimeAt(layout, value string, tzOffsetNsec int64, sOrig string) (int64, error) {
 	t, err := time.Parse(layout, value)
 	if err != nil {
 		return 0, err
 	}
-	tzOffset := time.Duration(tzOffsetNanos)
-	t = t.UTC().Add(tzOffset)
-	if t.Before(minTime) || t.After(maxTime) {
-		return 0, fmt.Errorf("time %s (%v) must be in the range [%v, %v]", sOrig, t, minTime, maxTime)
+	nsec := t.UnixNano()
+
+	return subInt64NoOverflow(nsec, -tzOffsetNsec), nil
+}
+
+func subInt64NoOverflow(a, b int64) int64 {
+	if b >= 0 {
+		if a < math.MinInt64+b {
+			return math.MinInt64
+		}
+		return a - b
 	}
-	return t.UnixNano(), nil
+
+	if a > math.MaxInt64+b {
+		return math.MaxInt64
+	}
+	return a - b
 }
 
 // TryParseUnixTimestamp parses s as unix timestamp in seconds, milliseconds, microseconds or nanoseconds and returns the parsed timestamp in nanoseconds.

lib/timeutil/time_test.go

@@ -210,6 +210,7 @@ func TestParseTimeAtLimits(t *testing.T) {
 
 	f := func(s string, wantTime time.Time) {
 		t.Helper()
+
 		got, err := ParseTimeAt(s, now.UnixNano())
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
@@ -231,42 +232,38 @@ func TestParseTimeAtLimits(t *testing.T) {
 	west := location(t, "Etc/GMT+12") // UTC-12:00
 	var s string
 
-	// min timestamp
-	f("0", time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	s = fmt.Sprintf("-%d", now.Unix())
-	f(s, time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	s = fmt.Sprintf("now-%d", now.Unix())
-	f(s, time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-
 	// min year
-	f("1970Z", time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	f("1971+14:00", time.Date(1971, 1, 1, 0, 0, 0, 0, east))
-	f("1970-12:00", time.Date(1970, 1, 1, 0, 0, 0, 0, west))
+	f("1678Z", time.Date(1678, 1, 1, 0, 0, 0, 0, time.UTC))
+	f("1678+14:00", time.Date(1678, 1, 1, 0, 0, 0, 0, east))
+	f("1678-12:00", time.Date(1678, 1, 1, 0, 0, 0, 0, west))
 
 	// min month
-	f("1970-01Z", time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	f("1970-02+14:00", time.Date(1970, 2, 1, 0, 0, 0, 0, east))
-	f("1970-01-12:00", time.Date(1970, 1, 1, 0, 0, 0, 0, west))
+	f("1677-10Z", time.Date(1677, 10, 1, 0, 0, 0, 0, time.UTC))
+	f("1677-10+14:00", time.Date(1677, 10, 1, 0, 0, 0, 0, east))
+	f("1677-10-12:00", time.Date(1677, 10, 1, 0, 0, 0, 0, west))
 
 	// min day
-	f("1970-01-01Z", time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	f("1970-01-02+14:00", time.Date(1970, 1, 2, 0, 0, 0, 0, east))
-	f("1970-01-01-12:00", time.Date(1970, 1, 1, 0, 0, 0, 0, west))
+	f("1677-09-22Z", time.Date(1677, 9, 22, 0, 0, 0, 0, time.UTC))
+	f("1677-09-22+14:00", time.Date(1677, 9, 22, 0, 0, 0, 0, east))
+	f("1677-09-22-12:00", time.Date(1677, 9, 22, 0, 0, 0, 0, west))
 
 	// min hour
-	f("1970-01-01T00Z", time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	f("1970-01-01T14+14:00", time.Date(1970, 1, 1, 14, 0, 0, 0, east))
-	f("1969-12-31T12-12:00", time.Date(1969, 12, 31, 12, 0, 0, 0, west))
+	f("1677-09-21T01Z", time.Date(1677, 9, 21, 1, 0, 0, 0, time.UTC))
+	f("1677-09-21T15+14:00", time.Date(1677, 9, 21, 15, 0, 0, 0, east))
+	f("1677-09-21T01+14:00", time.Unix(0, math.MinInt64))
+	f("1677-09-21T01-12:00", time.Date(1677, 9, 21, 1, 0, 0, 0, west))
 
 	// min minute
-	f("1970-01-01T00:00Z", time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	f("1970-01-01T14:00+14:00", time.Date(1970, 1, 1, 14, 0, 0, 0, east))
-	f("1969-12-31T12:00-12:00", time.Date(1969, 12, 31, 12, 0, 0, 0, west))
+	f("1677-09-21T00:12Z", time.Date(1677, 9, 21, 0, 12, 0, 0, time.UTC))
+	f("1677-09-21T15:12Z+14:00", time.Date(1677, 9, 21, 15, 12, 0, 0, east))
+	f("1677-09-21T00:13Z+14:00", time.Unix(0, math.MinInt64))
+	f("1677-09-21T00:13Z-12:00", time.Date(1677, 9, 21, 0, 13, 0, 0, west))
 
 	// min second
-	f("1970-01-01T00:00:00Z", time.Date(1970, 1, 1, 0, 0, 0, 0, time.UTC))
-	f("1970-01-01T14:00:00+14:00", time.Date(1970, 1, 1, 14, 0, 0, 0, east))
-	f("1969-12-31T12:00:00-12:00", time.Date(1969, 12, 31, 12, 0, 0, 0, west))
+	f("1677-09-21T00:12:43Z", time.Date(1677, 9, 21, 0, 12, 43, 0, time.UTC))
+	f("1677-09-21T15:12:43Z+14:00", time.Date(1677, 9, 21, 15, 12, 43, 0, east))
+	f("1677-09-21T00:12:44Z+14:00", time.Unix(0, math.MinInt64))
+	f("1677-09-21T00:12:44Z-12:00", time.Date(1677, 9, 21, 0, 12, 44, 0, west))
 
 	// max year
 	f("2262Z", time.Date(2262, 1, 1, 0, 0, 0, 0, time.UTC))
@@ -280,23 +277,26 @@ func TestParseTimeAtLimits(t *testing.T) {
 
 	// max day
 	f("2262-04-11Z", time.Date(2262, 4, 11, 0, 0, 0, 0, time.UTC))
-	f("2262-04-12+14:00", time.Date(2262, 4, 12, 0, 0, 0, 0, east))
+	f("2262-04-11+14:00", time.Date(2262, 4, 11, 0, 0, 0, 0, east))
 	f("2262-04-11-12:00", time.Date(2262, 4, 11, 0, 0, 0, 0, west))
 
 	// max hour
 	f("2262-04-11T23Z", time.Date(2262, 4, 11, 23, 0, 0, 0, time.UTC))
-	f("2262-04-12T13+14:00", time.Date(2262, 4, 12, 13, 0, 0, 0, east))
+	f("2262-04-11T23+14:00", time.Date(2262, 4, 11, 23, 0, 0, 0, east))
 	f("2262-04-11T11-12:00", time.Date(2262, 4, 11, 11, 0, 0, 0, west))
+	f("2262-04-11T23-12:00", time.Unix(0, math.MaxInt64))
 
 	// max minute
 	f("2262-04-11T23:47Z", time.Date(2262, 4, 11, 23, 47, 0, 0, time.UTC))
-	f("2262-04-12T13:47+14:00", time.Date(2262, 4, 12, 13, 47, 0, 0, east))
+	f("2262-04-11T23:47+14:00", time.Date(2262, 4, 11, 23, 47, 0, 0, east))
 	f("2262-04-11T11:47-12:00", time.Date(2262, 4, 11, 11, 47, 0, 0, west))
+	f("2262-04-11T23:47-12:00", time.Unix(0, math.MaxInt64))
 
 	// max second
 	f("2262-04-11T23:47:16Z", time.Date(2262, 4, 11, 23, 47, 16, 0, time.UTC))
-	f("2262-04-12T13:47:16+14:00", time.Date(2262, 4, 12, 13, 47, 16, 0, east))
+	f("2262-04-11T23:47:16+14:00", time.Date(2262, 4, 11, 23, 47, 16, 0, east))
 	f("2262-04-11T11:47:16-12:00", time.Date(2262, 4, 11, 11, 47, 16, 0, west))
+	f("2262-04-11T23:47:16-12:00", time.Unix(0, math.MaxInt64))
 
 	// max timestamp
 	s = fmt.Sprintf("%d", int64(maxValidSecond))
@@ -324,85 +324,6 @@ func TestParseTimeAtLimits(t *testing.T) {
 	f(s, time.Date(1970, 4, 17, 18, 2, 52, 36_854_776, time.UTC))
 }
 
-func TestParseTimeAtOutsideLimits(t *testing.T) {
-	now := time.Date(2025, 1, 1, 0, 0, 0, 0, time.UTC)
-
-	f := func(s string) {
-		t.Helper()
-		got, err := ParseTimeAt(s, now.UnixNano())
-		if err == nil {
-			t.Fatalf("expected error but got %d", got)
-		}
-		if !strings.Contains(err.Error(), "must be in the range") {
-			t.Fatalf("expected error: %v", err)
-		}
-	}
-
-	// min timestamp
-	f(fmt.Sprintf("-%d", now.Unix()+1))
-	f(fmt.Sprintf("now-%d", now.Unix()+1))
-
-	// min year
-	f("1969Z")
-	f("1970+14:00")
-	f("1969-12:00")
-
-	// min month
-	f("1969-12Z")
-	f("1970-01+14:00")
-	f("1969-12-12:00")
-
-	// min day
-	f("1969-12-31Z")
-	f("1970-01-01+14:00")
-	f("1969-12-31-12:00")
-
-	// min hour
-	f("1969-12-31T23Z")
-	f("1970-01-01T13+14:00")
-	f("1969-12-31T11-12:00")
-
-	// min minute
-	f("1969-12-31T23:59Z")
-	f("1970-01-01T13:59+14:00")
-	f("1969-12-31T11:59-12:00")
-
-	// min second
-	f("1969-12-31T23:59:59Z")
-	f("1970-01-01T13:59:59+14:00")
-	f("1969-12-31T11:59:59-12:00")
-
-	// max year
-	f("2263Z")
-	f("2263+14:00")
-	f("2263-12:00")
-
-	// max month
-	f("2262-05Z")
-	f("2262-05+14:00")
-	f("2262-05-12:00")
-
-	// max day
-	f("2262-04-12Z")
-	f("2262-04-13+14:00")
-	f("2262-04-12-12:00")
-
-	// max hour
-	f("2262-04-12T00Z")
-	f("2262-04-12T14+14:00")
-	f("2262-04-11T12-12:00")
-
-	// max minute
-	f("2262-04-11T23:48Z")
-	f("2262-04-12T13:48+14:00")
-	f("2262-04-11T11:48-12:00")
-
-	// max second
-	f("2262-04-11T23:47:17Z")
-	f("2262-04-12T13:47:17+14:00")
-	f("2262-04-11T11:47:17-12:00")
-}
-
 func TestParseTimeAtOutsideLimits_Nanos(t *testing.T) {
 	now := time.Date(2025, 1, 1, 0, 0, 0, 0, time.UTC)
 
@@ -434,7 +355,6 @@ func TestParseTimeMsecFailure(t *testing.T) {
 	}
 
 	f("")
-	f("2263")
 	f("23-45:50")
 	f("1223-fo:ba")
 	f("1223-12:ba")

lib/vmalertproxy/vmalertproxy.go

@@ -0,0 +1,68 @@
+package vmalertproxy
+
+import (
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"strings"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
+)
+
+// Init initializes proxying requests to the given proxyURL when calling HandleRequest.
+//
+// Init must be called after flag.Parse(), since it uses command-line flags.
+func Init(proxyURL string) {
+	if len(proxyURL) == 0 {
+		return
+	}
+	pu, err := url.Parse(proxyURL)
+	if err != nil {
+		logger.Fatalf("cannot parse -vmalert.proxyURL=%q: %s", proxyURL, err)
+	}
+	vmalertProxyHost = pu.Host
+	vmalertProxy = httputil.NewSingleHostReverseProxy(pu)
+}
+
+// HandleRequest proxies the given request path to vmalert at proxyURL passed to Init().
+func HandleRequest(w http.ResponseWriter, r *http.Request, path string) {
+	defer func() {
+		err := recover()
+		if err == nil || err == http.ErrAbortHandler {
+			// Suppress http.ErrAbortHandler panic.
+			// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1353
+			return
+		}
+		// Forward other panics to the caller.
+		panic(err)
+	}()
+	req := r.Clone(r.Context())
+	req.URL.Path = path
+	req.Host = vmalertProxyHost
+
+	if strings.HasPrefix(r.Header.Get(`User-Agent`), `Grafana`) {
+		// Grafana currently supports only Prometheus-style alerts. If other alert types
+		// (e.g. logs or traces) are returned, it may fail with "Error loading alerts".
+		//
+		// Grafana queries the vmalert API directly, bypassing the VictoriaMetrics datasource,
+		// so query params (such as datasource_type) cannot be enforced on the Grafana side.
+		//
+		// To ensure compatibility, we detect Grafana requests via the User-Agent and enforce
+		// `datasource_type=prometheus`.
+		//
+		// See:
+		// - https://github.com/VictoriaMetrics/victoriametrics-datasource/issues/329#issuecomment-3847585443
+		// - https://github.com/VictoriaMetrics/victoriametrics-datasource/issues/59
+		q := req.URL.Query()
+		q.Set("datasource_type", "prometheus")
+		req.URL.RawQuery = q.Encode()
+		req.RequestURI = ""
+	}
+
+	vmalertProxy.ServeHTTP(w, req)
+}
+
+var (
+	vmalertProxyHost string
+	vmalertProxy     *httputil.ReverseProxy
+)