vmselect: add support of multi-tenant queries (#6346)

### Describe Your Changes

Added an ability to query data across multiple tenants. See:
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1434

Currently, the following endpoints work with multi-tenancy:
- /prometheus/api/v1/query
- /prometheus/api/v1/query_range
- /prometheus/api/v1/series
- /prometheus/api/v1/labels
- /prometheus/api/v1/label/<label_name>/values
- /prometheus/api/v1/status/active_queries
- /prometheus/api/v1/status/top_queries
- /prometheus/api/v1/status/tsdb
- /prometheus/api/v1/export
- /prometheus/api/v1/export/csv
- /vmui


A note regarding VMUI: endpoints such as `active_queries` and
`top_queries` have been updated to indicate whether query was a
single-tenant or multi-tenant, but UI needs to be updated to display
this info.
cc: @Loori-R 

---------

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Signed-off-by: f41gh7 <nik@victoriametrics.com>
Co-authored-by: f41gh7 <nik@victoriametrics.com>

app/vmselect/main.go

@@ -11,6 +11,8 @@ import (
 	"strings"
 	"time"
 
+	"github.com/VictoriaMetrics/metrics"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/clusternative"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/graphite"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/netstorage"
@@ -34,7 +36,6 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/tenantmetrics"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/vmselectapi"
-	"github.com/VictoriaMetrics/metrics"
 )
 
 var (
@@ -268,7 +269,7 @@ func requestHandler(w http.ResponseWriter, r *http.Request) bool {
 		httpserver.Errorf(w, r, "cannot parse path %q: %s", path, err)
 		return true
 	}
-	at, err := auth.NewToken(p.AuthToken)
+	at, err := auth.NewTokenPossibleMultitenant(p.AuthToken)
 	if err != nil {
 		httpserver.Errorf(w, r, "auth error: %s", err)
 		return true
@@ -309,6 +310,10 @@ func selectHandler(qt *querytracer.Tracer, startTime time.Time, w http.ResponseW
 			return true
 		}
 	}
+	if strings.HasPrefix(p.Suffix, "graphite/") && at == nil {
+		httpserver.Errorf(w, r, "multi-tenant queries are not supported by Graphite endpoints")
+		return true
+	}
 	if strings.HasPrefix(p.Suffix, "graphite/tags/") && !isGraphiteTagsPath(p.Suffix[len("graphite"):]) {
 		tagName := p.Suffix[len("graphite/tags/"):]
 		graphiteTagValuesRequests.Inc()
@@ -651,7 +656,7 @@ func handleStaticAndSimpleRequests(w http.ResponseWriter, r *http.Request, path
 	}
 	switch p.Suffix {
 	case "prometheus/api/v1/status/active_queries":
-		at, err := auth.NewToken(p.AuthToken)
+		at, err := auth.NewTokenPossibleMultitenant(p.AuthToken)
 		if err != nil {
 			return false
 		}
@@ -660,7 +665,7 @@ func handleStaticAndSimpleRequests(w http.ResponseWriter, r *http.Request, path
 		promql.ActiveQueriesHandler(at, w, r)
 		return true
 	case "prometheus/api/v1/status/top_queries":
-		at, err := auth.NewToken(p.AuthToken)
+		at, err := auth.NewTokenPossibleMultitenant(p.AuthToken)
 		if err != nil {
 			return false
 		}

app/vmselect/netstorage/netstorage.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"os"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -79,8 +80,9 @@ func (r *Result) reset() {
 
 // Results holds results returned from ProcessSearchQuery.
 type Results struct {
-	tr       storage.TimeRange
-	deadline searchutils.Deadline
+	shouldConvertTenantToLabels bool
+	tr                          storage.TimeRange
+	deadline                    searchutils.Deadline
 
 	tbfs []*tmpBlocksFile
 
@@ -265,14 +267,24 @@ func (rss *Results) runParallel(qt *querytracer.Tracer, f func(rs *Result, worke
 		// Nothing to process
 		return 0, nil
 	}
-
+	cb := f
+	if rss.shouldConvertTenantToLabels {
+		cb = func(rs *Result, workerID uint) error {
+			// TODO: (@f41gh7) if labels duplicates will be fixed
+			// query will return Duplicate Output Series error
+			// in this case, TenantToTags must be moved into RegisterAndWriteBlock method
+			metricNameTenantToTags(&rs.MetricName)
+			return f(rs, workerID)
+		}
+	}
 	var mustStop atomic.Bool
 	initTimeseriesWork := func(tsw *timeseriesWork, pts *packedTimeseries) {
 		tsw.rss = rss
 		tsw.pts = pts
-		tsw.f = f
+		tsw.f = cb
 		tsw.mustStop = &mustStop
 	}
+
 	maxWorkers := MaxWorkers()
 	if maxWorkers == 1 || tswsLen == 1 {
 		// It is faster to process time series in the current goroutine.
@@ -834,7 +846,6 @@ func RegisterMetricNames(qt *querytracer.Tracer, mrs []storage.MetricRow, deadli
 func DeleteSeries(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline searchutils.Deadline) (int, error) {
 	qt = qt.NewChild("delete series: %s", sq)
 	defer qt.Done()
-	requestData := sq.Marshal(nil)
 
 	// Send the query to all the storage nodes in parallel.
 	type nodeResult struct {
@@ -843,25 +854,36 @@ func DeleteSeries(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline sear
 	}
 	sns := getStorageNodes()
 	snr := startStorageNodesRequest(qt, sns, true, func(qt *querytracer.Tracer, _ uint, sn *storageNode) any {
-		sn.deleteSeriesRequests.Inc()
-		deletedCount, err := sn.deleteSeries(qt, requestData, deadline)
+		err := populateSqTenantTokensIfNeeded(sq)
 		if err != nil {
-			sn.deleteSeriesErrors.Inc()
-		}
-		return &nodeResult{
-			deletedCount: deletedCount,
-			err:          err,
+			return []*nodeResult{{
+				err: err,
+			}}
 		}
+
+		return execSearchQuery(qt, sq, func(qt *querytracer.Tracer, requestData []byte, _ storage.TenantToken) any {
+			sn.deleteSeriesRequests.Inc()
+			deletedCount, err := sn.deleteSeries(qt, requestData, deadline)
+			if err != nil {
+				sn.deleteSeriesErrors.Inc()
+			}
+			return &nodeResult{
+				deletedCount: deletedCount,
+				err:          err,
+			}
+		})
 	})
 
 	// Collect results
 	deletedTotal := 0
 	err := snr.collectAllResults(func(result any) error {
-		nr := result.(*nodeResult)
-		if nr.err != nil {
-			return nr.err
+		for _, cr := range result.([]any) {
+			nr := cr.(*nodeResult)
+			if nr.err != nil {
+				return nr.err
+			}
+			deletedTotal += nr.deletedCount
 		}
-		deletedTotal += nr.deletedCount
 		return nil
 	})
 	if err != nil {
@@ -877,7 +899,6 @@ func LabelNames(qt *querytracer.Tracer, denyPartialResponse bool, sq *storage.Se
 	if deadline.Exceeded() {
 		return nil, false, fmt.Errorf("timeout exceeded before starting the query processing: %s", deadline.String())
 	}
-	requestData := sq.Marshal(nil)
 	// Send the query to all the storage nodes in parallel.
 	type nodeResult struct {
 		labelNames []string
@@ -885,28 +906,43 @@ func LabelNames(qt *querytracer.Tracer, denyPartialResponse bool, sq *storage.Se
 	}
 	sns := getStorageNodes()
 	snr := startStorageNodesRequest(qt, sns, denyPartialResponse, func(qt *querytracer.Tracer, _ uint, sn *storageNode) any {
-		sn.labelNamesRequests.Inc()
-		labelNames, err := sn.getLabelNames(qt, requestData, maxLabelNames, deadline)
+		err := populateSqTenantTokensIfNeeded(sq)
 		if err != nil {
-			sn.labelNamesErrors.Inc()
-			err = fmt.Errorf("cannot get labels from vmstorage %s: %w", sn.connPool.Addr(), err)
-		}
-		return &nodeResult{
-			labelNames: labelNames,
-			err:        err,
+			return []*nodeResult{{
+				err: err,
+			}}
 		}
+
+		return execSearchQuery(qt, sq, func(qt *querytracer.Tracer, requestData []byte, _ storage.TenantToken) any {
+			sn.labelNamesRequests.Inc()
+			labelNames, err := sn.getLabelNames(qt, requestData, maxLabelNames, deadline)
+			if err != nil {
+				sn.labelNamesErrors.Inc()
+				err = fmt.Errorf("cannot get labels from vmstorage %s: %w", sn.connPool.Addr(), err)
+			}
+			return &nodeResult{
+				labelNames: labelNames,
+				err:        err,
+			}
+		})
 	})
 
 	// Collect results
 	var labelNames []string
 	isPartial, err := snr.collectResults(partialLabelNamesResults, func(result any) error {
-		nr := result.(*nodeResult)
-		if nr.err != nil {
-			return nr.err
+		for _, cr := range result.([]any) {
+			nr := cr.(*nodeResult)
+			if nr.err != nil {
+				return nr.err
+			}
+			labelNames = append(labelNames, nr.labelNames...)
 		}
-		labelNames = append(labelNames, nr.labelNames...)
+
 		return nil
 	})
+	if sq.IsMultiTenant {
+		labelNames = append(labelNames, []string{"vm_account_id", "vm_project_id"}...)
+	}
 	qt.Printf("get %d non-duplicated labels", len(labelNames))
 	if err != nil {
 		return nil, isPartial, fmt.Errorf("cannot fetch labels from vmstorage nodes: %w", err)
@@ -979,7 +1015,36 @@ func LabelValues(qt *querytracer.Tracer, denyPartialResponse bool, labelName str
 	if deadline.Exceeded() {
 		return nil, false, fmt.Errorf("timeout exceeded before starting the query processing: %s", deadline.String())
 	}
-	requestData := sq.Marshal(nil)
+
+	if sq.IsMultiTenant && isTenancyLabel(labelName) {
+		tenants, err := Tenants(qt, sq.GetTimeRange(), deadline)
+		if err != nil {
+			return nil, false, err
+		}
+
+		var idx int
+		switch labelName {
+		case "vm_account_id":
+			idx = 0
+		case "vm_project_id":
+			idx = 1
+		default:
+			logger.Fatalf("BUG: unexpected labeName=%q", labelName)
+		}
+
+		labelValues := make([]string, 0, len(tenants))
+		for _, t := range tenants {
+			s := strings.Split(t, ":")
+			if len(s) != 2 {
+				logger.Fatalf("BUG: unexpected tenant received from storage: %q", t)
+			}
+
+			labelValues = append(labelValues, s[idx])
+		}
+
+		labelValues = prepareLabelValues(qt, labelValues, maxLabelValues)
+		return labelValues, false, nil
+	}
 
 	// Send the query to all the storage nodes in parallel.
 	type nodeResult struct {
@@ -988,33 +1053,49 @@ func LabelValues(qt *querytracer.Tracer, denyPartialResponse bool, labelName str
 	}
 	sns := getStorageNodes()
 	snr := startStorageNodesRequest(qt, sns, denyPartialResponse, func(qt *querytracer.Tracer, _ uint, sn *storageNode) any {
-		sn.labelValuesRequests.Inc()
-		labelValues, err := sn.getLabelValues(qt, labelName, requestData, maxLabelValues, deadline)
+		err := populateSqTenantTokensIfNeeded(sq)
 		if err != nil {
-			sn.labelValuesErrors.Inc()
-			err = fmt.Errorf("cannot get label values from vmstorage %s: %w", sn.connPool.Addr(), err)
-		}
-		return &nodeResult{
-			labelValues: labelValues,
-			err:         err,
+			return []*nodeResult{{
+				err: err,
+			}}
 		}
+
+		return execSearchQuery(qt, sq, func(qt *querytracer.Tracer, requestData []byte, _ storage.TenantToken) any {
+			sn.labelValuesRequests.Inc()
+			labelValues, err := sn.getLabelValues(qt, labelName, requestData, maxLabelValues, deadline)
+			if err != nil {
+				sn.labelValuesErrors.Inc()
+				err = fmt.Errorf("cannot get label values from vmstorage %s: %w", sn.connPool.Addr(), err)
+			}
+			return &nodeResult{
+				labelValues: labelValues,
+				err:         err,
+			}
+		})
 	})
 
 	// Collect results
 	var labelValues []string
 	isPartial, err := snr.collectResults(partialLabelValuesResults, func(result any) error {
-		nr := result.(*nodeResult)
-		if nr.err != nil {
-			return nr.err
+		for _, cr := range result.([]any) {
+			nr := cr.(*nodeResult)
+			if nr.err != nil {
+				return nr.err
+			}
+			labelValues = append(labelValues, nr.labelValues...)
 		}
-		labelValues = append(labelValues, nr.labelValues...)
 		return nil
 	})
 	qt.Printf("get %d non-duplicated label values", len(labelValues))
 	if err != nil {
 		return nil, isPartial, fmt.Errorf("cannot fetch label values from vmstorage nodes: %w", err)
 	}
+	labelValues = prepareLabelValues(qt, labelValues, maxLabelValues)
+	return labelValues, isPartial, nil
+}
 
+func prepareLabelValues(qt *querytracer.Tracer, labelValues []string, maxLabelValues int) []string {
+	qt.Printf("get %d non-duplicated label values", len(labelValues))
 	// Deduplicate label values
 	labelValues = deduplicateStrings(labelValues)
 	qt.Printf("get %d unique label values after de-duplication", len(labelValues))
@@ -1024,7 +1105,7 @@ func LabelValues(qt *querytracer.Tracer, denyPartialResponse bool, labelName str
 	}
 	sort.Strings(labelValues)
 	qt.Printf("sort %d label values", len(labelValues))
-	return labelValues, isPartial, nil
+	return labelValues
 }
 
 // Tenants returns tenants until the given deadline.
@@ -1110,7 +1191,8 @@ func GraphiteTagValues(qt *querytracer.Tracer, accountID, projectID uint32, deny
 //
 // It can be used for implementing https://graphite-api.readthedocs.io/en/latest/api.html#metrics-find
 func TagValueSuffixes(qt *querytracer.Tracer, accountID, projectID uint32, denyPartialResponse bool, tr storage.TimeRange, tagKey, tagValuePrefix string,
-	delimiter byte, maxSuffixes int, deadline searchutils.Deadline) ([]string, bool, error) {
+	delimiter byte, maxSuffixes int, deadline searchutils.Deadline,
+) ([]string, bool, error) {
 	qt = qt.NewChild("get tag value suffixes for tagKey=%s, tagValuePrefix=%s, maxSuffixes=%d, timeRange=%s", tagKey, tagValuePrefix, maxSuffixes, &tr)
 	defer qt.Done()
 	if deadline.Exceeded() {
@@ -1180,7 +1262,6 @@ func TSDBStatus(qt *querytracer.Tracer, denyPartialResponse bool, sq *storage.Se
 	if deadline.Exceeded() {
 		return nil, false, fmt.Errorf("timeout exceeded before starting the query processing: %s", deadline.String())
 	}
-	requestData := sq.Marshal(nil)
 	// Send the query to all the storage nodes in parallel.
 	type nodeResult struct {
 		status *storage.TSDBStatus
@@ -1188,26 +1269,37 @@ func TSDBStatus(qt *querytracer.Tracer, denyPartialResponse bool, sq *storage.Se
 	}
 	sns := getStorageNodes()
 	snr := startStorageNodesRequest(qt, sns, denyPartialResponse, func(qt *querytracer.Tracer, _ uint, sn *storageNode) any {
-		sn.tsdbStatusRequests.Inc()
-		status, err := sn.getTSDBStatus(qt, requestData, focusLabel, topN, deadline)
+		err := populateSqTenantTokensIfNeeded(sq)
 		if err != nil {
-			sn.tsdbStatusErrors.Inc()
-			err = fmt.Errorf("cannot obtain tsdb status from vmstorage %s: %w", sn.connPool.Addr(), err)
-		}
-		return &nodeResult{
-			status: status,
-			err:    err,
+			return []*nodeResult{{
+				err: err,
+			}}
 		}
+
+		return execSearchQuery(qt, sq, func(qt *querytracer.Tracer, requestData []byte, _ storage.TenantToken) any {
+			sn.tsdbStatusRequests.Inc()
+			status, err := sn.getTSDBStatus(qt, requestData, focusLabel, topN, deadline)
+			if err != nil {
+				sn.tsdbStatusErrors.Inc()
+				err = fmt.Errorf("cannot obtain tsdb status from vmstorage %s: %w", sn.connPool.Addr(), err)
+			}
+			return &nodeResult{
+				status: status,
+				err:    err,
+			}
+		})
 	})
 
 	// Collect results.
 	var statuses []*storage.TSDBStatus
 	isPartial, err := snr.collectResults(partialTSDBStatusResults, func(result any) error {
-		nr := result.(*nodeResult)
-		if nr.err != nil {
-			return nr.err
+		for _, cr := range result.([]any) {
+			nr := cr.(*nodeResult)
+			if nr.err != nil {
+				return nr.err
+			}
+			statuses = append(statuses, nr.status)
 		}
-		statuses = append(statuses, nr.status)
 		return nil
 	})
 	if err != nil {
@@ -1559,7 +1651,8 @@ var metricNamePool = &sync.Pool{
 // It is the responsibility of f to call b.UnmarshalData before reading timestamps and values from the block.
 // It is the responsibility of f to filter blocks according to the given tr.
 func ExportBlocks(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline searchutils.Deadline,
-	f func(mn *storage.MetricName, b *storage.Block, tr storage.TimeRange, workerID uint) error) error {
+	f func(mn *storage.MetricName, b *storage.Block, tr storage.TimeRange, workerID uint) error,
+) error {
 	qt = qt.NewChild("export blocks: %s", sq)
 	defer qt.Done()
 	if deadline.Exceeded() {
@@ -1577,6 +1670,7 @@ func ExportBlocks(qt *querytracer.Tracer, sq *storage.SearchQuery, deadline sear
 		if err := mn.Unmarshal(mb.MetricName); err != nil {
 			return fmt.Errorf("cannot unmarshal metricName: %w", err)
 		}
+		metricNameTenantToTags(mn)
 		if err := f(mn, &mb.Block, tr, workerID); err != nil {
 			return err
 		}
@@ -1603,7 +1697,6 @@ func SearchMetricNames(qt *querytracer.Tracer, denyPartialResponse bool, sq *sto
 	if deadline.Exceeded() {
 		return nil, false, fmt.Errorf("timeout exceeded before starting to search metric names: %s", deadline.String())
 	}
-	requestData := sq.Marshal(nil)
 
 	// Send the query to all the storage nodes in parallel.
 	type nodeResult struct {
@@ -1612,27 +1705,47 @@ func SearchMetricNames(qt *querytracer.Tracer, denyPartialResponse bool, sq *sto
 	}
 	sns := getStorageNodes()
 	snr := startStorageNodesRequest(qt, sns, denyPartialResponse, func(qt *querytracer.Tracer, _ uint, sn *storageNode) any {
-		sn.searchMetricNamesRequests.Inc()
-		metricNames, err := sn.processSearchMetricNames(qt, requestData, deadline)
+		err := populateSqTenantTokensIfNeeded(sq)
 		if err != nil {
-			sn.searchMetricNamesErrors.Inc()
-			err = fmt.Errorf("cannot search metric names on vmstorage %s: %w", sn.connPool.Addr(), err)
-		}
-		return &nodeResult{
-			metricNames: metricNames,
-			err:         err,
+			return []*nodeResult{{
+				err: err,
+			}}
 		}
+		return execSearchQuery(qt, sq, func(qt *querytracer.Tracer, requestData []byte, t storage.TenantToken) any {
+			sn.searchMetricNamesRequests.Inc()
+			metricNames, err := sn.processSearchMetricNames(qt, requestData, deadline)
+			if sq.IsMultiTenant {
+				// TODO: (@f41gh7) this function could produce duplicate labels
+				// if original metricName already have tenant labels
+				// fix it later
+				suffix := marshalAsTags(t.AccountID, t.ProjectID)
+				suffixStr := string(suffix)
+				for i := range metricNames {
+					metricNames[i] = metricNames[i] + suffixStr
+				}
+			}
+			if err != nil {
+				sn.searchMetricNamesErrors.Inc()
+				err = fmt.Errorf("cannot search metric names on vmstorage %s: %w", sn.connPool.Addr(), err)
+			}
+			return &nodeResult{
+				metricNames: metricNames,
+				err:         err,
+			}
+		})
 	})
 
 	// Collect results.
 	metricNamesMap := make(map[string]struct{})
 	isPartial, err := snr.collectResults(partialSearchMetricNamesResults, func(result any) error {
-		nr := result.(*nodeResult)
-		if nr.err != nil {
-			return nr.err
-		}
-		for _, metricName := range nr.metricNames {
-			metricNamesMap[metricName] = struct{}{}
+		for _, cr := range result.([]any) {
+			nr := cr.(*nodeResult)
+			if nr.err != nil {
+				return nr.err
+			}
+			for _, metricName := range nr.metricNames {
+				metricNamesMap[metricName] = struct{}{}
+			}
 		}
 		return nil
 	})
@@ -1644,11 +1757,22 @@ func SearchMetricNames(qt *querytracer.Tracer, denyPartialResponse bool, sq *sto
 	for metricName := range metricNamesMap {
 		metricNames = append(metricNames, metricName)
 	}
-	sort.Strings(metricNames)
 	qt.Printf("sort %d metric names", len(metricNames))
 	return metricNames, isPartial, nil
 }
 
+func marshalAsTags(accountID, projectID uint32) []byte {
+	buf := make([]byte, 0, 64)
+	var tag storage.Tag
+	tag.Key = []byte("vm_account_id")
+	tag.Value = strconv.AppendUint(tag.Value, uint64(accountID), 10)
+	buf = tag.Marshal(buf)
+	tag.Key = []byte("vm_project_id")
+	tag.Value = strconv.AppendUint(tag.Value[:0], uint64(projectID), 10)
+	buf = tag.Marshal(buf)
+	return buf
+}
+
 // limitExceededErr error generated by vmselect
 // on checking complexity limits during processing responses
 // from storage nodes.
@@ -1722,21 +1846,22 @@ func ProcessSearchQuery(qt *querytracer.Tracer, denyPartialResponse bool, sq *st
 			addrs:      addrssPool[m[metricName]].addrs,
 		}
 	}
+	rss.shouldConvertTenantToLabels = sq.IsMultiTenant
 	rss.packedTimeseries = pts
 	return &rss, isPartial, nil
 }
 
 // ProcessBlocks calls processBlock per each block matching the given sq.
 func ProcessBlocks(qt *querytracer.Tracer, denyPartialResponse bool, sq *storage.SearchQuery,
-	processBlock func(mb *storage.MetricBlock, workerID uint) error, deadline searchutils.Deadline) (bool, error) {
+	processBlock func(mb *storage.MetricBlock, workerID uint) error, deadline searchutils.Deadline,
+) (bool, error) {
 	sns := getStorageNodes()
 	return processBlocks(qt, sns, denyPartialResponse, sq, processBlock, deadline)
 }
 
 func processBlocks(qt *querytracer.Tracer, sns []*storageNode, denyPartialResponse bool, sq *storage.SearchQuery,
-	processBlock func(mb *storage.MetricBlock, workerID uint) error, deadline searchutils.Deadline) (bool, error) {
-	requestData := sq.Marshal(nil)
-
+	processBlock func(mb *storage.MetricBlock, workerID uint) error, deadline searchutils.Deadline,
+) (bool, error) {
 	// Make sure that processBlock is no longer called after the exit from processBlocks() function.
 	// Use per-worker WaitGroup instead of a shared WaitGroup in order to avoid inter-CPU contention,
 	// which may significantly slow down the rate of processBlock calls on multi-CPU systems.
@@ -1773,12 +1898,31 @@ func processBlocks(qt *querytracer.Tracer, sns []*storageNode, denyPartialRespon
 
 	// Send the query to all the storage nodes in parallel.
 	snr := startStorageNodesRequest(qt, sns, denyPartialResponse, func(qt *querytracer.Tracer, workerID uint, sn *storageNode) any {
-		sn.searchRequests.Inc()
-		err := sn.processSearchQuery(qt, requestData, f, workerID, deadline)
+		var err error
+		err = populateSqTenantTokensIfNeeded(sq)
 		if err != nil {
-			sn.searchErrors.Inc()
-			err = fmt.Errorf("cannot perform search on vmstorage %s: %w", sn.connPool.Addr(), err)
+			return &err
 		}
+
+		res := execSearchQuery(qt, sq, func(qt *querytracer.Tracer, rd []byte, _ storage.TenantToken) any {
+			sn.searchRequests.Inc()
+			err = sn.processSearchQuery(qt, rd, f, workerID, deadline)
+			if err != nil {
+				sn.searchErrors.Inc()
+				err = fmt.Errorf("cannot perform search on vmstorage %s: %w", sn.connPool.Addr(), err)
+				return &err
+			}
+
+			return &err
+		})
+
+		for _, e := range res {
+			e := e.(*error)
+			if *e != nil {
+				return e
+			}
+		}
+
 		return &err
 	})
 
@@ -1803,6 +1947,21 @@ func processBlocks(qt *querytracer.Tracer, sns []*storageNode, denyPartialRespon
 	return isPartial, nil
 }
 
+func populateSqTenantTokensIfNeeded(sq *storage.SearchQuery) error {
+	if !sq.IsMultiTenant {
+		return nil
+	}
+
+	if len(sq.TagFilterss) == 0 {
+		return nil
+	}
+
+	tts, tfss := ApplyTenantFiltersToTagFilters(sq.TenantTokens, sq.TagFilterss)
+	sq.TenantTokens = tts
+	sq.TagFilterss = tfss
+	return nil
+}
+
 type storageNodesRequest struct {
 	denyPartialResponse bool
 	resultsCh           chan rpcResult
@@ -1817,7 +1976,8 @@ type rpcResult struct {
 }
 
 func startStorageNodesRequest(qt *querytracer.Tracer, sns []*storageNode, denyPartialResponse bool,
-	f func(qt *querytracer.Tracer, workerID uint, sn *storageNode) any) *storageNodesRequest {
+	f func(qt *querytracer.Tracer, workerID uint, sn *storageNode) any,
+) *storageNodesRequest {
 	resultsCh := make(chan rpcResult, len(sns))
 	qts := make(map[*querytracer.Tracer]struct{}, len(sns))
 	for idx, sn := range sns {
@@ -2184,7 +2344,8 @@ func (sn *storageNode) getTenants(qt *querytracer.Tracer, tr storage.TimeRange,
 }
 
 func (sn *storageNode) getTagValueSuffixes(qt *querytracer.Tracer, accountID, projectID uint32, tr storage.TimeRange, tagKey, tagValuePrefix string,
-	delimiter byte, maxSuffixes int, deadline searchutils.Deadline) ([]string, error) {
+	delimiter byte, maxSuffixes int, deadline searchutils.Deadline,
+) ([]string, error) {
 	var suffixes []string
 	f := func(bc *handshake.BufferedConn) error {
 		ss, err := sn.getTagValueSuffixesOnConn(bc, accountID, projectID, tr, tagKey, tagValuePrefix, delimiter, maxSuffixes)
@@ -2249,7 +2410,8 @@ func (sn *storageNode) processSearchMetricNames(qt *querytracer.Tracer, requestD
 }
 
 func (sn *storageNode) processSearchQuery(qt *querytracer.Tracer, requestData []byte, processBlock func(mb *storage.MetricBlock, workerID uint) error,
-	workerID uint, deadline searchutils.Deadline) error {
+	workerID uint, deadline searchutils.Deadline,
+) error {
 	f := func(bc *handshake.BufferedConn) error {
 		return sn.processSearchQueryOnConn(bc, requestData, processBlock, workerID)
 	}
@@ -2490,8 +2652,10 @@ func (sn *storageNode) getLabelNamesOnConn(bc *handshake.BufferedConn, requestDa
 	}
 }
 
-const maxLabelValueSize = 16 * 1024 * 1024
-const maxTenantValueSize = 16 * 1024 * 1024 // TODO: calc 'uint32:uint32'
+const (
+	maxLabelValueSize  = 16 * 1024 * 1024
+	maxTenantValueSize = 16 * 1024 * 1024 // TODO: calc 'uint32:uint32'
+)
 
 func (sn *storageNode) getLabelValuesOnConn(bc *handshake.BufferedConn, labelName string, requestData []byte, maxLabelValues int) ([]string, error) {
 	// Send the request to sn.
@@ -2575,7 +2739,8 @@ func (sn *storageNode) getTenantsOnConn(bc *handshake.BufferedConn, tr storage.T
 }
 
 func (sn *storageNode) getTagValueSuffixesOnConn(bc *handshake.BufferedConn, accountID, projectID uint32,
-	tr storage.TimeRange, tagKey, tagValuePrefix string, delimiter byte, maxSuffixes int) ([]string, error) {
+	tr storage.TimeRange, tagKey, tagValuePrefix string, delimiter byte, maxSuffixes int,
+) ([]string, error) {
 	// Send the request to sn.
 	if err := sendAccountIDProjectID(bc, accountID, projectID); err != nil {
 		return nil, err
@@ -2789,7 +2954,8 @@ func (sn *storageNode) processSearchMetricNamesOnConn(bc *handshake.BufferedConn
 const maxMetricNameSize = 64 * 1024
 
 func (sn *storageNode) processSearchQueryOnConn(bc *handshake.BufferedConn, requestData []byte,
-	processBlock func(mb *storage.MetricBlock, workerID uint) error, workerID uint) error {
+	processBlock func(mb *storage.MetricBlock, workerID uint) error, workerID uint,
+) error {
 	// Send the request to sn.
 	if err := writeBytes(bc, requestData); err != nil {
 		return fmt.Errorf("cannot write requestData: %w", err)
@@ -3112,3 +3278,41 @@ func (pnc *perNodeCounter) GetTotal() uint64 {
 //
 // See https://github.com/golang/go/blob/704401ffa06c60e059c9e6e4048045b4ff42530a/src/runtime/malloc.go#L11
 const maxFastAllocBlockSize = 32 * 1024
+
+// execSearchQuery calls cb for with marshaled requestData for each tenant in sq.
+func execSearchQuery(qt *querytracer.Tracer, sq *storage.SearchQuery, cb func(qt *querytracer.Tracer, requestData []byte, t storage.TenantToken) any) []any {
+	var requestData []byte
+	var results []any
+
+	for i := range sq.TenantTokens {
+		requestData = sq.TenantTokens[i].Marshal(requestData)
+		requestData = sq.MarshaWithoutTenant(requestData)
+		qtL := qt
+		if sq.IsMultiTenant && qt.Enabled() {
+			qtL = qt.NewChild("query for tenant: %s", sq.TenantTokens[i].String())
+		}
+		r := cb(qtL, requestData, sq.TenantTokens[i])
+		if sq.IsMultiTenant {
+			qtL.Done()
+		}
+		results = append(results, r)
+		requestData = requestData[:0]
+	}
+
+	return results
+}
+
+// TenantToTags moves AccountID:ProjectID to corresponding tenant tags
+// Erases values from AccountID:ProjectID
+// TODO: @f41gh7 this function could produce duplicates
+// if original metric name have tenant labels
+func metricNameTenantToTags(mn *storage.MetricName) {
+
+	buf := make([]byte, 0, 8)
+	buf = strconv.AppendUint(buf, uint64(mn.AccountID), 10)
+	mn.AddTagBytes([]byte(`vm_account_id`), buf)
+	buf = strconv.AppendUint(buf[:0], uint64(mn.ProjectID), 10)
+	mn.AddTagBytes([]byte(`vm_project_id`), buf)
+	mn.AccountID = 0
+	mn.ProjectID = 0
+}

app/vmselect/netstorage/tenant_cache.go

@@ -0,0 +1,189 @@
+package netstorage
+
+import (
+	"flag"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/VictoriaMetrics/metrics"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/searchutils"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/auth"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/timeutil"
+)
+
+var (
+	tenantsCacheDuration = flag.Duration("search.tenantCacheExpireDuration", 5*time.Minute, "The expiry duration for list of tenants for multi-tenant queries.")
+)
+
+// TenantsCached returns the list of tenants available in the storage.
+func TenantsCached(qt *querytracer.Tracer, tr storage.TimeRange, deadline searchutils.Deadline) ([]storage.TenantToken, error) {
+	qt.Printf("fetching tenants on timeRange=%s", tr.String())
+
+	cached := tenantsCacheV.get(tr)
+	qt.Printf("fetched %d tenants from cache", len(cached))
+	if len(cached) > 0 {
+		return cached, nil
+	}
+
+	tenants, err := Tenants(qt, tr, deadline)
+	if err != nil {
+		return nil, fmt.Errorf("cannot obtain tenants: %w", err)
+	}
+
+	qt.Printf("fetched %d tenants from storage", len(tenants))
+
+	tt := make([]storage.TenantToken, len(tenants))
+	for i, t := range tenants {
+		accountID, projectID, err := auth.ParseToken(t)
+		if err != nil {
+			return nil, fmt.Errorf("cannot parse tenant token %q: %w", t, err)
+		}
+		tt[i].AccountID = accountID
+		tt[i].ProjectID = projectID
+	}
+
+	tenantsCacheV.put(tr, tt)
+	qt.Printf("put %d tenants into cache", len(tenants))
+
+	return tt, nil
+}
+
+var tenantsCacheV = func() *tenantsCache {
+	tc := newTenantsCache(*tenantsCacheDuration)
+	return tc
+}()
+
+type tenantsCacheItem struct {
+	tenants []storage.TenantToken
+	tr      storage.TimeRange
+	expires time.Time
+}
+
+type tenantsCache struct {
+	// items is used for intersection matches lookup
+	items []*tenantsCacheItem
+
+	itemExpiration time.Duration
+
+	requests atomic.Uint64
+	misses   atomic.Uint64
+
+	mu sync.Mutex
+}
+
+func newTenantsCache(expiration time.Duration) *tenantsCache {
+	tc := &tenantsCache{
+		items:          make([]*tenantsCacheItem, 0),
+		itemExpiration: expiration,
+	}
+
+	metrics.GetOrCreateGauge(`vm_cache_requests_total{type="multitenancy/tenants"}`, func() float64 {
+		return float64(tc.Requests())
+	})
+	metrics.GetOrCreateGauge(`vm_cache_misses_total{type="multitenancy/tenants"}`, func() float64 {
+		return float64(tc.Misses())
+	})
+	metrics.GetOrCreateGauge(`vm_cache_entries{type="multitenancy/tenants"}`, func() float64 {
+		return float64(tc.Len())
+	})
+
+	return tc
+}
+
+func (tc *tenantsCache) cleanupLocked() {
+	expires := time.Now().Add(tc.itemExpiration)
+	for i := len(tc.items) - 1; i >= 0; i-- {
+		if tc.items[i].expires.Before(expires) {
+			tc.items = append(tc.items[:i], tc.items[i+1:]...)
+		}
+	}
+}
+
+func (tc *tenantsCache) put(tr storage.TimeRange, tenants []storage.TenantToken) {
+	tc.mu.Lock()
+	defer tc.mu.Unlock()
+	alignTrToDay(&tr)
+
+	exp := time.Now().Add(timeutil.AddJitterToDuration(tc.itemExpiration))
+
+	ci := &tenantsCacheItem{
+		tenants: tenants,
+		tr:      tr,
+		expires: exp,
+	}
+
+	tc.items = append(tc.items, ci)
+}
+func (tc *tenantsCache) Requests() uint64 {
+	return tc.requests.Load()
+}
+
+func (tc *tenantsCache) Misses() uint64 {
+	return tc.misses.Load()
+}
+
+func (tc *tenantsCache) Len() uint64 {
+	tc.mu.Lock()
+	n := len(tc.items)
+	tc.mu.Unlock()
+	return uint64(n)
+}
+
+func (tc *tenantsCache) get(tr storage.TimeRange) []storage.TenantToken {
+	tc.requests.Add(1)
+
+	alignTrToDay(&tr)
+	return tc.getInternal(tr)
+}
+
+func (tc *tenantsCache) getInternal(tr storage.TimeRange) []storage.TenantToken {
+	tc.mu.Lock()
+	defer tc.mu.Unlock()
+	if len(tc.items) == 0 {
+		return nil
+	}
+
+	result := make(map[storage.TenantToken]struct{})
+	cleanupNeeded := false
+	for idx := range tc.items {
+		ci := tc.items[idx]
+		if ci.expires.Before(time.Now()) {
+			cleanupNeeded = true
+		}
+
+		if hasIntersection(tr, ci.tr) {
+			for _, t := range ci.tenants {
+				result[t] = struct{}{}
+			}
+		}
+	}
+
+	if cleanupNeeded {
+		tc.cleanupLocked()
+	}
+
+	tenants := make([]storage.TenantToken, 0, len(result))
+	for t := range result {
+		tenants = append(tenants, t)
+	}
+
+	return tenants
+}
+
+// alignTrToDay aligns the given time range to the day boundaries
+// tr.minTimestamp will be set to the start of the day
+// tr.maxTimestamp will be set to the end of the day
+func alignTrToDay(tr *storage.TimeRange) {
+	tr.MinTimestamp = timeutil.StartOfDay(tr.MinTimestamp)
+	tr.MaxTimestamp = timeutil.EndOfDay(tr.MaxTimestamp)
+}
+
+// hasIntersection checks if there is any intersection of the given time ranges
+func hasIntersection(a, b storage.TimeRange) bool {
+	return a.MinTimestamp <= b.MaxTimestamp && a.MaxTimestamp >= b.MinTimestamp
+}

app/vmselect/netstorage/tenant_cache_test.go

@@ -0,0 +1,91 @@
+package netstorage
+
+import (
+	"reflect"
+	"sort"
+	"testing"
+	"time"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
+)
+
+func TestFetchingTenants(t *testing.T) {
+	tc := newTenantsCache(5 * time.Second)
+
+	dayMs := (time.Hour * 24 * 1000).Milliseconds()
+
+	tc.put(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 0}, []storage.TenantToken{
+		{AccountID: 1, ProjectID: 1},
+		{AccountID: 1, ProjectID: 0},
+	})
+	tc.put(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: dayMs - 1}, []storage.TenantToken{
+		{AccountID: 1, ProjectID: 1},
+		{AccountID: 1, ProjectID: 0},
+	})
+	tc.put(storage.TimeRange{MinTimestamp: dayMs, MaxTimestamp: 2*dayMs - 1}, []storage.TenantToken{
+		{AccountID: 2, ProjectID: 1},
+		{AccountID: 2, ProjectID: 0},
+	})
+	tc.put(storage.TimeRange{MinTimestamp: 2 * dayMs, MaxTimestamp: 3*dayMs - 1}, []storage.TenantToken{
+		{AccountID: 3, ProjectID: 1},
+		{AccountID: 3, ProjectID: 0},
+	})
+
+	f := func(tr storage.TimeRange, expectedTenants []storage.TenantToken) {
+		t.Helper()
+		tenants := tc.get(tr)
+
+		if len(tenants) == 0 && len(tenants) == len(expectedTenants) {
+			return
+		}
+
+		sortTenants := func(t []storage.TenantToken) func(i, j int) bool {
+			return func(i, j int) bool {
+				if t[i].AccountID == t[j].AccountID {
+					return t[i].ProjectID < t[j].ProjectID
+				}
+				return t[i].AccountID < t[j].AccountID
+			}
+		}
+		sort.Slice(tenants, sortTenants(tenants))
+		sort.Slice(expectedTenants, sortTenants(expectedTenants))
+
+		if !reflect.DeepEqual(tenants, expectedTenants) {
+			t.Fatalf("unexpected tenants; got %v; want %v", tenants, expectedTenants)
+		}
+	}
+
+	// Basic time range coverage
+	f(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 0}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 100}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: dayMs, MaxTimestamp: dayMs}, []storage.TenantToken{{AccountID: 2, ProjectID: 1}, {AccountID: 2, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: 2 * dayMs, MaxTimestamp: 2 * dayMs}, []storage.TenantToken{{AccountID: 3, ProjectID: 1}, {AccountID: 3, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: 3 * dayMs, MaxTimestamp: 3*dayMs + 1}, []storage.TenantToken{})
+
+	// Time range inside existing range
+	f(storage.TimeRange{MinTimestamp: dayMs / 2, MaxTimestamp: dayMs/2 + 100}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: dayMs + dayMs/2, MaxTimestamp: dayMs + dayMs/2 + 100}, []storage.TenantToken{{AccountID: 2, ProjectID: 1}, {AccountID: 2, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: dayMs / 2}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: dayMs / 2, MaxTimestamp: dayMs - 1}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}})
+
+	// Overlapping time ranges
+	f(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 2*dayMs - 1}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}, {AccountID: 2, ProjectID: 1}, {AccountID: 2, ProjectID: 0}})
+	f(storage.TimeRange{MinTimestamp: dayMs / 2, MaxTimestamp: dayMs + dayMs/2}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}, {AccountID: 2, ProjectID: 1}, {AccountID: 2, ProjectID: 0}})
+}
+
+func TestHasIntersection(t *testing.T) {
+	f := func(inner, outer storage.TimeRange, expected bool) {
+		t.Helper()
+		if hasIntersection(inner, outer) != expected {
+			t.Fatalf("unexpected result for inner=%+v, outer=%+v", inner, outer)
+		}
+	}
+
+	f(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 150}, storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 0}, true)
+	f(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 150}, storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 100}, true)
+	f(storage.TimeRange{MinTimestamp: 50, MaxTimestamp: 150}, storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 100}, true)
+	f(storage.TimeRange{MinTimestamp: 50, MaxTimestamp: 150}, storage.TimeRange{MinTimestamp: 10, MaxTimestamp: 80}, true)
+
+	f(storage.TimeRange{MinTimestamp: 0, MaxTimestamp: 50}, storage.TimeRange{MinTimestamp: 60, MaxTimestamp: 100}, false)
+	f(storage.TimeRange{MinTimestamp: 100, MaxTimestamp: 150}, storage.TimeRange{MinTimestamp: 60, MaxTimestamp: 80}, false)
+}

app/vmselect/netstorage/tenant_filters.go

@@ -0,0 +1,129 @@
+package netstorage
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/searchutils"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/prompbmarshal"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promrelabel"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
+)
+
+// GetTenantTokensFromFilters returns the list of tenant tokens and the list of filters without tenant filters.
+func GetTenantTokensFromFilters(qt *querytracer.Tracer, tr storage.TimeRange, tfs [][]storage.TagFilter, deadline searchutils.Deadline) ([]storage.TenantToken, [][]storage.TagFilter, error) {
+	tenants, err := TenantsCached(qt, tr, deadline)
+	if err != nil {
+		return nil, nil, fmt.Errorf("cannot obtain tenants: %w", err)
+	}
+
+	tenantFilters, otherFilters := splitFiltersByType(tfs)
+
+	tts, err := applyFiltersToTenants(tenants, tenantFilters)
+	if err != nil {
+		return nil, nil, fmt.Errorf("cannot apply filters to tenants: %w", err)
+	}
+
+	return tts, otherFilters, nil
+}
+
+func splitFiltersByType(tfs [][]storage.TagFilter) ([][]storage.TagFilter, [][]storage.TagFilter) {
+	if len(tfs) == 0 {
+		return nil, tfs
+	}
+
+	tenantFilters := make([][]storage.TagFilter, 0, len(tfs))
+	otherFilters := make([][]storage.TagFilter, 0, len(tfs))
+	for _, f := range tfs {
+		ffs := make([]storage.TagFilter, 0, len(f))
+		offs := make([]storage.TagFilter, 0, len(f))
+		for _, tf := range f {
+			if !isTenancyLabel(string(tf.Key)) {
+				offs = append(offs, tf)
+				continue
+			}
+			ffs = append(ffs, tf)
+		}
+
+		if len(ffs) > 0 {
+			tenantFilters = append(tenantFilters, ffs)
+		}
+		if len(offs) > 0 {
+			otherFilters = append(otherFilters, offs)
+		}
+	}
+	return tenantFilters, otherFilters
+}
+
+// ApplyTenantFiltersToTagFilters applies the given tenant filters to the given tag filters.
+func ApplyTenantFiltersToTagFilters(tts []storage.TenantToken, tfs [][]storage.TagFilter) ([]storage.TenantToken, [][]storage.TagFilter) {
+	tenantFilters, otherFilters := splitFiltersByType(tfs)
+	if len(tenantFilters) == 0 {
+		return tts, otherFilters
+	}
+
+	tts, err := applyFiltersToTenants(tts, tenantFilters)
+	if err != nil {
+		return nil, nil
+	}
+	return tts, otherFilters
+}
+
+func tagFiltersToString(tfs []storage.TagFilter) string {
+	a := make([]string, len(tfs))
+	for i, tf := range tfs {
+		a[i] = tf.String()
+	}
+	return "{" + strings.Join(a, ",") + "}"
+}
+
+// applyFiltersToTenants applies the given filters to the given tenants.
+// It returns the filtered tenants.
+func applyFiltersToTenants(tenants []storage.TenantToken, filters [][]storage.TagFilter) ([]storage.TenantToken, error) {
+	// fast path - return all tenants if no filters are given
+	if len(filters) == 0 {
+		return tenants, nil
+	}
+
+	resultingTokens := make([]storage.TenantToken, 0, len(tenants))
+	lbs := make([][]prompbmarshal.Label, 0, len(filters))
+	lbsAux := make([]prompbmarshal.Label, 0, len(filters))
+	for _, token := range tenants {
+		lbsAuxLen := len(lbsAux)
+		lbsAux = append(lbsAux, prompbmarshal.Label{
+			Name:  "vm_account_id",
+			Value: fmt.Sprintf("%d", token.AccountID),
+		}, prompbmarshal.Label{
+			Name:  "vm_project_id",
+			Value: fmt.Sprintf("%d", token.ProjectID),
+		})
+
+		lbs = append(lbs, lbsAux[lbsAuxLen:])
+	}
+
+	promIfs := make([]promrelabel.IfExpression, len(filters))
+	for i, tags := range filters {
+		filter := tagFiltersToString(tags)
+		err := promIfs[i].Parse(filter)
+		if err != nil {
+			return nil, fmt.Errorf("cannot parse if expression from filters %v: %s", filter, err)
+		}
+	}
+
+	for i, lb := range lbs {
+		for _, promIf := range promIfs {
+			if promIf.Match(lb) {
+				resultingTokens = append(resultingTokens, tenants[i])
+				break
+			}
+		}
+	}
+
+	return resultingTokens, nil
+}
+
+// isTenancyLabel returns true if the given label name is used for tenancy.
+func isTenancyLabel(name string) bool {
+	return name == "vm_account_id" || name == "vm_project_id"
+}

app/vmselect/netstorage/tenant_filters_test.go

@@ -0,0 +1,52 @@
+package netstorage
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
+)
+
+func TestApplyFiltersToTenants(t *testing.T) {
+	f := func(filters [][]storage.TagFilter, tenants []storage.TenantToken, expectedTenants []storage.TenantToken) {
+		tenantsResult, err := applyFiltersToTenants(tenants, filters)
+		if err != nil {
+			t.Fatalf("unexpected error: %s", err)
+		}
+
+		if !reflect.DeepEqual(tenantsResult, expectedTenants) {
+			t.Fatalf("unexpected tenants result; got %v; want %v", tenantsResult, expectedTenants)
+		}
+	}
+
+	f(nil, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}})
+
+	f([][]storage.TagFilter{{{Key: []byte("vm_account_id"), Value: []byte("1"), IsNegative: false, IsRegexp: false}}}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}})
+	f([][]storage.TagFilter{{{Key: []byte("vm_account_id"), Value: []byte("1"), IsNegative: false, IsRegexp: false}, {Key: []byte("vm_project_id"), Value: []byte("0"), IsNegative: false, IsRegexp: false}}}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}}, []storage.TenantToken{{AccountID: 1, ProjectID: 0}})
+
+	f([][]storage.TagFilter{{{Key: []byte("vm_account_id"), Value: []byte("1[0-9]+"), IsNegative: false, IsRegexp: true}}}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 12323, ProjectID: 0}, {AccountID: 12323, ProjectID: 3}, {AccountID: 345, ProjectID: 0}}, []storage.TenantToken{{AccountID: 12323, ProjectID: 0}, {AccountID: 12323, ProjectID: 3}})
+
+	f([][]storage.TagFilter{{{Key: []byte("vm_account_id"), Value: []byte("1"), IsNegative: false, IsRegexp: false}, {Key: []byte("vm_project_id"), Value: []byte("0"), IsNegative: true, IsRegexp: false}}}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}, {AccountID: 1, ProjectID: 0}}, []storage.TenantToken{{AccountID: 1, ProjectID: 1}})
+}
+
+func TestIsTenancyLabel(t *testing.T) {
+	f := func(label string, expected bool) {
+		t.Helper()
+		isTenancyLabel := isTenancyLabel(label)
+		if isTenancyLabel != expected {
+			t.Fatalf("unexpected result for label %q; got %v; want %v", label, isTenancyLabel, expected)
+		}
+	}
+
+	f("vm_account_id", true)
+	f("vm_project_id", true)
+
+	// Test that the label is case-insensitive
+	f("VM_account_id", false)
+	f("VM_project_id", false)
+
+	// non-tenancy labels
+	f("job", false)
+	f("instance", false)
+
+}

app/vmselect/prometheus/prometheus.go

@@ -13,6 +13,11 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/VictoriaMetrics/metrics"
+	"github.com/VictoriaMetrics/metricsql"
+
+	"github.com/valyala/fastjson/fastfloat"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/netstorage"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/promql"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/querystats"
@@ -28,9 +33,6 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
-	"github.com/VictoriaMetrics/metrics"
-	"github.com/VictoriaMetrics/metricsql"
-	"github.com/valyala/fastjson/fastfloat"
 )
 
 var (
@@ -124,7 +126,10 @@ func FederateHandler(startTime time.Time, at *auth.Token, w http.ResponseWriter,
 	if cp.IsDefaultTimeRange() {
 		cp.start = cp.end - lookbackDelta
 	}
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, *maxFederateSeries)
+	sq, err := getSearchQuery(nil, at, cp, *maxFederateSeries)
+	if err != nil {
+		return fmt.Errorf("cannot obtain search query: %w", err)
+	}
 	denyPartialResponse := httputils.GetDenyPartialResponse(r)
 	rss, isPartial, err := netstorage.ProcessSearchQuery(nil, denyPartialResponse, sq, cp.deadline)
 	if err != nil {
@@ -170,7 +175,10 @@ func ExportCSVHandler(startTime time.Time, at *auth.Token, w http.ResponseWriter
 	fieldNames := strings.Split(format, ",")
 	reduceMemUsage := httputils.GetBool(r, "reduce_mem_usage")
 
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, *maxExportSeries)
+	sq, err := getSearchQuery(nil, at, cp, *maxExportSeries)
+	if err != nil {
+		return fmt.Errorf("cannot obtain search query: %w", err)
+	}
 	w.Header().Set("Content-Type", "text/csv; charset=utf-8")
 	bw := bufferedwriter.Get(w)
 	defer bufferedwriter.Put(bw)
@@ -250,7 +258,10 @@ func ExportNativeHandler(startTime time.Time, at *auth.Token, w http.ResponseWri
 		return err
 	}
 
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, *maxExportSeries)
+	sq, err := getSearchQuery(nil, at, cp, *maxExportSeries)
+	if err != nil {
+		return fmt.Errorf("cannot obtain search query: %w", err)
+	}
 	w.Header().Set("Content-Type", "VictoriaMetrics/native")
 	bw := bufferedwriter.Get(w)
 	defer bufferedwriter.Put(bw)
@@ -392,7 +403,11 @@ func exportHandler(qt *querytracer.Tracer, at *auth.Token, w http.ResponseWriter
 		}
 	}
 
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, *maxExportSeries)
+	sq, err := getSearchQuery(qt, at, cp, *maxExportSeries)
+	if err != nil {
+		return fmt.Errorf("cannot obtain search query: %w", err)
+	}
+
 	w.Header().Set("Content-Type", contentType)
 
 	doneCh := make(chan error, 1)
@@ -450,7 +465,7 @@ func exportHandler(qt *querytracer.Tracer, at *auth.Token, w http.ResponseWriter
 			doneCh <- err
 		}()
 	}
-	err := <-doneCh
+	err = <-doneCh
 	if err != nil {
 		return fmt.Errorf("cannot send data to remote client: %w", err)
 	}
@@ -597,12 +612,14 @@ func LabelValuesHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.To
 		return err
 	}
 	denyPartialResponse := httputils.GetDenyPartialResponse(r)
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, *maxLabelsAPISeries)
+	sq, err := getSearchQuery(qt, at, cp, *maxLabelsAPISeries)
+	if err != nil {
+		return err
+	}
 	labelValues, isPartial, err := netstorage.LabelValues(qt, denyPartialResponse, labelName, sq, limit, cp.deadline)
 	if err != nil {
 		return fmt.Errorf("cannot obtain values for label %q: %w", labelName, err)
 	}
-
 	w.Header().Set("Content-Type", "application/json")
 	bw := bufferedwriter.Get(w)
 	defer bufferedwriter.Put(bw)
@@ -661,9 +678,12 @@ func TSDBStatusHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Tok
 		topN = n
 	}
 	denyPartialResponse := httputils.GetDenyPartialResponse(r)
-	start := int64(date*secsPerDay) * 1000
-	end := int64((date+1)*secsPerDay)*1000 - 1
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, start, end, cp.filterss, *maxTSDBStatusSeries)
+	cp.start = int64(date*secsPerDay) * 1000
+	cp.end = int64((date+1)*secsPerDay)*1000 - 1
+	sq, err := getSearchQuery(qt, at, cp, *maxTSDBStatusSeries)
+	if err != nil {
+		return err
+	}
 	status, isPartial, err := netstorage.TSDBStatus(qt, denyPartialResponse, sq, focusLabel, topN, cp.deadline)
 	if err != nil {
 		return fmt.Errorf("cannot obtain tsdb stats: %w", err)
@@ -696,7 +716,10 @@ func LabelsHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Token,
 		return err
 	}
 	denyPartialResponse := httputils.GetDenyPartialResponse(r)
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, *maxLabelsAPISeries)
+	sq, err := getSearchQuery(qt, at, cp, *maxLabelsAPISeries)
+	if err != nil {
+		return err
+	}
 	labels, isPartial, err := netstorage.LabelNames(qt, denyPartialResponse, sq, limit, cp.deadline)
 	if err != nil {
 		return fmt.Errorf("cannot obtain labels: %w", err)
@@ -712,6 +735,18 @@ func LabelsHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Token,
 	return nil
 }
 
+func getSearchQuery(qt *querytracer.Tracer, at *auth.Token, cp *commonParams, maxSeries int) (*storage.SearchQuery, error) {
+	if at != nil {
+		return storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, maxSeries), nil
+	}
+	tt, tfs, err := netstorage.GetTenantTokensFromFilters(qt, storage.TimeRange{MinTimestamp: cp.start, MaxTimestamp: cp.end}, cp.filterss, cp.deadline)
+	if err != nil {
+		return nil, fmt.Errorf("cannot obtain tenant tokens: %w", err)
+	}
+	sq := storage.NewMultiTenantSearchQuery(tt, cp.start, cp.end, tfs, maxSeries)
+	return sq, nil
+}
+
 var labelsDuration = metrics.NewSummary(`vm_request_duration_seconds{path="/api/v1/labels"}`)
 
 // SeriesCountHandler processes /api/v1/series/count request.
@@ -756,8 +791,10 @@ func SeriesHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Token,
 	if err != nil {
 		return err
 	}
-
-	sq := storage.NewSearchQuery(at.AccountID, at.ProjectID, cp.start, cp.end, cp.filterss, *maxSeriesLimit)
+	sq, err := getSearchQuery(qt, at, cp, *maxSeriesLimit)
+	if err != nil {
+		return err
+	}
 	denyPartialResponse := httputils.GetDenyPartialResponse(r)
 	metricNames, isPartial, err := netstorage.SearchMetricNames(qt, denyPartialResponse, sq, cp.deadline)
 	if err != nil {
@@ -883,7 +920,6 @@ func QueryHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Token, w
 	}
 	qs := &promql.QueryStats{}
 	ec := &promql.EvalConfig{
-		AuthToken:           at,
 		Start:               start,
 		End:                 start,
 		Step:                step,
@@ -902,6 +938,11 @@ func QueryHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Token, w
 		DenyPartialResponse: httputils.GetDenyPartialResponse(r),
 		QueryStats:          qs,
 	}
+	err = populateAuthTokens(qt, ec, at, deadline)
+	if err != nil {
+		return fmt.Errorf("cannot populate auth tokens: %w", err)
+	}
+
 	result, err := promql.Exec(qt, ec, query, true)
 	if err != nil {
 		return fmt.Errorf("error when executing query=%q for (time=%d, step=%d): %w", query, start, step, err)
@@ -993,7 +1034,6 @@ func queryRangeHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Tok
 
 	qs := &promql.QueryStats{}
 	ec := &promql.EvalConfig{
-		AuthToken:           at,
 		Start:               start,
 		End:                 end,
 		Step:                step,
@@ -1012,6 +1052,11 @@ func queryRangeHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Tok
 		DenyPartialResponse: httputils.GetDenyPartialResponse(r),
 		QueryStats:          qs,
 	}
+	err = populateAuthTokens(qt, ec, at, deadline)
+	if err != nil {
+		return fmt.Errorf("cannot populate auth tokens: %w", err)
+	}
+
 	result, err := promql.Exec(qt, ec, query, false)
 	if err != nil {
 		return err
@@ -1043,6 +1088,30 @@ func queryRangeHandler(qt *querytracer.Tracer, startTime time.Time, at *auth.Tok
 	return nil
 }
 
+func populateAuthTokens(qt *querytracer.Tracer, ec *promql.EvalConfig, at *auth.Token, deadline searchutils.Deadline) error {
+	if at != nil {
+		ec.AuthTokens = []*auth.Token{at}
+		return nil
+	}
+
+	tt, tfs, err := netstorage.GetTenantTokensFromFilters(qt, storage.TimeRange{MinTimestamp: ec.Start, MaxTimestamp: ec.End}, ec.EnforcedTagFilterss, deadline)
+	if err != nil {
+		return fmt.Errorf("cannot obtain tenant tokens for the given search query: %w", err)
+	}
+	ec.EnforcedTagFilterss = tfs
+
+	ats := make([]*auth.Token, len(tt))
+	for i, t := range tt {
+		ats[i] = &auth.Token{
+			AccountID: t.AccountID,
+			ProjectID: t.ProjectID,
+		}
+	}
+	ec.AuthTokens = ats
+	ec.IsMultiTenant = true
+	return nil
+}
+
 func removeEmptyValuesAndTimeseries(tss []netstorage.Result) []netstorage.Result {
 	dst := tss[:0]
 	for i := range tss {

app/vmselect/promql/active_queries.go

@@ -19,16 +19,16 @@ import (
 // If at is nil, then all the active queries across all the tenants are written.
 func ActiveQueriesHandler(at *auth.Token, w http.ResponseWriter, _ *http.Request) {
 	aqes := activeQueriesV.GetAll()
-	if at != nil {
-		// Filter out queries, which do not belong to at.
-		dst := aqes[:0]
-		for _, aqe := range aqes {
-			if aqe.accountID == at.AccountID && aqe.projectID == at.ProjectID {
-				dst = append(dst, aqe)
-			}
+
+	// Filter out queries, which do not belong to at.
+	// if at is nil, then all the queries are returned for multi-tenant request
+	dst := aqes[:0]
+	for _, aqe := range aqes {
+		if at == nil || (aqe.accountID == at.AccountID && aqe.projectID == at.ProjectID) {
+			dst = append(dst, aqe)
 		}
-		aqes = dst
 	}
+	aqes = dst
 	writeActiveQueries(w, aqes)
 }
 
@@ -42,8 +42,8 @@ func writeActiveQueries(w http.ResponseWriter, aqes []activeQueryEntry) {
 	fmt.Fprintf(w, `{"status":"ok","data":[`)
 	for i, aqe := range aqes {
 		d := now.Sub(aqe.startTime)
-		fmt.Fprintf(w, `{"duration":"%.3fs","id":"%016X","remote_addr":%s,"account_id":"%d","project_id":"%d","query":%s,"start":%d,"end":%d,"step":%d}`,
-			d.Seconds(), aqe.qid, aqe.quotedRemoteAddr, aqe.accountID, aqe.projectID, stringsutil.JSONString(aqe.q), aqe.start, aqe.end, aqe.step)
+		fmt.Fprintf(w, `{"duration":"%.3fs","id":"%016X","remote_addr":%s,"account_id":"%d","project_id":"%d","query":%s,"start":%d,"end":%d,"step":%d,"is_multitenant":%v}`,
+			d.Seconds(), aqe.qid, aqe.quotedRemoteAddr, aqe.accountID, aqe.projectID, stringsutil.JSONString(aqe.q), aqe.start, aqe.end, aqe.step, aqe.isMultitenant)
 		if i+1 < len(aqes) {
 			fmt.Fprintf(w, `,`)
 		}
@@ -68,6 +68,7 @@ type activeQueryEntry struct {
 	quotedRemoteAddr string
 	q                string
 	startTime        time.Time
+	isMultitenant    bool
 }
 
 func newActiveQueries() *activeQueries {
@@ -78,8 +79,12 @@ func newActiveQueries() *activeQueries {
 
 func (aq *activeQueries) Add(ec *EvalConfig, q string) uint64 {
 	var aqe activeQueryEntry
-	aqe.accountID = ec.AuthToken.AccountID
-	aqe.projectID = ec.AuthToken.ProjectID
+	if ec.IsMultiTenant {
+		aqe.isMultitenant = true
+	} else {
+		aqe.accountID = ec.AuthTokens[0].AccountID
+		aqe.projectID = ec.AuthTokens[0].ProjectID
+	}
 	aqe.start = ec.Start
 	aqe.end = ec.End
 	aqe.step = ec.Step

app/vmselect/promql/eval.go

@@ -12,6 +12,9 @@ import (
 	"time"
 	"unsafe"
 
+	"github.com/VictoriaMetrics/metrics"
+	"github.com/VictoriaMetrics/metricsql"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/netstorage"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/searchutils"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/auth"
@@ -26,8 +29,6 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/stringsutil"
-	"github.com/VictoriaMetrics/metrics"
-	"github.com/VictoriaMetrics/metricsql"
 )
 
 var (
@@ -109,10 +110,12 @@ func alignStartEnd(start, end, step int64) (int64, int64) {
 
 // EvalConfig is the configuration required for query evaluation via Exec
 type EvalConfig struct {
-	AuthToken *auth.Token
-	Start     int64
-	End       int64
-	Step      int64
+	AuthTokens    []*auth.Token
+	IsMultiTenant bool
+
+	Start int64
+	End   int64
+	Step  int64
 
 	// MaxSeries is the maximum number of time series, which can be scanned by the query.
 	// Zero means 'no limit'
@@ -160,7 +163,8 @@ type EvalConfig struct {
 // copyEvalConfig returns src copy.
 func copyEvalConfig(src *EvalConfig) *EvalConfig {
 	var ec EvalConfig
-	ec.AuthToken = src.AuthToken
+	ec.AuthTokens = src.AuthTokens
+	ec.IsMultiTenant = src.IsMultiTenant
 	ec.Start = src.Start
 	ec.End = src.End
 	ec.Step = src.Step
@@ -963,7 +967,7 @@ func evalRollupFuncWithSubquery(qt *querytracer.Tracer, ec *EvalConfig, funcName
 		return nil, nil
 	}
 	sharedTimestamps := getTimestamps(ec.Start, ec.End, ec.Step, ec.MaxPointsPerSeries)
-	preFunc, rcs, err := getRollupConfigs(funcName, rf, expr, ec.Start, ec.End, ec.Step, ec.MaxPointsPerSeries, window, ec.LookbackDelta, sharedTimestamps)
+	preFunc, rcs, err := getRollupConfigs(funcName, rf, expr, ec.Start, ec.End, ec.Step, ec.MaxPointsPerSeries, window, ec.LookbackDelta, sharedTimestamps, ec.IsMultiTenant)
 	if err != nil {
 		return nil, err
 	}
@@ -1107,13 +1111,18 @@ func evalInstantRollup(qt *querytracer.Tracer, ec *EvalConfig, funcName string,
 		}
 		return offset >= maxOffset
 	}
+
+	at := ec.AuthTokens[0]
+	if ec.IsMultiTenant {
+		at = nil
+	}
 	deleteCachedSeries := func(qt *querytracer.Tracer) {
-		rollupResultCacheV.DeleteInstantValues(qt, ec.AuthToken, expr, window, ec.Step, ec.EnforcedTagFilterss)
+		rollupResultCacheV.DeleteInstantValues(qt, at, expr, window, ec.Step, ec.EnforcedTagFilterss)
 	}
 	getCachedSeries := func(qt *querytracer.Tracer) ([]*timeseries, int64, error) {
 	again:
 		offset := int64(0)
-		tssCached := rollupResultCacheV.GetInstantValues(qt, ec.AuthToken, expr, window, ec.Step, ec.EnforcedTagFilterss)
+		tssCached := rollupResultCacheV.GetInstantValues(qt, at, expr, window, ec.Step, ec.EnforcedTagFilterss)
 		ec.QueryStats.addSeriesFetched(len(tssCached))
 		if len(tssCached) == 0 {
 			// Cache miss. Re-populate the missing data.
@@ -1139,7 +1148,7 @@ func evalInstantRollup(qt *querytracer.Tracer, ec *EvalConfig, funcName string,
 				tss, err := evalAt(qt, timestamp, window)
 				return tss, 0, err
 			}
-			rollupResultCacheV.PutInstantValues(qt, ec.AuthToken, expr, window, ec.Step, ec.EnforcedTagFilterss, tss)
+			rollupResultCacheV.PutInstantValues(qt, at, expr, window, ec.Step, ec.EnforcedTagFilterss, tss)
 			return tss, offset, nil
 		}
 		// Cache hit. Verify whether it is OK to use the cached data.
@@ -1707,7 +1716,7 @@ func evalRollupFuncNoCache(qt *querytracer.Tracer, ec *EvalConfig, funcName stri
 	}
 	// Obtain rollup configs before fetching data from db, so type errors could be caught earlier.
 	sharedTimestamps := getTimestamps(ec.Start, ec.End, ec.Step, ec.MaxPointsPerSeries)
-	preFunc, rcs, err := getRollupConfigs(funcName, rf, expr, ec.Start, ec.End, ec.Step, ec.MaxPointsPerSeries, window, ec.LookbackDelta, sharedTimestamps)
+	preFunc, rcs, err := getRollupConfigs(funcName, rf, expr, ec.Start, ec.End, ec.Step, ec.MaxPointsPerSeries, window, ec.LookbackDelta, sharedTimestamps, ec.IsMultiTenant)
 	if err != nil {
 		return nil, err
 	}
@@ -1724,7 +1733,18 @@ func evalRollupFuncNoCache(qt *querytracer.Tracer, ec *EvalConfig, funcName stri
 	} else {
 		minTimestamp -= ec.Step
 	}
-	sq := storage.NewSearchQuery(ec.AuthToken.AccountID, ec.AuthToken.ProjectID, minTimestamp, ec.End, tfss, ec.MaxSeries)
+	var sq *storage.SearchQuery
+
+	if ec.IsMultiTenant {
+		ts := make([]storage.TenantToken, len(ec.AuthTokens))
+		for i, at := range ec.AuthTokens {
+			ts[i].ProjectID = at.ProjectID
+			ts[i].AccountID = at.AccountID
+		}
+		sq = storage.NewMultiTenantSearchQuery(ts, minTimestamp, ec.End, tfss, ec.MaxSeries)
+	} else {
+		sq = storage.NewSearchQuery(ec.AuthTokens[0].AccountID, ec.AuthTokens[0].ProjectID, minTimestamp, ec.End, tfss, ec.MaxSeries)
+	}
 	rss, isPartial, err := netstorage.ProcessSearchQuery(qt, ec.DenyPartialResponse, sq, ec.Deadline)
 	if err != nil {
 		return nil, err
@@ -1955,8 +1975,6 @@ var bbPool bytesutil.ByteBufferPool
 func evalNumber(ec *EvalConfig, n float64) []*timeseries {
 	var ts timeseries
 	ts.denyReuse = true
-	ts.MetricName.AccountID = ec.AuthToken.AccountID
-	ts.MetricName.ProjectID = ec.AuthToken.ProjectID
 	timestamps := ec.getSharedTimestamps()
 	values := make([]float64, len(timestamps))
 	for i := range timestamps {

app/vmselect/promql/eval_test.go

@@ -4,9 +4,10 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/VictoriaMetrics/metricsql"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/protoparser/prometheus"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
-	"github.com/VictoriaMetrics/metricsql"
 )
 
 func TestGetCommonLabelFilters(t *testing.T) {

app/vmselect/promql/exec.go

@@ -10,14 +10,15 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/VictoriaMetrics/metrics"
+	"github.com/VictoriaMetrics/metricsql"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/netstorage"
 	"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect/querystats"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/decimal"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/querytracer"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
-	"github.com/VictoriaMetrics/metrics"
-	"github.com/VictoriaMetrics/metricsql"
 )
 
 var (
@@ -39,10 +40,14 @@ var (
 func Exec(qt *querytracer.Tracer, ec *EvalConfig, q string, isFirstPointOnly bool) ([]netstorage.Result, error) {
 	if querystats.Enabled() {
 		startTime := time.Now()
-		ac := ec.AuthToken
 		defer func() {
-			querystats.RegisterQuery(ac.AccountID, ac.ProjectID, q, ec.End-ec.Start, startTime)
 			ec.QueryStats.addExecutionTimeMsec(startTime)
+			if ec.IsMultiTenant {
+				querystats.RegisterQueryMultiTenant(q, ec.End-ec.Start, startTime)
+				return
+			}
+			at := ec.AuthTokens[0]
+			querystats.RegisterQuery(at.AccountID, at.ProjectID, q, ec.End-ec.Start, startTime)
 		}()
 	}
 

app/vmselect/promql/exec_test.go

@@ -65,10 +65,11 @@ func TestExecSuccess(t *testing.T) {
 	f := func(q string, resultExpected []netstorage.Result) {
 		t.Helper()
 		ec := &EvalConfig{
-			AuthToken: &auth.Token{
+			AuthTokens: []*auth.Token{{
 				AccountID: accountID,
 				ProjectID: projectID,
-			},
+			}},
+
 			Start:              start,
 			End:                end,
 			Step:               step,
@@ -82,7 +83,7 @@ func TestExecSuccess(t *testing.T) {
 			if err != nil {
 				t.Fatalf(`unexpected error when executing %q: %s`, q, err)
 			}
-			testResultsEqual(t, result, resultExpected)
+			testResultsEqual(t, result, resultExpected, false)
 		}
 	}
 
@@ -9345,10 +9346,10 @@ func TestExecError(t *testing.T) {
 	f := func(q string) {
 		t.Helper()
 		ec := &EvalConfig{
-			AuthToken: &auth.Token{
+			AuthTokens: []*auth.Token{{
 				AccountID: 123,
 				ProjectID: 567,
-			},
+			}},
 			Start:              1000,
 			End:                2000,
 			Step:               100,
@@ -9631,7 +9632,7 @@ func TestExecError(t *testing.T) {
 	f(`rollup_candlestick(time(), "foo")`)
 }
 
-func testResultsEqual(t *testing.T, result, resultExpected []netstorage.Result) {
+func testResultsEqual(t *testing.T, result, resultExpected []netstorage.Result, verifyTenant bool) {
 	t.Helper()
 	if len(result) != len(resultExpected) {
 		t.Fatalf(`unexpected timeseries count; got %d; want %d`, len(result), len(resultExpected))
@@ -9639,17 +9640,17 @@ func testResultsEqual(t *testing.T, result, resultExpected []netstorage.Result)
 	for i := range result {
 		r := &result[i]
 		rExpected := &resultExpected[i]
-		testMetricNamesEqual(t, &r.MetricName, &rExpected.MetricName, i)
+		testMetricNamesEqual(t, &r.MetricName, &rExpected.MetricName, verifyTenant, i)
 		testRowsEqual(t, r.Values, r.Timestamps, rExpected.Values, rExpected.Timestamps)
 	}
 }
 
-func testMetricNamesEqual(t *testing.T, mn, mnExpected *storage.MetricName, pos int) {
+func testMetricNamesEqual(t *testing.T, mn, mnExpected *storage.MetricName, verifyTenant bool, pos int) {
 	t.Helper()
-	if mn.AccountID != mnExpected.AccountID {
+	if verifyTenant && mn.AccountID != mnExpected.AccountID {
 		t.Fatalf(`unexpected accountID; got %d; want %d`, mn.AccountID, mnExpected.AccountID)
 	}
-	if mn.ProjectID != mnExpected.ProjectID {
+	if verifyTenant && mn.ProjectID != mnExpected.ProjectID {
 		t.Fatalf(`unexpected projectID; got %d; want %d`, mn.ProjectID, mnExpected.ProjectID)
 	}
 	if string(mn.MetricGroup) != string(mnExpected.MetricGroup) {

app/vmselect/promql/rollup.go

@@ -369,7 +369,7 @@ func getRollupTag(expr metricsql.Expr) (string, error) {
 }
 
 func getRollupConfigs(funcName string, rf rollupFunc, expr metricsql.Expr, start, end, step int64, maxPointsPerSeries int,
-	window, lookbackDelta int64, sharedTimestamps []int64) (
+	window, lookbackDelta int64, sharedTimestamps []int64, isMultiTenant bool) (
 	func(values []float64, timestamps []int64), []*rollupConfig, error) {
 	preFunc := func(_ []float64, _ []int64) {}
 	funcName = strings.ToLower(funcName)
@@ -395,6 +395,7 @@ func getRollupConfigs(funcName string, rf rollupFunc, expr metricsql.Expr, start
 			Timestamps:            sharedTimestamps,
 			isDefaultRollup:       funcName == "default_rollup",
 			samplesScannedPerCall: samplesScannedPerCall,
+			isMultiTenant:         isMultiTenant,
 		}
 	}
 
@@ -586,6 +587,10 @@ type rollupConfig struct {
 	//
 	// If zero, then it is considered that Func scans all the samples passed to it.
 	samplesScannedPerCall int
+
+	// Whether the rollup is used in multi-tenant mode.
+	// This is used in order to populate labels with tenancy information.
+	isMultiTenant bool
 }
 
 func (rc *rollupConfig) getTimestamps() []int64 {

app/vmselect/promql/rollup_result_cache.go

@@ -9,6 +9,10 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/VictoriaMetrics/fastcache"
+	"github.com/VictoriaMetrics/metrics"
+	"github.com/VictoriaMetrics/metricsql"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/auth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/encoding"
@@ -21,9 +25,6 @@ import (
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/stringsutil"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/workingsetcache"
-	"github.com/VictoriaMetrics/fastcache"
-	"github.com/VictoriaMetrics/metrics"
-	"github.com/VictoriaMetrics/metricsql"
 )
 
 var (
@@ -176,7 +177,6 @@ func (rrc *rollupResultCache) GetInstantValues(qt *querytracer.Tracer, at *auth.
 	// Obtain instant values from the cache
 	bb := bbPool.Get()
 	defer bbPool.Put(bb)
-
 	bb.B = marshalRollupResultCacheKeyForInstantValues(bb.B[:0], at, expr, window, step, etfss)
 	tss, ok := rrc.getSeriesFromCache(qt, bb.B)
 	if !ok || len(tss) == 0 {
@@ -207,7 +207,6 @@ func (rrc *rollupResultCache) PutInstantValues(qt *querytracer.Tracer, at *auth.
 
 	bb := bbPool.Get()
 	defer bbPool.Put(bb)
-
 	bb.B = marshalRollupResultCacheKeyForInstantValues(bb.B[:0], at, expr, window, step, etfss)
 	_ = rrc.putSeriesToCache(qt, bb.B, step, tss)
 }
@@ -215,12 +214,10 @@ func (rrc *rollupResultCache) PutInstantValues(qt *querytracer.Tracer, at *auth.
 func (rrc *rollupResultCache) DeleteInstantValues(qt *querytracer.Tracer, at *auth.Token, expr metricsql.Expr, window, step int64, etfss [][]storage.TagFilter) {
 	bb := bbPool.Get()
 	defer bbPool.Put(bb)
-
 	bb.B = marshalRollupResultCacheKeyForInstantValues(bb.B[:0], at, expr, window, step, etfss)
 	if !rrc.putSeriesToCache(qt, bb.B, step, nil) {
 		logger.Panicf("BUG: cannot store zero series to cache")
 	}
-
 	if qt.Enabled() {
 		query := string(expr.AppendString(nil))
 		query = stringsutil.LimitStringLen(query, 300)
@@ -239,8 +236,12 @@ func (rrc *rollupResultCache) GetSeries(qt *querytracer.Tracer, ec *EvalConfig,
 	// Obtain tss from the cache.
 	bb := bbPool.Get()
 	defer bbPool.Put(bb)
+	at := ec.AuthTokens[0]
+	if ec.IsMultiTenant {
+		at = nil
+	}
 
-	bb.B = marshalRollupResultCacheKeyForSeries(bb.B[:0], ec.AuthToken, expr, window, ec.Step, ec.EnforcedTagFilterss)
+	bb.B = marshalRollupResultCacheKeyForSeries(bb.B[:0], at, expr, window, ec.Step, ec.EnforcedTagFilterss)
 	metainfoBuf := rrc.c.Get(nil, bb.B)
 	if len(metainfoBuf) == 0 {
 		qt.Printf("nothing found")
@@ -262,7 +263,7 @@ func (rrc *rollupResultCache) GetSeries(qt *querytracer.Tracer, ec *EvalConfig,
 	if !ok {
 		mi.RemoveKey(key)
 		metainfoBuf = mi.Marshal(metainfoBuf[:0])
-		bb.B = marshalRollupResultCacheKeyForSeries(bb.B[:0], ec.AuthToken, expr, window, ec.Step, ec.EnforcedTagFilterss)
+		bb.B = marshalRollupResultCacheKeyForSeries(bb.B[:0], ec.AuthTokens[0], expr, window, ec.Step, ec.EnforcedTagFilterss)
 		rrc.c.Set(bb.B, metainfoBuf)
 		return nil, ec.Start
 	}
@@ -368,7 +369,11 @@ func (rrc *rollupResultCache) PutSeries(qt *querytracer.Tracer, ec *EvalConfig,
 	metainfoBuf := bbPool.Get()
 	defer bbPool.Put(metainfoBuf)
 
-	metainfoKey.B = marshalRollupResultCacheKeyForSeries(metainfoKey.B[:0], ec.AuthToken, expr, window, ec.Step, ec.EnforcedTagFilterss)
+	at := ec.AuthTokens[0]
+	if ec.IsMultiTenant {
+		at = nil
+	}
+	metainfoKey.B = marshalRollupResultCacheKeyForSeries(metainfoKey.B[:0], at, expr, window, ec.Step, ec.EnforcedTagFilterss)
 	metainfoBuf.B = rrc.c.Get(metainfoBuf.B[:0], metainfoKey.B)
 	var mi rollupResultCacheMetainfo
 	if len(metainfoBuf.B) > 0 {
@@ -508,8 +513,10 @@ func marshalRollupResultCacheKeyForSeries(dst []byte, at *auth.Token, expr metri
 	dst = append(dst, rollupResultCacheVersion)
 	dst = encoding.MarshalUint64(dst, rollupResultCacheKeyPrefix.Load())
 	dst = append(dst, rollupResultCacheTypeSeries)
-	dst = encoding.MarshalUint32(dst, at.AccountID)
-	dst = encoding.MarshalUint32(dst, at.ProjectID)
+	if at != nil {
+		dst = encoding.MarshalUint32(dst, at.AccountID)
+		dst = encoding.MarshalUint32(dst, at.ProjectID)
+	}
 	dst = encoding.MarshalInt64(dst, window)
 	dst = encoding.MarshalInt64(dst, step)
 	dst = marshalTagFiltersForRollupResultCacheKey(dst, etfs)
@@ -521,8 +528,10 @@ func marshalRollupResultCacheKeyForInstantValues(dst []byte, at *auth.Token, exp
 	dst = append(dst, rollupResultCacheVersion)
 	dst = encoding.MarshalUint64(dst, rollupResultCacheKeyPrefix.Load())
 	dst = append(dst, rollupResultCacheTypeInstantValues)
-	dst = encoding.MarshalUint32(dst, at.AccountID)
-	dst = encoding.MarshalUint32(dst, at.ProjectID)
+	if at != nil {
+		dst = encoding.MarshalUint32(dst, at.AccountID)
+		dst = encoding.MarshalUint32(dst, at.ProjectID)
+	}
 	dst = encoding.MarshalInt64(dst, window)
 	dst = encoding.MarshalInt64(dst, step)
 	dst = marshalTagFiltersForRollupResultCacheKey(dst, etfs)

app/vmselect/promql/rollup_result_cache_test.go

@@ -4,10 +4,11 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/VictoriaMetrics/metricsql"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/auth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/storage"
-	"github.com/VictoriaMetrics/metricsql"
 )
 
 func TestRollupResultCacheInitStop(t *testing.T) {
@@ -40,10 +41,10 @@ func TestRollupResultCache(t *testing.T) {
 		Step:               200,
 		MaxPointsPerSeries: 1e4,
 
-		AuthToken: &auth.Token{
+		AuthTokens: []*auth.Token{{
 			AccountID: 333,
 			ProjectID: 843,
-		},
+		}},
 
 		MayCache: true,
 	}
@@ -322,7 +323,60 @@ func TestRollupResultCache(t *testing.T) {
 		}
 		testTimeseriesEqual(t, tss, tssExpected)
 	})
+	t.Run("multi-tenant cache can be retrieved", func(t *testing.T) {
+		ResetRollupResultCache()
+		tssGolden := []*timeseries{
+			{
+				MetricName: storage.MetricName{
+					AccountID: 0,
+					ProjectID: 0,
+				},
+				Timestamps: []int64{800, 1000, 1200},
+				Values:     []float64{0, 1, 2},
+			},
+			{
+				MetricName: storage.MetricName{
+					AccountID: 0,
+					ProjectID: 1,
+				},
+				Timestamps: []int64{800, 1000, 1200},
+				Values:     []float64{0, 1, 2},
+			},
+			{
+				MetricName: storage.MetricName{
+					AccountID: 1,
+					ProjectID: 1,
+				},
+				Timestamps: []int64{800, 1000, 1200},
+				Values:     []float64{0, 1, 2},
+			},
+		}
+		ecL := copyEvalConfig(ec)
+		ecL.Start = 800
+		ecL.AuthTokens = []*auth.Token{
+			{
+				AccountID: 0,
+				ProjectID: 0,
+			},
+			{
+				AccountID: 0,
+				ProjectID: 1,
+			},
+			{
+				AccountID: 1,
+				ProjectID: 1,
+			},
+		}
+		ecL.IsMultiTenant = true
+		rollupResultCacheV.PutSeries(nil, ecL, fe, window, tssGolden)
 
+		tss, newStart := rollupResultCacheV.GetSeries(nil, ecL, fe, window)
+		if newStart != 1400 {
+			t.Fatalf("unexpected newStart; got %d; want %d", newStart, 1400)
+		}
+
+		testTimeseriesEqual(t, tss, tssGolden)
+	})
 }
 
 func TestMergeSeries(t *testing.T) {
@@ -511,7 +565,7 @@ func testTimeseriesEqual(t *testing.T, tss, tssExpected []*timeseries) {
 	}
 	for i, ts := range tss {
 		tsExpected := tssExpected[i]
-		testMetricNamesEqual(t, &ts.MetricName, &tsExpected.MetricName, i)
+		testMetricNamesEqual(t, &ts.MetricName, &tsExpected.MetricName, true, i)
 		testRowsEqual(t, ts.Values, ts.Timestamps, tsExpected.Values, tsExpected.Timestamps)
 	}
 }

app/vmselect/promql/timeseries.go

@@ -287,8 +287,9 @@ func marshalMetricTagsFast(dst []byte, tags []storage.Tag) []byte {
 }
 
 func marshalMetricNameSorted(dst []byte, mn *storage.MetricName) []byte {
-	// Do not marshal AccountID and ProjectID, since they are unused.
 	dst = marshalBytesFast(dst, mn.MetricGroup)
+	dst = encoding.MarshalUint32(dst, mn.AccountID)
+	dst = encoding.MarshalUint32(dst, mn.ProjectID)
 	return marshalMetricTagsSorted(dst, mn)
 }
 

app/vmselect/querystats/querystats.go

@@ -36,6 +36,14 @@ func RegisterQuery(accountID, projectID uint32, query string, timeRangeMsecs int
 	qsTracker.registerQuery(accountID, projectID, query, timeRangeMsecs, startTime)
 }
 
+// RegisterQueryMultiTenant registers the query on the given timeRangeMsecs, which has been started at startTime.
+//
+// RegisterQueryMultiTenant must be called when the query is finished.
+func RegisterQueryMultiTenant(query string, timeRangeMsecs int64, startTime time.Time) {
+	initOnce.Do(initQueryStats)
+	qsTracker.registerQueryMultiTenant(query, timeRangeMsecs, startTime)
+}
+
 // WriteJSONQueryStats writes query stats to given writer in json format.
 func WriteJSONQueryStats(w io.Writer, topN int, maxLifetime time.Duration) {
 	initOnce.Do(initQueryStats)
@@ -66,6 +74,7 @@ type queryStatRecord struct {
 	timeRangeSecs int64
 	registerTime  time.Time
 	duration      time.Duration
+	multiTenant   bool
 }
 
 type queryStatKey struct {
@@ -73,6 +82,7 @@ type queryStatKey struct {
 	projectID     uint32
 	query         string
 	timeRangeSecs int64
+	multiTenant   bool
 }
 
 type accountProjectFilter struct {
@@ -100,7 +110,7 @@ func (qst *queryStatsTracker) writeJSONQueryStats(w io.Writer, topN int, apFilte
 	fmt.Fprintf(w, `"topByCount":[`)
 	topByCount := qst.getTopByCount(topN, apFilter, maxLifetime)
 	for i, r := range topByCount {
-		fmt.Fprintf(w, `{"accountID":%d,"projectID":%d,"query":%s,"timeRangeSeconds":%d,"count":%d}`, r.accountID, r.projectID, stringsutil.JSONString(r.query), r.timeRangeSecs, r.count)
+		fmt.Fprintf(w, `{"accountID":%d,"projectID":%d,"query":%s,"timeRangeSeconds":%d,"count":%d,"multiTenant":%v}`, r.accountID, r.projectID, stringsutil.JSONString(r.query), r.timeRangeSecs, r.count, r.multiTenant)
 		if i+1 < len(topByCount) {
 			fmt.Fprintf(w, `,`)
 		}
@@ -108,8 +118,8 @@ func (qst *queryStatsTracker) writeJSONQueryStats(w io.Writer, topN int, apFilte
 	fmt.Fprintf(w, `],"topByAvgDuration":[`)
 	topByAvgDuration := qst.getTopByAvgDuration(topN, apFilter, maxLifetime)
 	for i, r := range topByAvgDuration {
-		fmt.Fprintf(w, `{"accountID":%d,"projectID":%d,"query":%s,"timeRangeSeconds":%d,"avgDurationSeconds":%.3f,"count":%d}`,
-			r.accountID, r.projectID, stringsutil.JSONString(r.query), r.timeRangeSecs, r.duration.Seconds(), r.count)
+		fmt.Fprintf(w, `{"accountID":%d,"projectID":%d,"query":%s,"timeRangeSeconds":%d,"avgDurationSeconds":%.3f,"count":%d,"multiTenant": %v}`,
+			r.accountID, r.projectID, stringsutil.JSONString(r.query), r.timeRangeSecs, r.duration.Seconds(), r.count, r.multiTenant)
 		if i+1 < len(topByAvgDuration) {
 			fmt.Fprintf(w, `,`)
 		}
@@ -117,8 +127,8 @@ func (qst *queryStatsTracker) writeJSONQueryStats(w io.Writer, topN int, apFilte
 	fmt.Fprintf(w, `],"topBySumDuration":[`)
 	topBySumDuration := qst.getTopBySumDuration(topN, apFilter, maxLifetime)
 	for i, r := range topBySumDuration {
-		fmt.Fprintf(w, `{"accountID":%d,"projectID":%d,"query":%s,"timeRangeSeconds":%d,"sumDurationSeconds":%.3f,"count":%d}`,
-			r.accountID, r.projectID, stringsutil.JSONString(r.query), r.timeRangeSecs, r.duration.Seconds(), r.count)
+		fmt.Fprintf(w, `{"accountID":%d,"projectID":%d,"query":%s,"timeRangeSeconds":%d,"sumDurationSeconds":%.3f,"count":%d,"multiTenant":%v}`,
+			r.accountID, r.projectID, stringsutil.JSONString(r.query), r.timeRangeSecs, r.duration.Seconds(), r.count, r.multiTenant)
 		if i+1 < len(topBySumDuration) {
 			fmt.Fprintf(w, `,`)
 		}
@@ -151,6 +161,30 @@ func (qst *queryStatsTracker) registerQuery(accountID, projectID uint32, query s
 	r.duration = duration
 }
 
+func (qst *queryStatsTracker) registerQueryMultiTenant(query string, timeRangeMsecs int64, startTime time.Time) {
+	registerTime := time.Now()
+	duration := registerTime.Sub(startTime)
+	if duration < *minQueryDuration {
+		return
+	}
+
+	qst.mu.Lock()
+	defer qst.mu.Unlock()
+
+	a := qst.a
+	idx := qst.nextIdx
+	if idx >= uint(len(a)) {
+		idx = 0
+	}
+	qst.nextIdx = idx + 1
+	r := &a[idx]
+	r.multiTenant = true
+	r.query = query
+	r.timeRangeSecs = timeRangeMsecs / 1000
+	r.registerTime = registerTime
+	r.duration = duration
+}
+
 func (r *queryStatRecord) matches(apFilter *accountProjectFilter, currentTime time.Time, maxLifetime time.Duration) bool {
 	if r.query == "" || currentTime.Sub(r.registerTime) > maxLifetime {
 		return false
@@ -167,6 +201,7 @@ func (r *queryStatRecord) key() queryStatKey {
 		projectID:     r.projectID,
 		query:         r.query,
 		timeRangeSecs: r.timeRangeSecs,
+		multiTenant:   r.multiTenant,
 	}
 }
 
@@ -190,6 +225,7 @@ func (qst *queryStatsTracker) getTopByCount(topN int, apFilter *accountProjectFi
 			query:         k.query,
 			timeRangeSecs: k.timeRangeSecs,
 			count:         count,
+			multiTenant:   k.multiTenant,
 		})
 	}
 	sort.Slice(a, func(i, j int) bool {
@@ -207,6 +243,7 @@ type queryStatByCount struct {
 	query         string
 	timeRangeSecs int64
 	count         int
+	multiTenant   bool
 }
 
 func (qst *queryStatsTracker) getTopByAvgDuration(topN int, apFilter *accountProjectFilter, maxLifetime time.Duration) []queryStatByDuration {
@@ -237,6 +274,7 @@ func (qst *queryStatsTracker) getTopByAvgDuration(topN int, apFilter *accountPro
 			timeRangeSecs: k.timeRangeSecs,
 			duration:      ks.sum / time.Duration(ks.count),
 			count:         ks.count,
+			multiTenant:   k.multiTenant,
 		})
 	}
 	sort.Slice(a, func(i, j int) bool {
@@ -255,6 +293,7 @@ type queryStatByDuration struct {
 	timeRangeSecs int64
 	duration      time.Duration
 	count         int
+	multiTenant   bool
 }
 
 func (qst *queryStatsTracker) getTopBySumDuration(topN int, apFilter *accountProjectFilter, maxLifetime time.Duration) []queryStatByDuration {
@@ -285,6 +324,7 @@ func (qst *queryStatsTracker) getTopBySumDuration(topN int, apFilter *accountPro
 			timeRangeSecs: k.timeRangeSecs,
 			duration:      kd.sum,
 			count:         kd.count,
+			multiTenant:   k.multiTenant,
 		})
 	}
 	sort.Slice(a, func(i, j int) bool {

docs/Cluster-VictoriaMetrics.md

@@ -113,8 +113,55 @@ such as [Graphite](https://docs.victoriametrics.com/#how-to-send-data-from-graph
 [InfluxDB line protocol via TCP and UDP](https://docs.victoriametrics.com/#how-to-send-data-from-influxdb-compatible-agents-such-as-telegraf) and
 [OpenTSDB telnet put protocol](https://docs.victoriametrics.com/#sending-data-via-telnet-put-protocol).
 
+
+`vmselect` can execute queries over multiple [tenants](#multitenancy) via special `multitenant` endpoints `http://vmselect:8481/select/multitenant/<suffix>`.
+Currently supported endpoints for `<suffix>` are:
+- `/prometheus/api/v1/query`
+- `/prometheus/api/v1/query_range`
+- `/prometheus/api/v1/series`
+- `/prometheus/api/v1/labels`
+- `/prometheus/api/v1/label/<label_name>/values`
+- `/prometheus/api/v1/status/active_queries`
+- `/prometheus/api/v1/status/top_queries`
+- `/prometheus/api/v1/status/tsdb`
+- `/prometheus/api/v1/export`
+- `/prometheus/api/v1/export/csv`
+- `/vmui`
+
+It is possible to explicitly specify `accountID` and `projectID` for querying multiple tenants via `vm_account_id` and `vm_project_id` labels in the query.
+Alternatively, it is possible to use [`extra_filters[]` and `extra_label`](https://docs.victoriametrics.com/#prometheus-querying-api-enhancements)
+query args to apply additional filters for the query.
+
+For example, the following query fetches the total number of time series for the tenants `accountID=42` and `accountID=7, projectID=9`:
+```
+up{vm_account_id="7", vm_project_id="9" or vm_account_id="42"}
+```
+
+In order to achieve the same via `extra_filters[]` and `extra_label` query args, the following query must be used:
+```
+curl 'http://vmselect:8481/select/multitenant/prometheus/api/v1/query' \
+  -d 'query=up' \
+  -d 'extra_filters[]={vm_account_id="7",vm_project_id="9"}' \
+  -d 'extra_filters[]={vm_account_id="42"}'
+```
+
+The precedence for applying filters for tenants follows this order:
+
+1. filters tenants from `extra_label` and `extra_filters` query arguments label selectors.
+ These filters have the highest priority and are applied first when provided through the query arguments.
+
+2. filters tenants from labels selectors defined at metricsQL query expression.
+
+
+
+Note that `vm_account_id` and `vm_project_id` labels support all operators for label matching. For example:
+```
+up{vm_account_id!="42"} # selects all the time series except those belonging to accountID=42
+up{vm_account_id=~"4.*"} # selects all the time series belonging to accountIDs starting with 4
+```
+
 **Security considerations:** it is recommended restricting access to `multitenant` endpoints only to trusted sources,
-since untrusted source may break per-tenant data by writing unwanted samples to arbitrary tenants.
+since untrusted source may break per-tenant data by writing unwanted samples or get access to data of arbitrary tenants.
 
 
 ## Binaries
@@ -1596,6 +1643,8 @@ Below is the output for `/path/to/vmselect -help`:
   -search.inmemoryBufSizeBytes size
      Size for in-memory data blocks used during processing search requests. By default, the size is automatically calculated based on available memory. Adjust this flag value if you observe that vm_tmp_blocks_max_inmemory_file_size_bytes metric constantly shows much higher values than vm_tmp_blocks_inmemory_file_size_bytes. See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/6851
      Supports the following optional suffixes for size values: KB, MB, GB, TB, KiB, MiB, GiB, TiB (default 0)
+  -search.tenantCacheExpireDuration duration
+     The expiry duration for list of tenants for multi-tenant queries. (default 5m0s)
   -search.treatDotsAsIsInRegexps
      Whether to treat dots as is in regexp label filters used in queries. For example, foo{bar=~"a.b.c"} will be automatically converted to foo{bar=~"a\\.b\\.c"}, i.e. all the dots in regexp filters will be automatically escaped in order to match only dot char instead of matching any char. Dots in ".+", ".*" and ".{n}" regexps aren't escaped. This option is DEPRECATED in favor of {__graphite__="a.*.c"} syntax for selecting metrics matching the given Graphite metrics filter
   -selectNode array

lib/auth/auth.go

@@ -44,25 +44,35 @@ func NewTokenPossibleMultitenant(authToken string) (*Token, error) {
 
 // Init initializes t from authToken.
 func (t *Token) Init(authToken string) error {
+	accountID, projectID, err := ParseToken(authToken)
+	if err != nil {
+		return fmt.Errorf("cannot parse authToken %q: %w", authToken, err)
+	}
+
+	t.Set(accountID, projectID)
+	return nil
+}
+
+// ParseToken parses authToken and returns accountID and projectID from it.
+func ParseToken(authToken string) (uint32, uint32, error) {
 	tmp := strings.Split(authToken, ":")
 	if len(tmp) > 2 {
-		return fmt.Errorf("unexpected number of items in authToken %q; got %d; want 1 or 2", authToken, len(tmp))
+		return 0, 0, fmt.Errorf("unexpected number of items in authToken %q; got %d; want 1 or 2", authToken, len(tmp))
 	}
 	n, err := strconv.ParseUint(tmp[0], 10, 32)
 	if err != nil {
-		return fmt.Errorf("cannot parse accountID from %q: %w", tmp[0], err)
+		return 0, 0, fmt.Errorf("cannot parse accountID from %q: %w", tmp[0], err)
 	}
 	accountID := uint32(n)
 	projectID := uint32(0)
 	if len(tmp) > 1 {
 		n, err := strconv.ParseUint(tmp[1], 10, 32)
 		if err != nil {
-			return fmt.Errorf("cannot parse projectID from %q: %w", tmp[1], err)
+			return 0, 0, fmt.Errorf("cannot parse projectID from %q: %w", tmp[1], err)
 		}
 		projectID = uint32(n)
 	}
-	t.Set(accountID, projectID)
-	return nil
+	return accountID, projectID, nil
 }
 
 // Set sets accountID and projectID for the t.

lib/storage/search.go

@@ -277,6 +277,9 @@ type SearchQuery struct {
 	AccountID uint32
 	ProjectID uint32
 
+	TenantTokens  []TenantToken
+	IsMultiTenant bool
+
 	// The time range for searching time series
 	MinTimestamp int64
 	MaxTimestamp int64
@@ -306,12 +309,53 @@ func NewSearchQuery(accountID, projectID uint32, start, end int64, tagFilterss [
 		maxMetrics = 2e9
 	}
 	return &SearchQuery{
-		AccountID:    accountID,
-		ProjectID:    projectID,
 		MinTimestamp: start,
 		MaxTimestamp: end,
 		TagFilterss:  tagFilterss,
 		MaxMetrics:   maxMetrics,
+		TenantTokens: []TenantToken{
+			{
+				AccountID: accountID,
+				ProjectID: projectID,
+			},
+		},
+	}
+}
+
+// TenantToken represents a tenant (accountID, projectID) pair.
+type TenantToken struct {
+	AccountID uint32
+	ProjectID uint32
+}
+
+// String returns string representation of t.
+func (t *TenantToken) String() string {
+	return fmt.Sprintf("{accountID=%d, projectID=%d}", t.AccountID, t.ProjectID)
+}
+
+// Marshal appends marshaled t to dst and returns the result.
+func (t *TenantToken) Marshal(dst []byte) []byte {
+	dst = encoding.MarshalUint32(dst, t.AccountID)
+	dst = encoding.MarshalUint32(dst, t.ProjectID)
+	return dst
+}
+
+// NewMultiTenantSearchQuery creates new search query for the given args.
+func NewMultiTenantSearchQuery(tenants []TenantToken, start, end int64, tagFilterss [][]TagFilter, maxMetrics int) *SearchQuery {
+	if start < 0 {
+		// This is needed for https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5553
+		start = 0
+	}
+	if maxMetrics <= 0 {
+		maxMetrics = 2e9
+	}
+	return &SearchQuery{
+		TenantTokens:  tenants,
+		MinTimestamp:  start,
+		MaxTimestamp:  end,
+		TagFilterss:   tagFilterss,
+		MaxMetrics:    maxMetrics,
+		IsMultiTenant: true,
 	}
 }
 
@@ -412,7 +456,15 @@ func (sq *SearchQuery) String() string {
 	}
 	start := TimestampToHumanReadableFormat(sq.MinTimestamp)
 	end := TimestampToHumanReadableFormat(sq.MaxTimestamp)
-	return fmt.Sprintf("accountID=%d, projectID=%d, filters=%s, timeRange=[%s..%s]", sq.AccountID, sq.ProjectID, a, start, end)
+	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)
 }
 
 func tagFiltersToString(tfs []TagFilter) string {
@@ -423,10 +475,9 @@ 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 {
-	dst = encoding.MarshalUint32(dst, sq.AccountID)
-	dst = encoding.MarshalUint32(dst, sq.ProjectID)
+// MarshaWithoutTenant 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) MarshaWithoutTenant(dst []byte) []byte {
 	dst = encoding.MarshalVarInt64(dst, sq.MinTimestamp)
 	dst = encoding.MarshalVarInt64(dst, sq.MaxTimestamp)
 	dst = encoding.MarshalVarUint64(dst, uint64(len(sq.TagFilterss)))

lib/storage/search_test.go

@@ -29,7 +29,12 @@ 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.MarshaWithoutTenant(buf)
 
 		tail, err := sq2.Unmarshal(buf)
 		if err != nil {

lib/tenantmetrics/counter_map.go

@@ -4,9 +4,10 @@ import (
 	"fmt"
 	"sync/atomic"
 
+	"github.com/VictoriaMetrics/metrics"
+
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/auth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
-	"github.com/VictoriaMetrics/metrics"
 )
 
 // TenantID defines metric tenant.
@@ -21,6 +22,8 @@ type CounterMap struct {
 
 	// do not use atomic.Pointer, since the stored map there is already a pointer type.
 	m atomic.Value
+	// mt holds value for multi-tenant metrics.
+	mt atomic.Value
 }
 
 // NewCounterMap creates new CounterMap for the given metric.
@@ -34,11 +37,15 @@ func NewCounterMap(metric string) *CounterMap {
 
 // Get returns counter for the given at
 func (cm *CounterMap) Get(at *auth.Token) *metrics.Counter {
+	if at == nil {
+		return cm.GetByTenant(nil)
+	}
+
 	key := TenantID{
 		AccountID: at.AccountID,
 		ProjectID: at.ProjectID,
 	}
-	return cm.GetByTenant(key)
+	return cm.GetByTenant(&key)
 }
 
 // MultiAdd adds multiple values grouped by auth.Token
@@ -49,9 +56,19 @@ func (cm *CounterMap) MultiAdd(perTenantValues map[auth.Token]int) {
 }
 
 // GetByTenant returns counter for the given key.
-func (cm *CounterMap) GetByTenant(key TenantID) *metrics.Counter {
+func (cm *CounterMap) GetByTenant(key *TenantID) *metrics.Counter {
+	if key == nil {
+		mtm := cm.mt.Load()
+		if mtm == nil {
+			mtc := metrics.GetOrCreateCounter(createMetricNameMultitenant(cm.metric))
+			cm.mt.Store(mtc)
+			return mtc
+		}
+		return mtm.(*metrics.Counter)
+	}
+
 	m := cm.m.Load().(map[TenantID]*metrics.Counter)
-	if c := m[key]; c != nil {
+	if c := m[*key]; c != nil {
 		// Fast path - the counter for k already exists.
 		return c
 	}
@@ -61,9 +78,9 @@ func (cm *CounterMap) GetByTenant(key TenantID) *metrics.Counter {
 	for k, c := range m {
 		newM[k] = c
 	}
-	metricName := createMetricName(cm.metric, key)
+	metricName := createMetricName(cm.metric, *key)
 	c := metrics.GetOrCreateCounter(metricName)
-	newM[key] = c
+	newM[*key] = c
 	cm.m.Store(newM)
 	return c
 }
@@ -79,3 +96,15 @@ func createMetricName(metric string, key TenantID) string {
 	// Metric with labels.
 	return fmt.Sprintf(`%s,accountID="%d",projectID="%d"}`, metric[:len(metric)-1], key.AccountID, key.ProjectID)
 }
+
+func createMetricNameMultitenant(metric string) string {
+	if len(metric) == 0 {
+		logger.Panicf("BUG: metric cannot be empty")
+	}
+	if metric[len(metric)-1] != '}' {
+		// Metric without labels.
+		return fmt.Sprintf(`%s{accountID="multitenant",projectID="multitenant"}`, metric)
+	}
+	// Metric with labels.
+	return fmt.Sprintf(`%s,accountID="multitenant",projectID="multitenant"}`, metric[:len(metric)-1])
+}

lib/timeutil/timeutil.go

@@ -17,3 +17,15 @@ func AddJitterToDuration(d time.Duration) time.Duration {
 	p := float64(fastrand.Uint32()) / (1 << 32)
 	return d + time.Duration(p*float64(dv))
 }
+
+// StartOfDay returns the start of the day for the given timestamp.
+// Timestamp is in milliseconds.
+func StartOfDay(ts int64) int64 {
+	return ts - (ts % 86400000)
+}
+
+// EndOfDay returns the end of the day for the given timestamp.
+// Timestamp is in milliseconds.
+func EndOfDay(ts int64) int64 {
+	return StartOfDay(ts) + 86400000 - 1
+}

lib/timeutil/timeutil_test.go

@@ -25,3 +25,45 @@ func TestAddJitterToDuration(t *testing.T) {
 	f(time.Hour)
 	f(24 * time.Hour)
 }
+
+func TestStartOfDay(t *testing.T) {
+	f := func(original, expected time.Time) {
+		t.Helper()
+
+		result := StartOfDay(original.UnixMilli())
+		if result != expected.UnixMilli() {
+			t.Fatalf("unexpected result; got %d; want %d", result, expected.UnixMilli())
+		}
+	}
+
+	f(
+		time.Date(2021, 1, 1, 1, 1, 1, 0, time.UTC),
+		time.Date(2021, 1, 1, 0, 0, 0, 0, time.UTC),
+	)
+
+	f(
+		time.Date(2021, 1, 1, 23, 59, 59, 999999999, time.UTC),
+		time.Date(2021, 1, 1, 0, 0, 0, 0, time.UTC),
+	)
+}
+
+func TestEndOfDay(t *testing.T) {
+	f := func(original, expected time.Time) {
+		t.Helper()
+
+		result := EndOfDay(original.UnixMilli())
+		if result != expected.UnixMilli() {
+			t.Fatalf("unexpected result; got %d; want %d", result, expected.UnixMilli())
+		}
+	}
+
+	f(
+		time.Date(2021, 1, 1, 1, 1, 1, 0, time.UTC),
+		time.Date(2021, 1, 1, 23, 59, 59, 999999999, time.UTC),
+	)
+
+	f(
+		time.Date(2021, 1, 1, 23, 59, 59, 999999999, time.UTC),
+		time.Date(2021, 1, 1, 23, 59, 59, 999999999, time.UTC),
+	)
+}