logstorage: support GetTenants low level API

lib/logstorage/indexdb.go

@@ -470,6 +470,47 @@ func (is *indexSearch) getStreamIDsForTagRegexp(tenantID TenantID, tagName strin
 	return ids
 }
 
+func (is *indexSearch) getTenantIDs() []TenantID {
+	var tenantIDs []TenantID // return as result
+	var tenantID TenantID    // variable for unmarshal
+
+	ts := &is.ts
+	kb := &is.kb
+
+	kb.B = marshalCommonPrefix(kb.B[:0], nsPrefixStreamID, tenantID)
+	ts.Seek(kb.B)
+
+	for ts.NextItem() {
+		_, prefix, err := unmarshalCommonPrefix(&tenantID, ts.Item)
+		if err != nil {
+			logger.Panicf("FATAL: cannot unmarshal tenantID: %s", err)
+		}
+		if prefix != nsPrefixStreamID {
+			// Reached the end of entries with the needed prefix.
+			break
+		}
+		tenantIDs = append(tenantIDs, tenantID)
+		// Seek for the next (accountID, projectID)
+		tenantID.ProjectID++
+		if tenantID.ProjectID == 0 {
+			tenantID.AccountID++
+			if tenantID.AccountID == 0 {
+				// Reached the end (accountID, projectID) space
+				break
+			}
+		}
+
+		kb.B = marshalCommonPrefix(kb.B[:0], nsPrefixStreamID, tenantID)
+		ts.Seek(kb.B)
+	}
+
+	if err := ts.Error(); err != nil {
+		logger.Panicf("FATAL: error when searching for tenant ids: %s", err)
+	}
+
+	return tenantIDs
+}
+
 func (idb *indexdb) mustRegisterStream(streamID *streamID, streamTagsCanonical string) {
 	st := GetStreamTags()
 	mustUnmarshalStreamTags(st, streamTagsCanonical)
@@ -575,6 +616,13 @@ func (idb *indexdb) storeStreamIDsToCache(tenantIDs []TenantID, sf *StreamFilter
 	bbPool.Put(bb)
 }
 
+func (idb *indexdb) searchTenants() []TenantID {
+	is := idb.getIndexSearch()
+	defer idb.putIndexSearch(is)
+
+	return is.getTenantIDs()
+}
+
 type batchItems struct {
 	buf []byte
 

lib/logstorage/indexdb_test.go

@@ -252,3 +252,70 @@ func TestStorageSearchStreamIDs(t *testing.T) {
 
 	closeTestStorage(s)
 }
+
+func TestGetTenantsIDs(t *testing.T) {
+	t.Parallel()
+
+	path := t.Name()
+	const partitionName = "foobar"
+
+	s := newTestStorage()
+	defer closeTestStorage(s)
+
+	mustCreateIndexdb(path)
+	defer fs.MustRemoveDir(path)
+
+	idb := mustOpenIndexdb(path, partitionName, s)
+	defer mustCloseIndexdb(idb)
+
+	tenantIDs := []TenantID{
+		{AccountID: 0, ProjectID: 0},
+		{AccountID: 0, ProjectID: 1},
+		{AccountID: 1, ProjectID: 0},
+		{AccountID: 1, ProjectID: 1},
+		{AccountID: 123, ProjectID: 567},
+	}
+	getStreamIDForTags := func(tags map[string]string) ([]streamID, string) {
+		st := GetStreamTags()
+		for k, v := range tags {
+			st.Add(k, v)
+		}
+		streamTagsCanonical := st.MarshalCanonical(nil)
+		PutStreamTags(st)
+		id := hash128(streamTagsCanonical)
+		sids := make([]streamID, 0, len(tenantIDs))
+		for _, tenantID := range tenantIDs {
+			sid := streamID{
+				tenantID: tenantID,
+				id:       id,
+			}
+
+			sids = append(sids, sid)
+		}
+
+		return sids, string(streamTagsCanonical)
+	}
+
+	// Create indexdb entries
+	const jobsCount = 7
+	const instancesCount = 5
+	for i := 0; i < jobsCount; i++ {
+		for j := 0; j < instancesCount; j++ {
+			sids, streamTagsCanonical := getStreamIDForTags(map[string]string{
+				"job":      fmt.Sprintf("job-%d", i),
+				"instance": fmt.Sprintf("instance-%d", j),
+			})
+			for _, sid := range sids {
+				idb.mustRegisterStream(&sid, streamTagsCanonical)
+			}
+
+		}
+	}
+	idb.debugFlush()
+
+	// run the test
+	result := idb.searchTenants()
+	if !reflect.DeepEqual(result, tenantIDs) {
+		t.Fatalf("unexpected tensntIds; got %v; want %v", result, tenantIDs)
+	}
+}

lib/logstorage/storage_search.go

@@ -587,6 +587,86 @@ func (s *Storage) GetStreamIDs(qctx *QueryContext, limit uint64) ([]ValueWithHit
 	return s.GetFieldValues(qctx, "_stream_id", limit)
 }
 
+// GetTenantIDs returns tenantIDs for the given start and end.
+func (s *Storage) GetTenantIDs(ctx context.Context, start, end int64) ([]TenantID, error) {
+	return s.getTenantIDs(ctx, start, end)
+}
+
+func (s *Storage) getTenantIDs(ctx context.Context, start, end int64) ([]TenantID, error) {
+	workersCount := cgroup.AvailableCPUs()
+	stopCh := ctx.Done()
+
+	tenantIDByWorker := make([][]TenantID, workersCount)
+
+	// spin up workers
+	var wg sync.WaitGroup
+	workCh := make(chan *partition, workersCount)
+	for i := 0; i < workersCount; i++ {
+		wg.Add(1)
+		go func(workerID uint) {
+			defer wg.Done()
+			for pt := range workCh {
+				if needStop(stopCh) {
+					// The search has been canceled. Just skip all the scheduled work in order to save CPU time.
+					continue
+				}
+				tenantIDs := pt.idb.searchTenants()
+				tenantIDByWorker[workerID] = append(tenantIDByWorker[workerID], tenantIDs...)
+			}
+		}(uint(i))
+	}
+
+	// Select partitions according to the selected time range
+	s.partitionsLock.Lock()
+	ptws := s.partitions
+	minDay := start / nsecsPerDay
+	n := sort.Search(len(ptws), func(i int) bool {
+		return ptws[i].day >= minDay
+	})
+	ptws = ptws[n:]
+	maxDay := end / nsecsPerDay
+	n = sort.Search(len(ptws), func(i int) bool {
+		return ptws[i].day > maxDay
+	})
+	ptws = ptws[:n]
+
+	// Copy the selected partitions, so they don't interfere with s.partitions.
+	ptws = append([]*partitionWrapper{}, ptws...)
+
+	for _, ptw := range ptws {
+		ptw.incRef()
+	}
+	s.partitionsLock.Unlock()
+
+	// Schedule concurrent search across matching partitions.
+	for _, ptw := range ptws {
+		workCh <- ptw.pt
+	}
+
+	// Wait until workers finish their work
+	close(workCh)
+	wg.Wait()
+
+	// Decrement references to partitions
+	for _, ptw := range ptws {
+		ptw.decRef()
+	}
+
+	uniqTenantIDs := make(map[TenantID]struct{})
+	for _, tenantIDs := range tenantIDByWorker {
+		for _, tenantID := range tenantIDs {
+			uniqTenantIDs[tenantID] = struct{}{}
+		}
+	}
+
+	tenants := make([]TenantID, 0, len(uniqTenantIDs))
+	for k := range uniqTenantIDs {
+		tenants = append(tenants, k)
+	}
+
+	return tenants, nil
+}
+
 func (s *Storage) runValuesWithHitsQuery(qctx *QueryContext) ([]ValueWithHits, error) {
 	var results []ValueWithHits
 	var resultsLock sync.Mutex

lib/logstorage/storage_search_test.go

@@ -605,6 +605,22 @@ func TestStorageRunQuery(t *testing.T) {
 		}
 	})
 
+	t.Run("tenant_ids", func(t *testing.T) {
+		tenantIDs, err := s.GetTenantIDs(context.TODO(), 0, time.Now().UnixNano())
+		if err != nil {
+			t.Fatalf("unexpected error: %s", err)
+		}
+		sort.Slice(tenantIDs, func(i, j int) bool {
+			return tenantIDs[i].less(&tenantIDs[j])
+		})
+		sort.Slice(allTenantIDs, func(i, j int) bool {
+			return allTenantIDs[i].less(&allTenantIDs[j])
+		})
+		if !reflect.DeepEqual(tenantIDs, allTenantIDs) {
+			t.Fatalf("unexpected GetTenantIDs result; got: %v, want: %v", tenantIDs, allTenantIDs)
+		}
+	})
+
 	// Run more complex tests
 	f := func(t *testing.T, query string, rowsExpected [][]Field) {
 		t.Helper()