ozontech · eguguchkin · Jun 23, 2025 · Sep 18, 2025
diff --git a/bytespool/writer.go b/bytespool/writer.go
@@ -29,15 +29,18 @@ func AcquireWriterSize(out io.Writer, size int) *Writer {
 	}
 }
 
-func FlushReleaseWriter(w *Writer) error {
-	err := w.Flush()
-	if err != nil {
-		return err
-	}
+func ReleaseWriter(w *Writer) {
 	Release(w.Buf)
 	w.Buf = nil
 	w.out = nil
 	writerPool.Put(w)
+}
+
+func FlushReleaseWriter(w *Writer) error {
+	if err := w.Flush(); err != nil {
+		return err
+	}
+	ReleaseWriter(w)
 	return nil
 }
 

diff --git a/cmd/distribution/main.go b/cmd/distribution/main.go
@@ -11,7 +11,8 @@ import (
 
 	"github.com/ozontech/seq-db/cache"
 	"github.com/ozontech/seq-db/consts"
-	"github.com/ozontech/seq-db/frac"
+	"github.com/ozontech/seq-db/frac/common"
+	"github.com/ozontech/seq-db/frac/sealed"
 	"github.com/ozontech/seq-db/fracmanager"
 	"github.com/ozontech/seq-db/logger"
 	"github.com/ozontech/seq-db/seq"
@@ -58,7 +59,7 @@ func readBlock(reader storage.IndexReader, blockIndex uint32) ([]byte, error) {
 	return data, nil
 }
 
-func loadInfo(path string) *frac.Info {
+func loadInfo(path string) *common.Info {
 	indexReader, f := getReader(path)
 	result, err := readBlock(indexReader, 0)
 	if err != nil {
@@ -69,7 +70,7 @@ func loadInfo(path string) *frac.Info {
 		logger.Fatal("seq-db index file header corrupted", zap.String("file", path))
 	}
 
-	b := frac.BlockInfo{}
+	b := sealed.BlockInfo{}
 	err = b.Unpack(result)
 	if err != nil {
 		logger.Fatal("can't unpack info bloc of index file", zap.String("file", path), zap.Error(err))
@@ -84,7 +85,7 @@ func loadInfo(path string) *frac.Info {
 	return b.Info
 }
 
-func buildDist(dist *seq.MIDsDistribution, path string, _ *frac.Info) {
+func buildDist(dist *seq.MIDsDistribution, path string, _ *common.Info) {
 	blocksReader, _ := getReader(path)
 
 	// skip tokens
@@ -160,7 +161,7 @@ func main() {
 		}
 	}
 
-	fc := fracmanager.NewSealedFracCache(filePathDist)
+	fc := fracmanager.NewFracInfoCache(filePathDist)
 
 	lastSavedTime := time.Now()
 	for _, path := range getAllFracs(dataDir) {
@@ -169,7 +170,7 @@ func main() {
 
 		logger.Info("start process", zap.String("name", key))
 
-		info, ok := fc.GetFracInfo(key)
+		info, ok := fc.Get(key)
 		if ok {
 			logger.Info("found in frac-cache", zap.String("key", key))
 		} else {
@@ -197,7 +198,7 @@ func main() {
 		}
 
 		buildDist(info.Distribution, path, info)
-		fc.AddFraction(key, info)
+		fc.Add(info)
 		logger.Info("built distribution", zap.Int("affected_minutes", len(info.Distribution.GetDist())))
 		printDistribution(info.Distribution)
 

diff --git a/cmd/index_analyzer/main.go b/cmd/index_analyzer/main.go
@@ -5,12 +5,13 @@ import (
 	"fmt"
 	"hash/fnv"
 	"os"
+	"sync"
 	"time"
 
 	"github.com/alecthomas/units"
 	"go.uber.org/zap"
 
-	"github.com/ozontech/seq-db/frac"
+	"github.com/ozontech/seq-db/frac/sealed"
 	"github.com/ozontech/seq-db/frac/sealed/lids"
 	"github.com/ozontech/seq-db/frac/sealed/token"
 	"github.com/ozontech/seq-db/fracmanager"
@@ -57,7 +58,15 @@ func main() {
 func getCacheMaintainer() (*fracmanager.CacheMaintainer, func()) {
 	done := make(chan struct{})
 	cm := fracmanager.NewCacheMaintainer(uint64(units.GiB), uint64(units.MiB*64), nil)
-	wg := cm.RunCleanLoop(done, time.Second, time.Second)
+
+	wg := sync.WaitGroup{}
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		cm.RunCleanLoop(done, time.Second, time.Second)
+	}()
+
 	return cm, func() {
 		close(done)
 		wg.Wait()
@@ -91,8 +100,11 @@ func analyzeIndex(
 	}
 
 	// load info
-	b := frac.BlockInfo{}
-	_ = b.Unpack(readBlock())
+	var b sealed.BlockInfo
+	if err := b.Unpack(readBlock()); err != nil {
+		logger.Fatal("error unpacking block info", zap.Error(err))
+	}
+
 	docsCount := int(b.Info.DocsTotal)
 
 	// load tokens

diff --git a/cmd/seq-db/seq-db.go b/cmd/seq-db/seq-db.go
@@ -22,6 +22,7 @@ import (
 	"github.com/ozontech/seq-db/config"
 	"github.com/ozontech/seq-db/consts"
 	"github.com/ozontech/seq-db/frac"
+	"github.com/ozontech/seq-db/frac/common"
 	"github.com/ozontech/seq-db/fracmanager"
 	"github.com/ozontech/seq-db/logger"
 	"github.com/ozontech/seq-db/mappingprovider"
@@ -250,11 +251,10 @@ func startStore(
 			CacheSize:         uint64(cfg.Resources.CacheSize),
 			SortCacheSize:     uint64(cfg.Resources.SortDocsCacheSize),
 			FracLoadLimit:     0,
-			ShouldReplay:      true,
 			MaintenanceDelay:  0,
 			CacheGCDelay:      0,
 			CacheCleanupDelay: 0,
-			SealParams: frac.SealParams{
+			SealParams: common.SealParams{
 				IDsZstdLevel:           cfg.Compression.SealedZstdCompressionLevel,
 				LIDsZstdLevel:          cfg.Compression.SealedZstdCompressionLevel,
 				TokenListZstdLevel:     cfg.Compression.SealedZstdCompressionLevel,

diff --git a/consts/consts.go b/consts/consts.go
@@ -11,10 +11,9 @@ const (
 	// DummyMID is used in aggregations when we do not need to build time series.
 	DummyMID = 0
 
-	IDsBlockSize     = int(4 * units.KiB)
-	RegularBlockSize = int(16 * units.KiB)
 	IDsPerBlock      = int(4 * units.KiB)
 	LIDBlockCap      = int(64 * units.KiB)
+	RegularBlockSize = int(16 * units.KiB)
 
 	DefaultMaintenanceDelay  = time.Second
 	DefaultCacheGCDelay      = 1 * time.Second
@@ -43,7 +42,7 @@ const (
 
 	MaxTextFieldValueLength = 32 * 1024
 
-	SealOnExitFracSizePercent = 20 // Percent of the max frac size, above which the fraction is sealed on exit
+	MinSealPercent = 20 // Percent of the max frac size, above which the fraction is sealed on exit
 
 	IngestorMaxInflightBulks = 32
 

diff --git a/frac/active.go b/frac/active.go
@@ -16,6 +16,8 @@ import (
 	"github.com/ozontech/seq-db/cache"
 	"github.com/ozontech/seq-db/config"
 	"github.com/ozontech/seq-db/consts"
+	"github.com/ozontech/seq-db/frac/common"
+	"github.com/ozontech/seq-db/frac/processor"
 	"github.com/ozontech/seq-db/logger"
 	"github.com/ozontech/seq-db/metric"
 	"github.com/ozontech/seq-db/metric/stopwatch"
@@ -33,12 +35,8 @@ type Active struct {
 
 	BaseFileName string
 
-	useMu    sync.RWMutex
-	suicided bool
-	released bool
-
 	infoMu sync.RWMutex
-	info   *Info
+	info   *common.Info
 
 	MIDs *UInt64s
 	RIDs *UInt64s
@@ -103,7 +101,7 @@ func NewActive(
 		writer:  NewActiveWriter(docsFile, metaFile, docsStats.Size(), metaStats.Size(), config.SkipFsync),
 
 		BaseFileName: baseFileName,
-		info:         NewInfo(baseFileName, uint64(docsStats.Size()), uint64(metaStats.Size())),
+		info:         common.NewInfo(baseFileName, uint64(docsStats.Size()), uint64(metaStats.Size())),
 		Config:       cfg,
 	}
 
@@ -265,23 +263,19 @@ func (f *Active) String() string {
 	return fracToString(f, "active")
 }
 
-func (f *Active) DataProvider(ctx context.Context) (DataProvider, func()) {
-	f.useMu.RLock()
-
-	if f.suicided || f.released || f.Info().DocsTotal == 0 { // it is empty active fraction state
-		if f.suicided {
-			metric.CountersTotal.WithLabelValues("fraction_suicided").Inc()
-		}
-		f.useMu.RUnlock()
-		return EmptyDataProvider{}, func() {}
+func (f *Active) Fetch(ctx context.Context, ids []seq.ID) ([][]byte, error) {
+	if f.Info().DocsTotal == 0 { // it is empty active fraction state
+		return nil, nil
 	}
+	return f.createDataProvider(ctx).Fetch(ids)
+}
 
-	// it is ordinary active fraction state
-	dp := f.createDataProvider(ctx)
-	return dp, func() {
-		dp.release()
-		f.useMu.RUnlock()
+func (f *Active) Search(ctx context.Context, params processor.SearchParams) (*seq.QPR, error) {
+	if f.Info().DocsTotal == 0 { // it is empty active fraction state
+		metric.CountersTotal.WithLabelValues("empty_data_provider").Inc()
+		return &seq.QPR{Aggs: make([]seq.AggregatableSamples, len(params.AggQ))}, nil
 	}
+	return f.createDataProvider(ctx).Search(params)
 }
 
 func (f *Active) createDataProvider(ctx context.Context) *activeDataProvider {
@@ -300,7 +294,7 @@ func (f *Active) createDataProvider(ctx context.Context) *activeDataProvider {
 	}
 }
 
-func (f *Active) Info() *Info {
+func (f *Active) Info() *common.Info {
 	f.infoMu.RLock()
 	defer f.infoMu.RUnlock()
 
@@ -317,10 +311,6 @@ func (f *Active) IsIntersecting(from, to seq.MID) bool {
 }
 
 func (f *Active) Release() {
-	f.useMu.Lock()
-	f.released = true
-	f.useMu.Unlock()
-
 	f.releaseMem()
 
 	if !f.Config.KeepMetaFile {
@@ -333,35 +323,6 @@ func (f *Active) Release() {
 	}
 }
 
-// Offload for [Active] fraction is no-op.
-//
-// Since search within [Active] fraction is too costly (we have to replay the whole index in memory),
-// we decided to support offloading only for [Sealed] fractions.
-func (f *Active) Offload(context.Context, storage.Uploader) (bool, error) {
-	return false, nil
-}
-
-func (f *Active) Suicide() {
-	f.useMu.Lock()
-	released := f.released
-	f.suicided = true
-	f.released = true
-	f.useMu.Unlock()
-
-	if released { // fraction can be suicided after release
-		if f.Config.KeepMetaFile {
-			f.removeMetaFile() // meta was not removed while release
-		}
-		if f.Config.SkipSortDocs {
-			f.removeDocsFiles() // docs was not removed while release
-		}
-	} else { // was not release
-		f.releaseMem()
-		f.removeMetaFile()
-		f.removeDocsFiles()
-	}
-}
-
 func (f *Active) releaseMem() {
 	f.writer.Stop()
 	f.TokenList.Stop()

diff --git a/frac/active_docs_positions.go b/frac/active_docs_positions.go
@@ -7,18 +7,22 @@ import (
 )
 
 type DocsPositions struct {
-	mu        sync.RWMutex
-	positions map[seq.ID]seq.DocPos
+	mu       sync.RWMutex
+	idToPos  map[seq.ID]seq.DocPos
+	lidToPos []seq.DocPos
 }
 
 func NewSyncDocsPositions() *DocsPositions {
-	return &DocsPositions{
-		positions: make(map[seq.ID]seq.DocPos),
+	dp := DocsPositions{
+		lidToPos: make([]seq.DocPos, 0),
+		idToPos:  make(map[seq.ID]seq.DocPos),
 	}
+	dp.lidToPos = append(dp.lidToPos, 0) // systemID
+	return &dp
 }
 
 func (dp *DocsPositions) Get(id seq.ID) seq.DocPos {
-	if val, ok := dp.positions[id]; ok {
+	if val, ok := dp.idToPos[id]; ok {
 		return val
 	}
 	return seq.DocPosNotFound
@@ -36,13 +40,22 @@ func (dp *DocsPositions) SetMultiple(ids []seq.ID, pos []seq.DocPos) []seq.ID {
 	dp.mu.Lock()
 	defer dp.mu.Unlock()
 
-	appended := make([]seq.ID, 0)
+	appended := make([]seq.ID, 0, len(ids))
 	for i, id := range ids {
-		// Positions may be equal in case of nested index.
-		if savedPos, ok := dp.positions[id]; !ok || savedPos == pos[i] {
-			dp.positions[id] = pos[i]
-			appended = append(appended, id)
+		p, ok := dp.idToPos[id]
+
+		if ok {
+			if p != pos[i] {
+				// same ID but different position
+				// this is a duplicate ID, we can't append it
+				continue
+			}
+		} else {
+			dp.idToPos[id] = pos[i]
 		}
+
+		dp.lidToPos = append(dp.lidToPos, pos[i])
+		appended = append(appended, id)
 	}
 	return appended
 }
diff --git a/frac/active_index.go b/frac/active_index.go
@@ -6,6 +6,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 
+	"github.com/ozontech/seq-db/frac/common"
 	"github.com/ozontech/seq-db/frac/processor"
 	"github.com/ozontech/seq-db/frac/sealed/lids"
 	"github.com/ozontech/seq-db/metric"
@@ -47,7 +48,7 @@ var (
 type activeDataProvider struct {
 	ctx    context.Context
 	config *Config
-	info   *Info
+	info   *common.Info
 
 	mids *UInt64s
 	rids *UInt64s