feat: make fsync configurable via fraction config

cmd/seq-db/seq-db.go

@@ -271,6 +271,7 @@ func startStore(
 				TokenTableZstdLevel:    cfg.Compression.SealedZstdCompressionLevel,
 				DocBlocksZstdLevel:     cfg.Compression.DocBlockZstdCompressionLevel,
 				DocBlockSize:           int(cfg.DocsSorting.DocBlockSize),
+				SkipFsync:              cfg.Resources.SkipFsync,
 			},
 			Fraction: frac.Config{
 				Search: frac.SearchConfig{
@@ -283,6 +284,7 @@ func startStore(
 				},
 				SkipSortDocs: !cfg.DocsSorting.Enabled,
 				KeepMetaFile: false,
+				SkipFsync:    cfg.Resources.SkipFsync,
 			},
 			OffloadingEnabled:    cfg.Offloading.Enabled,
 			OffloadingRetention:  cfg.Offloading.Retention,

frac/active.go

@@ -83,9 +83,9 @@ func NewActive(
 	cfg *Config,
 	skipMaskProvider skipMaskProvider,
 ) *Active {
-	docsFile, docsStats := mustOpenFile(baseFileName+consts.DocsFileSuffix, config.SkipFsync)
+	docsFile, docsStats := mustOpenFile(baseFileName+consts.DocsFileSuffix, cfg.SkipFsync)
 
-	metaFile, writer, metaReader, walReader, metaSize := mustOpenMetaWriter(baseFileName, readLimiter, docsFile, docsStats)
+	metaFile, writer, metaReader, walReader, metaSize := mustOpenMetaWriter(baseFileName, readLimiter, docsFile, docsStats, cfg.SkipFsync)
 
 	f := &Active{
 		TokenList:     NewActiveTokenList(config.IndexWorkers),
@@ -128,24 +128,25 @@ func mustOpenMetaWriter(
 	baseFileName string,
 	readLimiter *storage.ReadLimiter,
 	docsFile *os.File,
-	docsStats os.FileInfo) (*os.File, *ActiveWriter, *storage.DocBlocksReader, *storage.WalReader, uint64) {
+	docsStats os.FileInfo,
+	skipFsync bool) (*os.File, *ActiveWriter, *storage.DocBlocksReader, *storage.WalReader, uint64) {
 	legacyMetaFileName := baseFileName + consts.MetaFileSuffix
 
 	if _, err := os.Stat(legacyMetaFileName); err == nil {
 		// .meta file exists
-		metaFile, metaStats := mustOpenFile(legacyMetaFileName, config.SkipFsync)
+		metaFile, metaStats := mustOpenFile(legacyMetaFileName, skipFsync)
 		metaSize := uint64(metaStats.Size())
 		metaReader := storage.NewDocBlocksReader(readLimiter, metaFile)
-		writer := NewActiveWriterLegacy(docsFile, metaFile, docsStats.Size(), metaStats.Size(), config.SkipFsync)
+		writer := NewActiveWriterLegacy(docsFile, metaFile, docsStats.Size(), metaStats.Size(), skipFsync)
 		logger.Info("using legacy meta file format", zap.String("fraction", baseFileName))
 		return metaFile, writer, &metaReader, nil, metaSize
 	}
 
 	logger.Info("using new WAL format", zap.String("fraction", baseFileName))
 	walFileName := baseFileName + consts.WalFileSuffix
-	metaFile, metaStats := mustOpenFile(walFileName, config.SkipFsync)
+	metaFile, metaStats := mustOpenFile(walFileName, skipFsync)
 	metaSize := uint64(metaStats.Size())
-	writer := NewActiveWriter(docsFile, metaFile, docsStats.Size(), metaStats.Size(), config.SkipFsync)
+	writer := NewActiveWriter(docsFile, metaFile, docsStats.Size(), metaStats.Size(), skipFsync)
 	walReader, err := storage.NewWalReader(readLimiter, metaFile, baseFileName)
 	if err != nil {
 		logger.Fatal("failed to initialize WAL reader", zap.String("fraction", baseFileName), zap.Error(err))

frac/active_sealing_source.go

@@ -57,6 +57,7 @@ type ActiveSealingSource struct {
 	blocksOffsets []uint64              // Document block offsets
 	docsReader    *storage.DocsReader   // Document storage reader
 	lastErr       error                 // Last error
+	skipFsync     bool
 }
 
 // NewActiveSealingSource creates a new data source for sealing
@@ -87,6 +88,7 @@ func NewActiveSealingSource(active *Active, params common.SealParams) (*ActiveSe
 		docPosMap:     active.DocsPositions.idToPos,
 		blocksOffsets: active.DocBlocks.vals,
 		docsReader:    &active.sortReader,
+		skipFsync:     active.Config.SkipFsync,
 	}
 
 	src.prepareInfo()
@@ -371,18 +373,21 @@ func (src *ActiveSealingSource) SortDocs() error {
 	}
 	src.info.DocsOnDisk = uint64(stat.Size())
 
-	// Synchronize and rename file
-	if err := sdocsFile.Sync(); err != nil {
-		return err
+	if !src.skipFsync {
+		if err := sdocsFile.Sync(); err != nil {
+			return err
+		}
 	}
 	if err := sdocsFile.Close(); err != nil {
 		return err
 	}
 	if err := os.Rename(sdocsFile.Name(), src.info.Path+consts.SdocsFileSuffix); err != nil {
 		return err
 	}
-	if err := util.SyncPath(filepath.Dir(src.info.Path)); err != nil {
-		return err
+	if !src.skipFsync {
+		if err := util.SyncPath(filepath.Dir(src.info.Path)); err != nil {
+			return err
+		}
 	}
 
 	// Log compression statistics

frac/common/seal_params.go

@@ -9,4 +9,6 @@ type SealParams struct {
 
 	DocBlocksZstdLevel int // DocBlocksZstdLevel is the zstd compress level of each document block.
 	DocBlockSize       int // DocBlockSize is decompressed payload size of document block.
+
+	SkipFsync bool
 }

frac/config.go

@@ -5,6 +5,7 @@ type Config struct {
 
 	SkipSortDocs bool
 	KeepMetaFile bool
+	SkipFsync    bool
 }
 
 type SearchConfig struct {

frac/sealed/sealing/sealer.go

@@ -59,9 +59,11 @@ func Seal(src Source, params common.SealParams) (*sealed.PreloadedData, error) {
 		return nil, err
 	}
 
-	// Ensure data is flushed to disk
-	if err := indexFile.Sync(); err != nil {
-		return nil, err
+	if !params.SkipFsync {
+		// Ensure data is flushed to disk
+		if err := indexFile.Sync(); err != nil {
+			return nil, err
+		}
 	}
 
 	// Get final file size for metadata
@@ -81,8 +83,10 @@ func Seal(src Source, params common.SealParams) (*sealed.PreloadedData, error) {
 		return nil, err
 	}
 
-	// Ensure directory metadata is synced to disk
-	util.MustSyncPath(filepath.Dir(info.Path))
+	if !params.SkipFsync {
+		// Ensure directory metadata is synced to disk
+		util.MustSyncPath(filepath.Dir(info.Path))
+	}
 
 	// Build preloaded data structure for fast query access
 	lidsTable := indexSealer.LIDsTable()