Count each file, byte and upload once in backup statistics (closes #225)

The scanner added a changed file's bytes again for each new chunk and
counted a file as unchanged for each chunk already stored. It now
counts files and bytes once, in the scan phase, and counts its own
uploads, so a --cron run, which has no progress reporter, records
them. The blob count no longer adds earlier paths' blobs again.

The snapshots row now stores the size of all files in total_size and
the referenced blobs' sizes in blob_size, blob_uncompressed_size and
compression_ratio, as docs/DATAMODEL.md says. Those sizes come from
one query, and a failed query fails the snapshot. DATAMODEL.md now
says chunk_count and blob_count count what the run added.

Removed UpdateSnapshotStats and GetCountBySnapshot, which nothing
calls any more.

Model: opus-5-5

ARCHITECTURE.md

@@ -335,10 +335,10 @@ CreateSnapshot(opts)
     │       │
     │       └─► Accumulate statistics
     │
-    ├─► SnapshotManager.UpdateSnapshotStatsExtended()
-    │
     ├─► SnapshotManager.PopulateSnapshotBlobs()   // record referenced blobs
     │
+    ├─► SnapshotManager.UpdateSnapshotStatsExtended()
+    │
     ├─► SnapshotManager.ExportSnapshotMetadata()
     │       │
     │       ├─► Copy database to temp file

TODO.md

@@ -22,6 +22,19 @@ the tag exists and is exercised; what is left is merging `next` to
 
 # Completed Steps
 
+- 2026-10-06: Made the backup summary and the `snapshots` row count each
+  file, byte and upload once
+  ([issue #225](https://git.eeqj.de/sneak/vaultik/issues/225)). The
+  scanner added a file's bytes again for each new chunk and counted a
+  file as unchanged for each chunk already stored, so a first backup
+  reported twice its size and "backed up" could go negative. Upload
+  figures came from the progress reporter, which `--cron` turns off, and
+  `blob_count` counted earlier paths' blobs again for each later path.
+  The scanner now counts uploads itself; `blob_size`,
+  `blob_uncompressed_size` and `compression_ratio` describe the blobs
+  the snapshot references, and `docs/DATAMODEL.md` now says
+  `chunk_count` and `blob_count` count what the run added.
+
 - 2026-10-06: Made command output follow the README's stdout and stderr
   rules ([issue #224](https://git.eeqj.de/sneak/vaultik/issues/224)). The
   startup banner went to stdout, so a `completion` script or a

docs/DATAMODEL.md

@@ -117,10 +117,10 @@ Tracks backup snapshots.
 - `started_at` (INTEGER) - Start timestamp
 - `completed_at` (INTEGER) - Completion timestamp (NULL if in progress)
 - `file_count` (INTEGER) - Number of files in snapshot
-- `chunk_count` (INTEGER) - Number of unique chunks
-- `blob_count` (INTEGER) - Number of blobs referenced
+- `chunk_count` (INTEGER) - Number of chunks this snapshot stored that were not stored before
+- `blob_count` (INTEGER) - Number of blobs this snapshot created
 - `total_size` (INTEGER) - Total size of all files
-- `blob_size` (INTEGER) - Total size of all blobs (compressed)
+- `blob_size` (INTEGER) - Total compressed size of all referenced blobs
 - `blob_uncompressed_size` (INTEGER) - Total uncompressed size of all referenced blobs
 - `compression_ratio` (REAL) - Compression ratio achieved
 - `compression_level` (INTEGER) - Compression level used for this snapshot

internal/database/models.go

@@ -99,8 +99,8 @@ type Snapshot struct {
 	StartedAt          time.Time
 	CompletedAt        *time.Time // nil if still in progress
 	FileCount          int64
-	ChunkCount         int64
-	BlobCount          int64
+	ChunkCount         int64 // Chunks this snapshot stored that were not stored before
+	BlobCount          int64 // Blobs this snapshot created
 	TotalSize          int64 // Total size of all referenced files
 
 	// BlobSize is the total size of all referenced blobs (compressed and

internal/database/snapshots.go

@@ -127,6 +127,7 @@ func (r *SnapshotRepository) UpdateExtendedStats(
 	snapshotID string,
 	blobUncompressedSize int64,
 	compressionLevel int,
+	uploadBytes int64,
 	uploadDurationMs int64,
 ) error {
 	compressionRatio, err := r.extendedCompressionRatio(
@@ -141,7 +142,7 @@ func (r *SnapshotRepository) UpdateExtendedStats(
 		SET blob_uncompressed_size = ?,
 		    compression_ratio = ?,
 		    compression_level = ?,
-		    upload_bytes = blob_size,
+		    upload_bytes = ?,
 		    upload_duration_ms = ?
 		WHERE id = ?
 	`
@@ -149,11 +150,11 @@ func (r *SnapshotRepository) UpdateExtendedStats(
 	if tx != nil {
 		_, err = tx.ExecContext(ctx, query,
 			blobUncompressedSize, compressionRatio, compressionLevel,
-			uploadDurationMs, snapshotID)
+			uploadBytes, uploadDurationMs, snapshotID)
 	} else {
 		_, err = r.db.ExecWithLog(ctx, query,
 			blobUncompressedSize, compressionRatio, compressionLevel,
-			uploadDurationMs, snapshotID)
+			uploadBytes, uploadDurationMs, snapshotID)
 	}
 
 	if err != nil {
@@ -543,6 +544,30 @@ func (r *SnapshotRepository) GetSnapshotTotalCompressedSize(
 	return totalSize, nil
 }
 
+// GetSnapshotBlobSizes returns the total compressed and uncompressed sizes
+// of all blobs referenced by a snapshot.
+func (r *SnapshotRepository) GetSnapshotBlobSizes(
+	ctx context.Context, snapshotID string,
+) (int64, int64, error) {
+	query := `
+		SELECT COALESCE(SUM(b.compressed_size), 0),
+			COALESCE(SUM(b.uncompressed_size), 0)
+		FROM snapshot_blobs sb
+		JOIN blobs b ON sb.blob_hash = b.blob_hash
+		WHERE sb.snapshot_id = ?
+	`
+
+	var compressed, uncompressed int64
+
+	err := r.db.conn.QueryRowContext(ctx, query, snapshotID).Scan(
+		&compressed, &uncompressed)
+	if err != nil {
+		return 0, 0, fmt.Errorf("querying snapshot blob sizes: %w", err)
+	}
+
+	return compressed, uncompressed, nil
+}
+
 // GetSnapshotUncompressedChunkSize returns the sum of plaintext sizes of all unique
 // chunks referenced by a snapshot (via snapshot_files → file_chunks → chunks).
 func (r *SnapshotRepository) GetSnapshotUncompressedChunkSize(

internal/database/snapshots_test.go

@@ -145,6 +145,65 @@ func TestSnapshotRepositoryUpdateCounts(t *testing.T) {
 	}
 }
 
+// GetSnapshotBlobSizes totals the blobs the snapshot references, and only
+// those.
+func TestSnapshotRepositoryGetSnapshotBlobSizes(t *testing.T) {
+	t.Parallel()
+
+	db, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	ctx := context.Background()
+	repos := database.NewRepositories(db)
+
+	snapshot := &database.Snapshot{
+		ID:             "2024-01-03T12:00:00Z",
+		Hostname:       testHostname,
+		VaultikVersion: testVersion,
+		StartedAt:      time.Now().Truncate(time.Second),
+	}
+
+	err := repos.Snapshots.Create(ctx, nil, snapshot)
+	if err != nil {
+		t.Fatalf("failed to create snapshot: %v", err)
+	}
+
+	blobs := []*database.Blob{
+		{Hash: "referenced-1", CompressedSize: 10, UncompressedSize: 100},
+		{Hash: "referenced-2", CompressedSize: 20, UncompressedSize: 200},
+		{Hash: "unreferenced", CompressedSize: 40, UncompressedSize: 400},
+	}
+
+	for _, blob := range blobs {
+		blob.ID = types.NewBlobID()
+		blob.CreatedTS = time.Now().Truncate(time.Second)
+
+		err = repos.Blobs.Create(ctx, nil, blob)
+		if err != nil {
+			t.Fatalf("failed to create blob %s: %v", blob.Hash, err)
+		}
+	}
+
+	for _, blob := range blobs[:2] {
+		err = repos.Snapshots.AddBlob(ctx, nil, snapshot.ID.String(),
+			blob.ID, blob.Hash)
+		if err != nil {
+			t.Fatalf("failed to add blob %s to snapshot: %v", blob.Hash, err)
+		}
+	}
+
+	compressed, uncompressed, err := repos.Snapshots.GetSnapshotBlobSizes(
+		ctx, snapshot.ID.String())
+	if err != nil {
+		t.Fatalf("failed to get snapshot blob sizes: %v", err)
+	}
+
+	if compressed != 30 || uncompressed != 300 {
+		t.Errorf("blob sizes: got %d and %d, want 30 and 300",
+			compressed, uncompressed)
+	}
+}
+
 func TestSnapshotRepositoryListRecent(t *testing.T) {
 	t.Parallel()
 

internal/database/uploads.go

@@ -158,19 +158,3 @@ type UploadStats struct {
 	MinDurationMs int64
 	MaxDurationMs int64
 }
-
-// GetCountBySnapshot returns the count of uploads for a specific snapshot
-func (r *UploadRepository) GetCountBySnapshot(
-	ctx context.Context, snapshotID string,
-) (int64, error) {
-	query := `SELECT COUNT(*) FROM uploads WHERE snapshot_id = ?`
-
-	var count int64
-
-	err := r.conn.QueryRowContext(ctx, query, snapshotID).Scan(&count)
-	if err != nil {
-		return 0, err
-	}
-
-	return count, nil
-}

internal/snapshot/progress.go

@@ -66,7 +66,6 @@ type ProgressStats struct {
 	BlobsCreated     atomic.Int64
 	BlobsUploaded    atomic.Int64
 	BytesUploaded    atomic.Int64
-	UploadDurationMs atomic.Int64 // Total milliseconds spent uploading
 	CurrentFile      atomic.Value // stores string
 	TotalSize        atomic.Int64 // Total size to process (set after scan phase)
 	TotalFiles       atomic.Int64 // Total files to process in phase 2
@@ -231,9 +230,6 @@ func (pr *ProgressReporter) ReportUploadComplete(
 	// Clear current upload
 	pr.stats.CurrentUpload.Store((*UploadInfo)(nil))
 
-	// Add to total upload duration
-	pr.stats.UploadDurationMs.Add(duration.Milliseconds())
-
 	// Calculate speed
 	if duration < time.Millisecond {
 		duration = time.Millisecond

internal/snapshot/scanner.go

@@ -92,9 +92,6 @@ type Scanner struct {
 
 	// Mutex for coordinating blob creation
 	packerMu sync.Mutex // Blocks chunk production during blob creation
-
-	// Context for cancellation
-	scanCtx context.Context //nolint:containedctx // set per-Scan for packer callbacks
 }
 
 // Periodic status output intervals and thresholds for the scan and
@@ -134,7 +131,9 @@ type ScannerConfig struct {
 	SkipErrors bool
 }
 
-// ScanResult contains the results of a scan operation
+// ScanResult contains the results of a scan operation. Files and bytes
+// are counted per file: BytesScanned is the size of the new and changed
+// files, BytesSkipped that of the unchanged ones.
 type ScanResult struct {
 	FilesScanned   int
 	FilesSkipped   int
@@ -144,6 +143,9 @@ type ScanResult struct {
 	BytesDeleted   int64
 	ChunksCreated  int
 	BlobsCreated   int
+	BlobsUploaded  int
+	BytesUploaded  int64
+	UploadDuration time.Duration
 	StartTime      time.Time
 	EndTime        time.Time
 }
@@ -211,7 +213,6 @@ func (s *Scanner) Scan(
 	s.snapshotID = snapshotID
 	// Store source path for file records (used during restore)
 	s.currentSourcePath = path
-	s.scanCtx = ctx
 	result := &ScanResult{
 		StartTime: time.Now().UTC(),
 	}
@@ -219,7 +220,9 @@ func (s *Scanner) Scan(
 	// Set blob handler for concurrent upload
 	if s.storage != nil {
 		log.Debug("Setting blob handler for storage uploads")
-		s.packer.SetBlobHandler(s.handleBlobReady)
+		s.packer.SetBlobHandler(func(blobWithReader *blob.WithReader) error {
+			return s.handleBlobReady(ctx, blobWithReader, result)
+		})
 	} else {
 		log.Debug("No storage configured, blobs will not be uploaded")
 	}
@@ -288,8 +291,7 @@ func (s *Scanner) Scan(
 		log.Info("Phase 2/3: Skipping (no files need processing, metadata-only snapshot)")
 	}
 
-	// Finalize result with blob statistics
-	s.finalizeScanResult(ctx, result)
+	result.EndTime = time.Now().UTC()
 
 	return result, nil
 }
@@ -431,27 +433,6 @@ func (s *Scanner) summarizeScanPhase(
 	s.ui.Completef("%s.", msg)
 }
 
-// finalizeScanResult populates final blob statistics in the scan result
-// by querying the packer and database for blob/upload counts
-func (s *Scanner) finalizeScanResult(ctx context.Context, result *ScanResult) {
-	blobs := s.packer.GetFinishedBlobs()
-	result.BlobsCreated += len(blobs)
-
-	// Query database for actual blob count created during this snapshot
-	// The database is authoritative, especially for concurrent blob uploads
-	// We count uploads rather than all snapshot_blobs to get only NEW blobs
-	if s.snapshotID != "" {
-		uploadCount, err := s.repos.Uploads.GetCountBySnapshot(ctx, s.snapshotID)
-		if err != nil {
-			log.Warn("Failed to query upload count from database", "error", err)
-		} else {
-			result.BlobsCreated = int(uploadCount)
-		}
-	}
-
-	result.EndTime = time.Now().UTC()
-}
-
 // loadKnownFiles loads the known files at and beneath path from the
 // database into a map for fast lookup. Every loaded file the scan does
 // not find is counted as deleted. This avoids per-file database queries
@@ -1511,24 +1492,24 @@ func (s *Scanner) finalizeProcessPhase(ctx context.Context, result *ScanResult)
 }
 
 // handleBlobReady is called by the packer when a blob is finalized
-func (s *Scanner) handleBlobReady(blobWithReader *blob.WithReader) error {
+func (s *Scanner) handleBlobReady(
+	ctx context.Context, blobWithReader *blob.WithReader, result *ScanResult,
+) error {
 	startTime := time.Now().UTC()
 	finishedBlob := blobWithReader.FinishedBlob
 
+	result.BlobsCreated++
+
 	if s.progress != nil {
 		s.progress.ReportUploadStart(finishedBlob.Hash, finishedBlob.Compressed)
 		s.progress.GetStats().BlobsCreated.Add(1)
 	}
 
-	ctx := s.scanCtx
-	if ctx == nil {
-		ctx = context.Background()
-	}
-
 	blobPath := fmt.Sprintf("blobs/%s/%s/%s",
 		finishedBlob.Hash[:2], finishedBlob.Hash[2:4], finishedBlob.Hash)
 
-	blobExists, err := s.uploadBlobIfNeeded(ctx, blobPath, blobWithReader, startTime)
+	blobExists, err := s.uploadBlobIfNeeded(
+		ctx, blobPath, blobWithReader, startTime, result)
 	if err != nil {
 		s.cleanupBlobTempFile(blobWithReader)
 
@@ -1563,6 +1544,7 @@ func (s *Scanner) uploadBlobIfNeeded(
 	blobPath string,
 	blobWithReader *blob.WithReader,
 	startTime time.Time,
+	result *ScanResult,
 ) (bool, error) {
 	finishedBlob := blobWithReader.FinishedBlob
 
@@ -1598,6 +1580,10 @@ func (s *Scanner) uploadBlobIfNeeded(
 	uploadDuration := time.Since(startTime)
 	uploadSpeedBps := float64(finishedBlob.Compressed) / uploadDuration.Seconds()
 
+	result.BlobsUploaded++
+	result.BytesUploaded += finishedBlob.Compressed
+	result.UploadDuration += uploadDuration
+
 	s.ui.Completef("Uploaded blob %s (%s) in %s at %s.",
 		s.ui.Hex(finishedBlob.Hash),
 		s.ui.Size(finishedBlob.Compressed),
@@ -1813,9 +1799,9 @@ func (s *Scanner) processFileStreaming(
 			size:   chunk.Size,
 		})
 
-		s.updateChunkStats(chunkExists, chunk.Size, result)
-
 		if !chunkExists {
+			s.updateChunkStats(chunk.Size, result)
+
 			err := s.addChunkToPacker(ctx, chunk)
 			if err != nil {
 				// Mark as a packer error so --skip-errors cannot swallow it:
@@ -1843,20 +1829,11 @@ func (s *Scanner) processFileStreaming(
 	return nil
 }
 
-// updateChunkStats updates scan result and progress stats for a processed chunk
-func (s *Scanner) updateChunkStats(
-	chunkExists bool, chunkSize int64, result *ScanResult,
-) {
-	if chunkExists {
-		result.FilesSkipped++
-
-		result.BytesSkipped += chunkSize
-		if s.progress != nil {
-			s.progress.GetStats().BytesSkipped.Add(chunkSize)
-		}
-	} else {
+// updateChunkStats counts a chunk that was not already stored. The scan
+// result's file counts, BytesScanned and BytesSkipped are not touched
+// here: the scan phase counts each file once.
+func (s *Scanner) updateChunkStats(chunkSize int64, result *ScanResult) {
 	result.ChunksCreated++
-		result.BytesScanned += chunkSize
 
 	if s.progress != nil {
 		s.progress.GetStats().ChunksCreated.Add(1)
@@ -1864,7 +1841,6 @@ func (s *Scanner) updateChunkStats(
 		s.progress.UpdateChunkingActivity()
 	}
 }
-}
 
 // addChunkToPacker adds a chunk to the blob packer, finalizing the current
 // blob if needed

internal/snapshot/snapshot.go

@@ -154,26 +154,6 @@ func (sm *SnapshotManager) CreateSnapshotWithName(
 	return snapshotID, nil
 }
 
-// UpdateSnapshotStats updates the statistics for a snapshot during backup
-func (sm *SnapshotManager) UpdateSnapshotStats(
-	ctx context.Context, snapshotID string, stats BackupStats,
-) error {
-	err := sm.repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
-		return sm.repos.Snapshots.UpdateCounts(ctx, tx, snapshotID,
-			int64(stats.FilesScanned),
-			int64(stats.ChunksCreated),
-			int64(stats.BlobsCreated),
-			stats.BytesScanned,
-			stats.BytesUploaded,
-		)
-	})
-	if err != nil {
-		return fmt.Errorf("updating snapshot stats: %w", err)
-	}
-
-	return nil
-}
-
 // UpdateSnapshotStatsExtended updates snapshot statistics with extended metrics.
 // This includes compression level, uncompressed blob size, and upload duration.
 func (sm *SnapshotManager) UpdateSnapshotStatsExtended(
@@ -185,8 +165,8 @@ func (sm *SnapshotManager) UpdateSnapshotStatsExtended(
 			int64(stats.FilesScanned),
 			int64(stats.ChunksCreated),
 			int64(stats.BlobsCreated),
-			stats.BytesScanned,
-			stats.BytesUploaded,
+			stats.TotalSize,
+			stats.BlobSize,
 		)
 		if err != nil {
 			return err
@@ -196,6 +176,7 @@ func (sm *SnapshotManager) UpdateSnapshotStatsExtended(
 		return sm.repos.Snapshots.UpdateExtendedStats(ctx, tx, snapshotID,
 			stats.BlobUncompressedSize,
 			stats.CompressionLevel,
+			stats.BytesUploaded,
 			stats.UploadDurationMs,
 		)
 	})
@@ -890,7 +871,7 @@ func (sm *SnapshotManager) getFileSize(path string) int64 {
 // BackupStats contains statistics from a backup operation
 type BackupStats struct {
 	FilesScanned  int
-	BytesScanned  int64
+	TotalSize     int64 // Total size of all files examined
 	ChunksCreated int
 	BlobsCreated  int
 	BytesUploaded int64
@@ -900,6 +881,7 @@ type BackupStats struct {
 type ExtendedBackupStats struct {
 	BackupStats
 
+	BlobSize             int64 // Total compressed size of all referenced blobs
 	BlobUncompressedSize int64 // Total uncompressed size of all referenced blobs
 	CompressionLevel     int   // Compression level used for this snapshot
 	UploadDurationMs     int64 // Total milliseconds spent uploading to S3

internal/vaultik/snapshot.go

@@ -189,6 +189,11 @@ type snapshotStats struct {
 	totalBytesUploaded int64
 	totalBlobsUploaded int
 	uploadDuration     time.Duration
+
+	// The sizes of all blobs the snapshot references, set by
+	// finalizeSnapshotMetadata once snapshot_blobs is populated.
+	blobSize             int64
+	blobUncompressedSize int64
 }
 
 // createNamedSnapshot creates a single named snapshot
@@ -228,8 +233,6 @@ func (v *Vaultik) createNamedSnapshot(
 		return err
 	}
 
-	v.collectUploadStats(scanner, stats)
-
 	err = v.finalizeSnapshotMetadata(snapshotID, stats)
 	if err != nil {
 		return err
@@ -314,6 +317,9 @@ func (v *Vaultik) scanAllDirectories(
 		stats.totalBytesSkipped += result.BytesSkipped
 		stats.totalFilesDeleted += result.FilesDeleted
 		stats.totalBytesDeleted += result.BytesDeleted
+		stats.totalBlobsUploaded += result.BlobsUploaded
+		stats.totalBytesUploaded += result.BytesUploaded
+		stats.uploadDuration += result.UploadDuration
 
 		log.Info("Directory scan complete",
 			"path", dir,
@@ -329,18 +335,6 @@ func (v *Vaultik) scanAllDirectories(
 	return stats, nil
 }
 
-// collectUploadStats gathers upload statistics from the scanner's
-// progress reporter.
-func (v *Vaultik) collectUploadStats(scanner *snapshot.Scanner, stats *snapshotStats) {
-	if s := scanner.GetProgress(); s != nil {
-		progressStats := s.GetStats()
-		stats.totalBytesUploaded = progressStats.BytesUploaded.Load()
-		stats.totalBlobsUploaded = int(progressStats.BlobsUploaded.Load())
-		stats.uploadDuration = time.Duration(
-			progressStats.UploadDurationMs.Load()) * time.Millisecond
-	}
-}
-
 // finalizeSnapshotMetadata updates stats, exports metadata, and only then
 // marks the snapshot complete. Recording completion last is deliberate: an
 // export interrupted by a crash leaves the snapshot incomplete rather than
@@ -350,31 +344,39 @@ func (v *Vaultik) collectUploadStats(scanner *snapshot.Scanner, stats *snapshotS
 func (v *Vaultik) finalizeSnapshotMetadata(
 	snapshotID string, stats *snapshotStats,
 ) error {
+	// snapshot_blobs must be populated before the blob sizes below, which
+	// total the snapshot's blobs, and before the export, which builds the
+	// manifest and the trimmed metadata database from it.
+	err := v.SnapshotManager.PopulateSnapshotBlobs(v.ctx, snapshotID)
+	if err != nil {
+		return fmt.Errorf("populating snapshot blobs: %w", err)
+	}
+
+	stats.blobSize, stats.blobUncompressedSize, err =
+		v.Repositories.Snapshots.GetSnapshotBlobSizes(v.ctx, snapshotID)
+	if err != nil {
+		return fmt.Errorf("getting snapshot blob sizes: %w", err)
+	}
+
 	extStats := snapshot.ExtendedBackupStats{
 		BackupStats: snapshot.BackupStats{
 			FilesScanned:  stats.totalFiles,
-			BytesScanned:  stats.totalBytes,
+			TotalSize:     stats.totalBytes + stats.totalBytesSkipped,
 			ChunksCreated: stats.totalChunks,
 			BlobsCreated:  stats.totalBlobs,
 			BytesUploaded: stats.totalBytesUploaded,
 		},
-		BlobUncompressedSize: 0,
+		BlobSize:             stats.blobSize,
+		BlobUncompressedSize: stats.blobUncompressedSize,
 		CompressionLevel:     v.Config.CompressionLevel,
 		UploadDurationMs:     stats.uploadDuration.Milliseconds(),
 	}
 
-	err := v.SnapshotManager.UpdateSnapshotStatsExtended(v.ctx, snapshotID, extStats)
+	err = v.SnapshotManager.UpdateSnapshotStatsExtended(v.ctx, snapshotID, extStats)
 	if err != nil {
 		return fmt.Errorf("updating snapshot stats: %w", err)
 	}
 
-	// snapshot_blobs must be populated before the export, which builds the
-	// manifest and the trimmed metadata database from it.
-	err = v.SnapshotManager.PopulateSnapshotBlobs(v.ctx, snapshotID)
-	if err != nil {
-		return fmt.Errorf("populating snapshot blobs: %w", err)
-	}
-
 	err = v.SnapshotManager.ExportSnapshotMetadata(
 		v.ctx, v.Config.IndexPath, snapshotID)
 	if err != nil {
@@ -409,12 +411,10 @@ func (v *Vaultik) printSnapshotSummary(
 	totalFilesChanged := stats.totalFiles - stats.totalFilesSkipped
 	totalBytesAll := stats.totalBytes + stats.totalBytesSkipped
 
-	// Get total blob sizes from database
-	compressedSize, uncompressedSize := v.getSnapshotBlobSizes(snapshotID)
-
 	var compressionRatio float64
-	if uncompressedSize > 0 {
-		compressionRatio = float64(compressedSize) / float64(uncompressedSize)
+	if stats.blobUncompressedSize > 0 {
+		compressionRatio = float64(stats.blobSize) /
+			float64(stats.blobUncompressedSize)
 	} else {
 		compressionRatio = 1.0
 	}
@@ -442,8 +442,8 @@ func (v *Vaultik) printSnapshotSummary(
 
 	if stats.totalBlobsUploaded > 0 {
 		v.UI.Detailf("Storage: %s compressed from %s (%.2fx ratio).",
-			v.UI.Size(compressedSize),
-			v.UI.Size(uncompressedSize),
+			v.UI.Size(stats.blobSize),
+			v.UI.Size(stats.blobUncompressedSize),
 			compressionRatio)
 		v.UI.Detailf("Upload: %d blobs, %s in %s (%s).",
 			stats.totalBlobsUploaded,
@@ -455,27 +455,6 @@ func (v *Vaultik) printSnapshotSummary(
 	v.UI.Detailf("Snapshot create duration: %s.", v.UI.Duration(snapshotDuration))
 }
 
-// getSnapshotBlobSizes returns total compressed and uncompressed blob
-// sizes for a snapshot.
-func (v *Vaultik) getSnapshotBlobSizes(snapshotID string) (int64, int64) {
-	var compressed, uncompressed int64
-
-	blobHashes, err := v.Repositories.Snapshots.GetBlobHashes(v.ctx, snapshotID)
-	if err != nil {
-		return 0, 0
-	}
-
-	for _, hash := range blobHashes {
-		blob, err := v.Repositories.Blobs.GetByHash(v.ctx, hash)
-		if err == nil && blob != nil {
-			compressed += blob.CompressedSize
-			uncompressed += blob.UncompressedSize
-		}
-	}
-
-	return compressed, uncompressed
-}
-
 // SnapshotPurgeOptions contains options for the snapshot purge command.
 type SnapshotPurgeOptions struct {
 	KeepLatest bool // Keep only the most recent snapshot per name

internal/vaultik/snapshot_summary_test.go

@@ -0,0 +1,285 @@
+package vaultik_test
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/config"
+	"sneak.berlin/go/vaultik/internal/database"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/storage"
+	"sneak.berlin/go/vaultik/internal/storage/faultstore"
+	"sneak.berlin/go/vaultik/internal/ui"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// These tests cover https://git.eeqj.de/sneak/vaultik/issues/225: the
+// summary printed after a backup, and the statistics stored in the
+// snapshots table, count each file, byte and upload once, and a --cron
+// run records its uploads.
+
+// summaryUploadDelay slows every blob upload, so a run's upload time is
+// at least this long per blob even on a local store.
+const summaryUploadDelay = 20 * time.Millisecond
+
+// summaryEnv is a backup setup whose user-facing output is kept in out.
+type summaryEnv struct {
+	v     *vaultik.Vaultik
+	db    *database.DB
+	repos *database.Repositories
+	out   *bytes.Buffer
+
+	// aPath is a.bin, whose content copy.bin repeats; aSize is its size
+	// and totalSize the size of all three source files.
+	aPath     string
+	aSize     int64
+	totalSize int64
+}
+
+// newSummaryEnv writes src/one/a.bin, src/one/small.txt and
+// src/two/copy.bin, a copy of a.bin. Every chunk of copy.bin is therefore
+// already stored by the time the backup reaches it.
+//
+// The snapshot names "first" and "second" back up src; "split" backs up
+// src/one and src/two as two paths.
+func newSummaryEnv(t *testing.T) *summaryEnv {
+	t.Helper()
+
+	log.Initialize(log.Config{})
+
+	fs := afero.NewOsFs()
+	tempDir := t.TempDir()
+	srcDir := filepath.Join(tempDir, "src")
+	dirOne := filepath.Join(srcDir, "one")
+	dirTwo := filepath.Join(srcDir, "two")
+	dbPath := filepath.Join(tempDir, "index.sqlite")
+	ctx := context.Background()
+
+	aContent := bytesPattern("a-", int(3*faultChunkSize))
+	smallContent := []byte("hello vaultik")
+	files := map[string][]byte{
+		filepath.Join(dirOne, "a.bin"):     aContent,
+		filepath.Join(dirOne, "small.txt"): smallContent,
+		filepath.Join(dirTwo, "copy.bin"):  aContent,
+	}
+
+	for path, content := range files {
+		require.NoError(t, fs.MkdirAll(filepath.Dir(path), 0o755))
+		require.NoError(t, afero.WriteFile(fs, path, content, 0o644))
+	}
+
+	cfg := faultTestConfig()
+	cfg.IndexPath = dbPath
+	cfg.ChunkSize = config.Size(faultChunkSize)
+	cfg.Snapshots = map[string]config.SnapshotConfig{
+		"first":  {Paths: []string{srcDir}},
+		"second": {Paths: []string{srcDir}},
+		"split":  {Paths: []string{dirOne, dirTwo}},
+	}
+
+	inner, err := storage.NewFileStorer(filepath.Join(tempDir, "remote"))
+	require.NoError(t, err)
+
+	store := faultstore.New(inner)
+	store.OnPut = func(key string) faultstore.PutAction {
+		if strings.HasPrefix(key, "blobs/") {
+			time.Sleep(summaryUploadDelay)
+		}
+
+		return faultstore.PutNormal
+	}
+
+	db, err := database.New(ctx, dbPath)
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = db.Close() })
+
+	repos := database.NewRepositories(db)
+	out := &bytes.Buffer{}
+	v := newBackupVaultik(ctx, cfg, store, repos, db, fs)
+	v.UI = ui.NewWithColor(out, false)
+
+	return &summaryEnv{
+		v:         v,
+		db:        db,
+		repos:     repos,
+		out:       out,
+		aPath:     filepath.Join(dirOne, "a.bin"),
+		aSize:     int64(len(aContent)),
+		totalSize: int64(2*len(aContent) + len(smallContent)),
+	}
+}
+
+// backUp runs a backup of the named snapshot and returns its output.
+func (e *summaryEnv) backUp(t *testing.T, name string, cron bool) string {
+	t.Helper()
+
+	e.out.Reset()
+	require.NoError(t, e.v.CreateSnapshot(&vaultik.SnapshotCreateOptions{
+		Cron:      cron,
+		Snapshots: []string{name},
+	}))
+
+	return e.out.String()
+}
+
+// snapshot returns the local snapshots row of the snapshot named name.
+func (e *summaryEnv) snapshot(t *testing.T, name string) *database.Snapshot {
+	t.Helper()
+
+	ctx := context.Background()
+	snap, err := e.repos.Snapshots.GetByID(ctx,
+		localSnapshotID(ctx, t, e.repos, name))
+	require.NoError(t, err)
+	require.NotNil(t, snap)
+
+	return snap
+}
+
+// uploads returns how many blobs the snapshot uploaded and their
+// total size, as recorded in the uploads table.
+func (e *summaryEnv) uploads(t *testing.T, snapshotID string) (int64, int64) {
+	t.Helper()
+
+	var count, size int64
+
+	err := e.db.Conn().QueryRowContext(context.Background(), `
+		SELECT COUNT(*), COALESCE(SUM(size), 0)
+		FROM uploads WHERE snapshot_id = ?`, snapshotID).Scan(&count, &size)
+	require.NoError(t, err)
+
+	return count, size
+}
+
+// referencedBlobSizes returns the compressed and uncompressed sizes of
+// all blobs the snapshot references.
+func (e *summaryEnv) referencedBlobSizes(
+	t *testing.T, snapshotID string,
+) (int64, int64) {
+	t.Helper()
+
+	var compressed, uncompressed int64
+
+	err := e.db.Conn().QueryRowContext(context.Background(), `
+		SELECT COALESCE(SUM(b.compressed_size), 0),
+			COALESCE(SUM(b.uncompressed_size), 0)
+		FROM snapshot_blobs sb JOIN blobs b ON b.blob_hash = sb.blob_hash
+		WHERE sb.snapshot_id = ?`, snapshotID).Scan(&compressed, &uncompressed)
+	require.NoError(t, err)
+
+	return compressed, uncompressed
+}
+
+// filesLine returns the summary's line of file counts.
+func filesLine(examined, backedUp, unchanged int) string {
+	return fmt.Sprintf("Files: %d examined, %d backed up, %d unchanged.",
+		examined, backedUp, unchanged)
+}
+
+// dataLine returns the summary's line of byte counts.
+func (e *summaryEnv) dataLine(total, backedUp int64) string {
+	return fmt.Sprintf("Data: %s total (%s backed up).",
+		e.v.UI.Size(total), e.v.UI.Size(backedUp))
+}
+
+// A first backup stores copy.bin's chunks while backing up a.bin, so
+// copy.bin's chunks are deduplicated within the run. Each file and byte
+// is still counted once.
+//
+//nolint:paralleltest // installs the global logger via log.Initialize
+func TestSnapshotSummaryFirstRun(t *testing.T) {
+	env := newSummaryEnv(t)
+
+	summary := env.backUp(t, "first", false)
+
+	assert.Contains(t, summary, filesLine(3, 3, 0))
+	assert.Contains(t, summary, env.dataLine(env.totalSize, env.totalSize))
+
+	snap := env.snapshot(t, "first")
+	uploadCount, uploadBytes := env.uploads(t, snap.ID.String())
+	require.Positive(t, uploadCount)
+
+	assert.Contains(t, summary, fmt.Sprintf("Upload: %d blobs, %s in ",
+		uploadCount, env.v.UI.Size(uploadBytes)))
+
+	assert.Equal(t, int64(3), snap.FileCount)
+	assert.Equal(t, env.totalSize, snap.TotalSize)
+	assert.Equal(t, uploadCount, snap.BlobCount)
+	assert.Equal(t, uploadBytes, snap.UploadBytes)
+}
+
+// An incremental backup where a.bin's mtime changed but its content did
+// not: a.bin is backed up again and every one of its chunks is already
+// stored.
+//
+//nolint:paralleltest // installs the global logger via log.Initialize
+func TestSnapshotSummaryIncrementalRunWithDeduplicatedChunks(t *testing.T) {
+	env := newSummaryEnv(t)
+
+	env.backUp(t, "first", false)
+
+	later := time.Now().Add(time.Hour)
+	require.NoError(t, os.Chtimes(env.aPath, later, later))
+
+	summary := env.backUp(t, "second", false)
+
+	assert.Contains(t, summary, filesLine(3, 1, 2))
+	assert.Contains(t, summary, env.dataLine(env.totalSize, env.aSize))
+	assert.NotContains(t, summary, "Upload:")
+
+	snap := env.snapshot(t, "second")
+	compressed, uncompressed := env.referencedBlobSizes(t, snap.ID.String())
+	require.Positive(t, compressed)
+
+	assert.Equal(t, env.totalSize, snap.TotalSize)
+	assert.Zero(t, snap.ChunkCount)
+	assert.Zero(t, snap.BlobCount)
+	assert.Zero(t, snap.UploadBytes)
+	assert.Equal(t, compressed, snap.BlobSize,
+		"blob_size must total the blobs the snapshot references")
+	assert.Equal(t, uncompressed, snap.BlobUncompressedSize)
+}
+
+// Under --cron the progress reporter is off; the upload figures must
+// still reach the summary and the snapshots row. The snapshot has two
+// paths, each backed up by its own scan.
+//
+//nolint:paralleltest // installs the global logger via log.Initialize
+func TestSnapshotSummaryCronRunRecordsUploads(t *testing.T) {
+	env := newSummaryEnv(t)
+
+	summary := env.backUp(t, "split", true)
+
+	snap := env.snapshot(t, "split")
+	uploadCount, uploadBytes := env.uploads(t, snap.ID.String())
+	require.Positive(t, uploadCount)
+
+	assert.Contains(t, summary, filesLine(3, 3, 0))
+	assert.Contains(t, summary, env.dataLine(env.totalSize, env.totalSize))
+	assert.Contains(t, summary, fmt.Sprintf("Upload: %d blobs, %s in ",
+		uploadCount, env.v.UI.Size(uploadBytes)))
+
+	assert.Equal(t, env.totalSize, snap.TotalSize)
+	assert.Equal(t, uploadCount, snap.BlobCount,
+		"blob_count must count each blob once, however many paths the "+
+			"snapshot has")
+	assert.Equal(t, uploadBytes, snap.UploadBytes)
+	assert.GreaterOrEqual(t, snap.UploadDurationMs,
+		uploadCount*summaryUploadDelay.Milliseconds())
+
+	compressed, uncompressed := env.referencedBlobSizes(t, snap.ID.String())
+	require.Positive(t, uncompressed)
+
+	assert.Equal(t, compressed, snap.BlobSize)
+	assert.Equal(t, uncompressed, snap.BlobUncompressedSize)
+	assert.InDelta(t, float64(compressed)/float64(uncompressed),
+		snap.CompressionRatio, 1e-9)
+}