Record each snapshot's uncompressed size when its backup runs (closes #360)

snapshot list summed the chunks a snapshot reaches through its file rows
in the local index. A file's row is shared by every snapshot that lists
it and rewritten when the file changes, so backing up a changed file
changed every older snapshot's UNCOMPRESSED SIZE.

The backup now takes that total when it records the snapshot's stats,
into a new snapshots column, uncompressed_chunk_size, and snapshot list
reads the column, as it already does for new_chunk_size.

Model: opus-5-5

README.md

@@ -294,7 +294,8 @@ needed.
 of the local index and the backup destination store — with timestamps
 and three sizes per snapshot (compressed remote size; total
 uncompressed chunk size; size of the chunks that snapshot stored that
-were not stored before, recorded when its backup ran).
+were not stored before). Both chunk sizes are recorded when the
+snapshot's backup runs.
 
 Listing the destination store does **not** require the age secret key,
 so it works in vaultik's intended configuration, where the backed-up

docs/DATAMODEL.md

@@ -90,7 +90,7 @@ Stores information about packed, compressed, and encrypted blob files.
 - `created_ts` (INTEGER NOT NULL) - Creation timestamp
 - `finished_ts` (INTEGER) - Finalization timestamp (NULL if in progress)
 - `uncompressed_size` (INTEGER NOT NULL DEFAULT 0) - Total size of chunks before compression
-- `compressed_size` (INTEGER NOT NULL DEFAULT 0) - Size after compression and encryption. Once uploaded, the size of the object in storage: when the blob was already stored, under another compression level or other recipients, this can differ from the size of the local copy
+- `compressed_size` (INTEGER NOT NULL DEFAULT 0) - Size after compression and encryption
 - `uploaded_ts` (INTEGER) - Upload completion timestamp (NULL if not uploaded)
 
 **Purpose:** Tracks blob lifecycle from creation through upload. The UUID primary key allows immediate association of chunks with blobs.
@@ -122,6 +122,7 @@ Tracks backup snapshots.
 - `new_chunk_size` (INTEGER) - Total size of those chunks before compression; `snapshot list` shows it as NEW CHUNK SIZE
 - `blob_count` (INTEGER) - Number of blobs this snapshot created
 - `total_size` (INTEGER) - Total size of all files
+- `uncompressed_chunk_size` (INTEGER) - Total size before compression of the distinct chunks the snapshot's files reference, recorded when its backup ran; `snapshot list` shows it as UNCOMPRESSED SIZE
 - `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
@@ -184,7 +185,7 @@ Tracks blob upload metrics.
    - `UPDATE blobs SET blob_hash = ?, finished_ts = ?` - Finalize blob after packing
 
 4. **Upload**
-   - `UPDATE blobs SET uploaded_ts = ?, compressed_size = ?` - Mark blob as uploaded, with the size of the object in storage (the upload is skipped when the blob is already stored)
+   - `UPDATE blobs SET uploaded_ts = ?` - Mark blob as uploaded
    - `INSERT INTO uploads` - Record upload metrics with snapshot_id
    - `INSERT INTO snapshot_blobs` - Associate blob with snapshot
 

internal/database/blobs.go

@@ -159,16 +159,13 @@ func (r *BlobRepository) UpdateFinished(
 	return nil
 }
 
-// UpdateUploaded marks a blob as uploaded and records the size of the
-// stored object as its compressed size. That size can differ from the
-// local copy's when an identical blob was already stored with another
-// compression level or other recipients.
+// UpdateUploaded marks a blob as uploaded
 func (r *BlobRepository) UpdateUploaded(
-	ctx context.Context, tx *sql.Tx, id string, storedSize int64,
+	ctx context.Context, tx *sql.Tx, id string,
 ) error {
 	query := `
-		UPDATE blobs
-		SET uploaded_ts = ?, compressed_size = ?
+		UPDATE blobs 
+		SET uploaded_ts = ?
 		WHERE id = ?
 	`
 
@@ -176,9 +173,9 @@ func (r *BlobRepository) UpdateUploaded(
 
 	var err error
 	if tx != nil {
-		_, err = tx.ExecContext(ctx, query, now, storedSize, id)
+		_, err = tx.ExecContext(ctx, query, now, id)
 	} else {
-		_, err = r.db.ExecWithLog(ctx, query, now, storedSize, id)
+		_, err = r.db.ExecWithLog(ctx, query, now, id)
 	}
 
 	if err != nil {

internal/database/blobs_test.go

@@ -122,8 +122,8 @@ func TestBlobRepositoryUpdates(t *testing.T) {
 		t.Errorf("expected compressed size 500, got %d", updated.CompressedSize)
 	}
 
-	// Test UpdateUploaded, with a stored object larger than the local copy
-	err = repo.UpdateUploaded(ctx, nil, blob.ID.String(), 600)
+	// Test UpdateUploaded
+	err = repo.UpdateUploaded(ctx, nil, blob.ID.String())
 	if err != nil {
 		t.Fatalf("failed to update blob as uploaded: %v", err)
 	}
@@ -141,10 +141,6 @@ func TestBlobRepositoryUpdates(t *testing.T) {
 	if uploaded.UploadedTS.Before(now.Add(-1 * time.Second)) {
 		t.Error("uploaded timestamp should be around test time")
 	}
-
-	if uploaded.CompressedSize != 600 {
-		t.Errorf("expected the stored size 600, got %d", uploaded.CompressedSize)
-	}
 }
 
 func TestBlobRepositoryDuplicate(t *testing.T) {

internal/database/schema/001.sql

@@ -89,6 +89,7 @@ CREATE TABLE IF NOT EXISTS snapshots (
     new_chunk_size INTEGER NOT NULL DEFAULT 0,
     blob_count INTEGER NOT NULL DEFAULT 0,
     total_size INTEGER NOT NULL DEFAULT 0,
+    uncompressed_chunk_size INTEGER NOT NULL DEFAULT 0,
     blob_size INTEGER NOT NULL DEFAULT 0,
     blob_uncompressed_size INTEGER NOT NULL DEFAULT 0,
     compression_ratio REAL NOT NULL DEFAULT 1.0,

internal/database/snapshots.go

@@ -120,7 +120,11 @@ func (r *SnapshotRepository) UpdateCounts(
 	return nil
 }
 
-// UpdateExtendedStats updates extended statistics for a snapshot
+// UpdateExtendedStats updates extended statistics for a snapshot. It also
+// records the total plaintext size of the distinct chunks the snapshot's
+// files reference. Only the snapshot's own backup can take that total: a
+// file's row is shared by every snapshot that lists it, and a later
+// backup of a changed file rewrites the row with the new chunks.
 func (r *SnapshotRepository) UpdateExtendedStats(
 	ctx context.Context,
 	tx *sql.Tx,
@@ -145,7 +149,17 @@ func (r *SnapshotRepository) UpdateExtendedStats(
 		    compression_level = ?,
 		    upload_bytes = ?,
 		    upload_duration_ms = ?,
-		    new_chunk_size = ?
+		    new_chunk_size = ?,
+		    uncompressed_chunk_size = (
+		        SELECT COALESCE(SUM(c.size), 0)
+		        FROM (
+		            SELECT DISTINCT fc.chunk_hash
+		            FROM snapshot_files sf
+		            JOIN file_chunks fc ON sf.file_id = fc.file_id
+		            WHERE sf.snapshot_id = snapshots.id
+		        ) sc
+		        JOIN chunks c ON sc.chunk_hash = c.chunk_hash
+		    )
 		WHERE id = ?
 	`
 
@@ -570,30 +584,22 @@ func (r *SnapshotRepository) GetSnapshotBlobSizes(
 	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).
+// GetSnapshotUncompressedChunkSize returns the total plaintext size of the
+// distinct chunks the snapshot's files reference, as the snapshot's backup
+// recorded it (see UpdateExtendedStats).
 func (r *SnapshotRepository) GetSnapshotUncompressedChunkSize(
 	ctx context.Context, snapshotID string,
 ) (int64, error) {
-	query := `
-		SELECT COALESCE(SUM(c.size), 0)
-		FROM (
-			SELECT DISTINCT fc.chunk_hash
-			FROM snapshot_files sf
-			JOIN file_chunks fc ON sf.file_id = fc.file_id
-			WHERE sf.snapshot_id = ?
-		) sc
-		JOIN chunks c ON sc.chunk_hash = c.chunk_hash
-	`
+	query := `SELECT uncompressed_chunk_size FROM snapshots WHERE id = ?`
 
-	var totalSize int64
+	var uncompressedChunkSize int64
 
-	err := r.db.conn.QueryRowContext(ctx, query, snapshotID).Scan(&totalSize)
+	err := r.db.conn.QueryRowContext(ctx, query, snapshotID).Scan(&uncompressedChunkSize)
 	if err != nil {
 		return 0, fmt.Errorf("querying uncompressed chunk size: %w", err)
 	}
 
-	return totalSize, nil
+	return uncompressedChunkSize, nil
 }
 
 // GetSnapshotNewChunkSize returns the total plaintext size of the chunks the

internal/snapshot/scanner.go

@@ -1517,8 +1517,7 @@ func (s *Scanner) finalizeProcessPhase(ctx context.Context, result *ScanResult)
 			// snapshot references has uploaded_ts set, so deduplication and
 			// interrupted-run repair treat these blobs as trustworthy.
 			err = s.repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
-				err := s.repos.Blobs.UpdateUploaded(
-					ctx, tx, b.ID, b.Compressed)
+				err := s.repos.Blobs.UpdateUploaded(ctx, tx, b.ID)
 				if err != nil {
 					return fmt.Errorf("marking blob uploaded: %w", err)
 				}
@@ -1554,7 +1553,7 @@ func (s *Scanner) handleBlobReady(
 	blobPath := fmt.Sprintf("blobs/%s/%s/%s",
 		finishedBlob.Hash[:2], finishedBlob.Hash[2:4], finishedBlob.Hash)
 
-	storedSize, blobExists, err := s.uploadBlobIfNeeded(
+	blobExists, err := s.uploadBlobIfNeeded(
 		ctx, blobPath, blobWithReader, startTime, result)
 	if err != nil {
 		s.cleanupBlobTempFile(blobWithReader)
@@ -1562,8 +1561,7 @@ func (s *Scanner) handleBlobReady(
 		return fmt.Errorf("uploading blob %s: %w", finishedBlob.Hash, err)
 	}
 
-	err = s.recordBlobMetadata(
-		ctx, finishedBlob, storedSize, blobExists, startTime)
+	err = s.recordBlobMetadata(ctx, finishedBlob, blobExists, startTime)
 	if err != nil {
 		s.cleanupBlobTempFile(blobWithReader)
 
@@ -1585,22 +1583,20 @@ func (s *Scanner) handleBlobReady(
 }
 
 // uploadBlobIfNeeded uploads the blob to storage if it doesn't already
-// exist. It returns the size of the object in storage, which for an
-// existing object can differ from the local copy's, and whether it
-// already existed.
+// exist, returns whether it existed
 func (s *Scanner) uploadBlobIfNeeded(
 	ctx context.Context,
 	blobPath string,
 	blobWithReader *blob.WithReader,
 	startTime time.Time,
 	result *ScanResult,
-) (int64, bool, error) {
+) (bool, error) {
 	finishedBlob := blobWithReader.FinishedBlob
 
 	// Check if blob already exists (deduplication after restart)
 	destination := s.storage.Info().Location
 
-	stored, err := s.storage.Stat(ctx, blobPath)
+	_, err := s.storage.Stat(ctx, blobPath)
 	if err == nil {
 		log.Info("Blob already exists in storage, skipping upload",
 			"hash", finishedBlob.Hash,
@@ -1609,7 +1605,7 @@ func (s *Scanner) uploadBlobIfNeeded(
 			s.ui.Hex(finishedBlob.Hash), s.ui.Size(finishedBlob.Compressed),
 			s.ui.Path(destination))
 
-		return stored.Size, true, nil
+		return true, nil
 	}
 
 	s.ui.Beginf("Uploading blob %s (%s) to %s.",
@@ -1623,7 +1619,7 @@ func (s *Scanner) uploadBlobIfNeeded(
 	if err != nil {
 		log.Error("Failed to upload blob", "hash", finishedBlob.Hash, "error", err)
 
-		return 0, false, fmt.Errorf("uploading blob to storage: %w", err)
+		return false, fmt.Errorf("uploading blob to storage: %w", err)
 	}
 
 	uploadDuration := time.Since(startTime)
@@ -1654,7 +1650,7 @@ func (s *Scanner) uploadBlobIfNeeded(
 		stats.BytesUploaded.Add(finishedBlob.Compressed)
 	}
 
-	return finishedBlob.Compressed, false, nil
+	return false, nil
 }
 
 // makeUploadProgressCallback creates a progress callback for blob uploads.
@@ -1724,7 +1720,6 @@ func (s *Scanner) makeUploadProgressCallback(
 func (s *Scanner) recordBlobMetadata(
 	ctx context.Context,
 	finishedBlob *blob.FinishedBlob,
-	storedSize int64,
 	blobExists bool,
 	startTime time.Time,
 ) error {
@@ -1736,8 +1731,7 @@ func (s *Scanner) recordBlobMetadata(
 	uploadDuration := time.Since(startTime)
 
 	return s.repos.WithTx(ctx, func(txCtx context.Context, tx *sql.Tx) error {
-		err := s.repos.Blobs.UpdateUploaded(
-			txCtx, tx, finishedBlob.ID, storedSize)
+		err := s.repos.Blobs.UpdateUploaded(txCtx, tx, finishedBlob.ID)
 		if err != nil {
 			return fmt.Errorf("updating blob upload timestamp: %w", err)
 		}

internal/vaultik/reused_blob_verify_test.go

@@ -1,83 +0,0 @@
-package vaultik_test
-
-import (
-	"context"
-	"io"
-	"path/filepath"
-	"testing"
-
-	"filippo.io/age"
-	"github.com/spf13/afero"
-	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/vaultik/internal/log"
-	"sneak.berlin/go/vaultik/internal/ui"
-	"sneak.berlin/go/vaultik/internal/vaultik"
-)
-
-// TestVerifyPassesWhenBackupReusesStoredBlob backs up a file, then backs it
-// up again from an empty local index, as after `database delete`, with an
-// extra age recipient. The second backup builds the same blob, finds it
-// already stored and skips the upload, but its own copy is larger, because
-// age writes a header entry for each recipient. The second snapshot must
-// record the size of the stored object, so shallow and deep verify pass.
-func TestVerifyPassesWhenBackupReusesStoredBlob(t *testing.T) {
-	log.Initialize(log.Config{})
-	t.Parallel()
-
-	fs := afero.NewOsFs()
-	tempDir := t.TempDir()
-
-	dataDir := filepath.Join(tempDir, "source")
-	storeDir := filepath.Join(tempDir, "remote")
-	secondDBPath := filepath.Join(tempDir, "second.sqlite")
-
-	chunkSize := int64(64 * 1024)
-	maxBlobSize := int64(512 * 1024)
-
-	require.NoError(t, fs.MkdirAll(dataDir, 0o755))
-	require.NoError(t, afero.WriteFile(fs,
-		filepath.Join(dataDir, "data.bin"),
-		bytesPattern("reuse-", int(chunkSize*3)), 0o644))
-
-	ctx := context.Background()
-
-	runFileStorageBackup(ctx, t, fs, dataDir, storeDir,
-		filepath.Join(tempDir, "first.sqlite"), chunkSize, maxBlobSize)
-
-	env := setupDedupBackupEnv(
-		ctx, t, fs, storeDir, secondDBPath, chunkSize, maxBlobSize)
-
-	defer func() { _ = env.db.Close() }()
-
-	extra, err := age.GenerateX25519Identity()
-	require.NoError(t, err)
-
-	env.cfg.AgeRecipients = append(env.cfg.AgeRecipients,
-		extra.Recipient().String())
-
-	snapshotID, result := runDedupSnapshot(ctx, t, env.sm, env.makeScanner(),
-		env.cfg.Hostname, "second", dataDir, secondDBPath)
-	require.Positive(t, result.BlobsCreated)
-	require.Zero(t, result.BlobsUploaded,
-		"the second backup should find every blob already stored")
-
-	require.NoError(t, env.db.Close())
-
-	verifier := &vaultik.Vaultik{
-		Config:  env.cfg,
-		Storage: env.storer,
-		Fs:      fs,
-		Stdout:  io.Discard,
-		Stderr:  io.Discard,
-		UI:      ui.NewWithColor(io.Discard, false),
-	}
-	verifier.SetContext(ctx)
-
-	require.NoError(t,
-		verifier.VerifySnapshotWithOptions(snapshotID, &vaultik.VerifyOptions{}),
-		"shallow verify should pass")
-	require.NoError(t,
-		verifier.VerifySnapshotWithOptions(snapshotID,
-			&vaultik.VerifyOptions{Deep: true}),
-		"deep verify should pass")
-}

internal/vaultik/snapshot_list_test.go

@@ -483,13 +483,14 @@ func TestListSnapshots_UnreadableManifestDoesNotHideOthers(t *testing.T) {
 //
 //nolint:tagliatelle // snake_case is the established output format
 type listJSONRow struct {
-	ID             string `json:"id"`
-	RemoteKey      string `json:"remote_key"`
-	Timestamp      string `json:"timestamp"`
-	CompressedSize int64  `json:"compressed_size"`
-	NewChunkSize   int64  `json:"new_chunk_size"`
-	LocallyTracked bool   `json:"locally_tracked"`
-	RemotePresent  *bool  `json:"remote_present"`
+	ID               string `json:"id"`
+	RemoteKey        string `json:"remote_key"`
+	Timestamp        string `json:"timestamp"`
+	CompressedSize   int64  `json:"compressed_size"`
+	UncompressedSize int64  `json:"uncompressed_size"`
+	NewChunkSize     int64  `json:"new_chunk_size"`
+	LocallyTracked   bool   `json:"locally_tracked"`
+	RemotePresent    *bool  `json:"remote_present"`
 }
 
 // decodeListJSON parses the command's stdout, which must contain

internal/vaultik/uncompressed_size_test.go

@@ -0,0 +1,85 @@
+package vaultik_test
+
+import (
+	"bytes"
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/vaultik/internal/database"
+	"sneak.berlin/go/vaultik/internal/log"
+	"sneak.berlin/go/vaultik/internal/storage"
+	"sneak.berlin/go/vaultik/internal/vaultik"
+)
+
+// TestUncompressedSizeOfChangedFileStaysFixed covers
+// https://git.eeqj.de/sneak/vaultik/issues/360. A backup that changes a
+// file leaves the earlier snapshot's UNCOMPRESSED SIZE as it was when that
+// snapshot's backup completed. The file's row in the local index is shared
+// by both snapshots and rewritten by the second backup.
+func TestUncompressedSizeOfChangedFileStaysFixed(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	fs := afero.NewOsFs()
+	tempDir := t.TempDir()
+	dataDir := filepath.Join(tempDir, "src")
+	dbPath := filepath.Join(tempDir, "index.sqlite")
+	changedPath := filepath.Join(dataDir, "changed.bin")
+
+	ctx := context.Background()
+	files := writeFaultSourceTree(t, fs, dataDir)
+	cfg := changedFileConfig(dataDir, dbPath)
+
+	appendRandomBytes(t, fs, files, changedPath, appendedFileSize)
+
+	store, err := storage.NewFileStorer(filepath.Join(tempDir, "remote"))
+	require.NoError(t, err)
+
+	db, err := database.New(ctx, dbPath)
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = db.Close() })
+
+	repos := database.NewRepositories(db)
+	v := newBackupVaultik(ctx, cfg, store, repos, db, fs)
+
+	require.NoError(t, backUp(v, "first"))
+
+	// With nothing to compare against, sizeOfNewChunks totals every
+	// distinct chunk of the files.
+	firstID := localSnapshotID(ctx, t, repos, "first")
+	firstSize := sizeOfNewChunks(t, files, nil)
+	require.Equal(t, firstSize, listedUncompressedSizes(t, v)[firstID],
+		"the first snapshot must count the chunks of every file it holds")
+
+	appendRandomBytes(t, fs, files, changedPath, faultChunkSize)
+	require.NoError(t, backUp(v, "second"))
+
+	secondID := localSnapshotID(ctx, t, repos, "second")
+	sizes := listedUncompressedSizes(t, v)
+	assert.Equal(t, firstSize, sizes[firstID],
+		"a later backup must not change the first snapshot's figure")
+	assert.Equal(t, sizeOfNewChunks(t, files, nil), sizes[secondID],
+		"the second snapshot must count the changed file's chunks")
+}
+
+// listedUncompressedSizes runs `snapshot list --json` and returns each
+// listed snapshot's uncompressed_size by snapshot ID.
+func listedUncompressedSizes(t *testing.T, v *vaultik.Vaultik) map[string]int64 {
+	t.Helper()
+
+	var out bytes.Buffer
+
+	v.Stdout = &out
+	require.NoError(t, v.ListSnapshots(true))
+
+	sizes := make(map[string]int64)
+	for _, row := range decodeListJSON(t, out.String()) {
+		sizes[row.ID] = row.UncompressedSize
+	}
+
+	return sizes
+}