Only update litestream_seq if size is below WAL header size

db.go

@@ -145,40 +145,6 @@ func NewDB(path string) *DB {
 	return db
 }
 
-// NewDB returns a new instance of DB for a given path.
-func NewLSDB(path string, metapath string) *DB {
-	_, file := filepath.Split(path)
-
-	db := &DB{
-		path:     path,
-		metaPath: filepath.Join(metapath, "."+file+MetaDirSuffix),
-		notify:   make(chan struct{}),
-
-		MinCheckpointPageN: DefaultMinCheckpointPageN,
-		MaxCheckpointPageN: DefaultMaxCheckpointPageN,
-		TruncatePageN:      DefaultTruncatePageN,
-		CheckpointInterval: DefaultCheckpointInterval,
-		MonitorInterval:    DefaultMonitorInterval,
-		Logger:             slog.With("db", path),
-	}
-
-	db.dbSizeGauge = dbSizeGaugeVec.WithLabelValues(db.path)
-	db.walSizeGauge = walSizeGaugeVec.WithLabelValues(db.path)
-	db.totalWALBytesCounter = totalWALBytesCounterVec.WithLabelValues(db.path)
-	db.shadowWALIndexGauge = shadowWALIndexGaugeVec.WithLabelValues(db.path)
-	db.shadowWALSizeGauge = shadowWALSizeGaugeVec.WithLabelValues(db.path)
-	db.syncNCounter = syncNCounterVec.WithLabelValues(db.path)
-	db.syncErrorNCounter = syncErrorNCounterVec.WithLabelValues(db.path)
-	db.syncSecondsCounter = syncSecondsCounterVec.WithLabelValues(db.path)
-	db.checkpointNCounterVec = checkpointNCounterVec.MustCurryWith(prometheus.Labels{"db": db.path})
-	db.checkpointErrorNCounterVec = checkpointErrorNCounterVec.MustCurryWith(prometheus.Labels{"db": db.path})
-	db.checkpointSecondsCounterVec = checkpointSecondsCounterVec.MustCurryWith(prometheus.Labels{"db": db.path})
-
-	db.ctx, db.cancel = context.WithCancel(context.Background())
-
-	return db
-}
-
 // SQLDB returns a reference to the underlying sql.DB connection.
 func (db *DB) SQLDB() *sql.DB {
 	return db.db
@@ -663,7 +629,7 @@ func (db *DB) acquireReadLock() error {
 	}
 
 	// Execute read query to obtain read lock.
-	if _, err := tx.ExecContext(db.ctx, `SELECT COUNT(1) FROM _litestream_seq;`); err != nil {
+	if _, err := tx.ExecContext(context.Background(), `SELECT COUNT(1) FROM _litestream_seq;`); err != nil {
 		_ = tx.Rollback()
 		return err
 	}
@@ -683,6 +649,10 @@ func (db *DB) releaseReadLock() error {
 	// Rollback & clear read transaction.
 	err := db.rtx.Rollback()
 	db.rtx = nil
+
+	if errors.Is(err, context.Canceled) {
+		err = nil
+	}
 	return err
 }
 
@@ -727,7 +697,7 @@ func (db *DB) createGeneration() (string, error) {
 
 	// Atomically write generation name as current generation.
 	generationNamePath := db.GenerationNamePath()
-	mode := os.FileMode(0600)
+	mode := os.FileMode(0o600)
 	if db.fileInfo != nil {
 		mode = db.fileInfo.Mode()
 	}
@@ -1020,7 +990,7 @@ func (db *DB) initShadowWALFile(filename string) (int64, error) {
 	}
 
 	// Write header to new WAL shadow file.
-	mode := os.FileMode(0600)
+	mode := os.FileMode(0o600)
 	if fi := db.fileInfo; fi != nil {
 		mode = fi.Mode()
 	}
@@ -1056,7 +1026,7 @@ func (db *DB) copyToShadowWAL(filename string) (origWalSize int64, newSize int64
 	}
 	origWalSize = frameAlign(fi.Size(), db.pageSize)
 
-	w, err := os.OpenFile(filename, os.O_RDWR, 0666)
+	w, err := os.OpenFile(filename, os.O_RDWR, 0o666)
 	if err != nil {
 		return 0, 0, err
 	}
@@ -1339,7 +1309,7 @@ func (db *DB) Checkpoint(ctx context.Context, mode string) (err error) {
 	return db.checkpoint(ctx, generation, mode)
 }
 
-// checkpoint performs a checkpoint on the WAL file and initializes a
+// checkpointAndInit performs a checkpoint on the WAL file and initializes a
 // new shadow WAL file.
 func (db *DB) checkpoint(ctx context.Context, generation, mode string) error {
 	// Try getting a checkpoint lock, will fail during snapshots.
@@ -1368,7 +1338,7 @@ func (db *DB) checkpoint(ctx context.Context, generation, mode string) error {
 	// a new page is written.
 	if err := db.execCheckpoint(mode); err != nil {
 		return err
-	} else if _, err = db.db.Exec(`INSERT INTO _litestream_seq (id, seq) VALUES (1, 1) ON CONFLICT (id) DO UPDATE SET seq = seq + 1`); err != nil {
+	} else if err := db.ensureWALExists(); err != nil {
 		return err
 	}
 
@@ -1458,7 +1428,7 @@ func (db *DB) execCheckpoint(mode string) (err error) {
 
 	// Reacquire the read lock immediately after the checkpoint.
 	if err := db.acquireReadLock(); err != nil {
-		return fmt.Errorf("release read lock: %w", err)
+		return fmt.Errorf("acquire read lock: %w", err)
 	}
 
 	return nil

db_test.go

@@ -375,7 +375,7 @@ func TestDB_Sync(t *testing.T) {
 		shadowWALPath := db.ShadowWALPath(pos0.Generation, pos0.Index)
 		if buf, err := os.ReadFile(shadowWALPath); err != nil {
 			t.Fatal(err)
-		} else if err := os.WriteFile(shadowWALPath, append(buf[:litestream.WALHeaderSize-8], 0, 0, 0, 0, 0, 0, 0, 0), 0600); err != nil {
+		} else if err := os.WriteFile(shadowWALPath, append(buf[:litestream.WALHeaderSize-8], 0, 0, 0, 0, 0, 0, 0, 0), 0o600); err != nil {
 			t.Fatal(err)
 		}
 
@@ -552,12 +552,7 @@ func TestDB_Sync(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		// Ensure position is now on the second index.
-		if pos, err := db.Pos(); err != nil {
-			t.Fatal(err)
-		} else if got, want := pos.Index, 1; got != want {
-			t.Fatalf("Index=%v, want %v", got, want)
-		}
+		// NOTE: The minimum checkpoint may only do a PASSIVE checkpoint so we can't guarantee a rollover.
 	})
 
 	// Ensure DB checkpoints after interval.
@@ -581,13 +576,6 @@ func TestDB_Sync(t *testing.T) {
 		} else if err := db.Sync(context.Background()); err != nil {
 			t.Fatal(err)
 		}
-
-		// Ensure position is now on the second index.
-		if pos, err := db.Pos(); err != nil {
-			t.Fatal(err)
-		} else if got, want := pos.Index, 1; got != want {
-			t.Fatalf("Index=%v, want %v", got, want)
-		}
 	})
 }
 

replica_test.go

@@ -50,6 +50,10 @@ func TestReplica_Sync(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	if err := db.Checkpoint(context.Background(), litestream.CheckpointModeTruncate); err != nil {
+		t.Fatal(err)
+	}
+
 	c := file.NewReplicaClient(t.TempDir())
 	r := litestream.NewReplica(db, "")
 	c.Replica, r.Client = r, c
@@ -142,7 +146,7 @@ func TestReplica_Snapshot(t *testing.T) {
 		t.Fatal(err)
 	} else if info, err := r.Snapshot(context.Background()); err != nil {
 		t.Fatal(err)
-	} else if got, want := info.Pos(), nextIndex(pos0); got != want {
+	} else if got, want := info.Pos(), pos0.Truncate(); got != want {
 		t.Fatalf("pos=%s, want %s", got, want)
 	}
 
@@ -166,20 +170,18 @@ func TestReplica_Snapshot(t *testing.T) {
 		t.Fatal(err)
 	} else if info, err := r.Snapshot(context.Background()); err != nil {
 		t.Fatal(err)
-	} else if got, want := info.Pos(), nextIndex(pos1); got != want {
+	} else if got, want := info.Pos(), pos1.Truncate(); got != want {
 		t.Fatalf("pos=%v, want %v", got, want)
 	}
 
-	// Verify three snapshots exist.
+	// Verify snapshots exist.
 	if infos, err := r.Snapshots(context.Background()); err != nil {
 		t.Fatal(err)
-	} else if got, want := len(infos), 3; got != want {
+	} else if got, want := len(infos), 2; got != want {
 		t.Fatalf("len=%v, want %v", got, want)
 	} else if got, want := infos[0].Pos(), pos0.Truncate(); got != want {
 		t.Fatalf("info[0]=%s, want %s", got, want)
-	} else if got, want := infos[1].Pos(), nextIndex(pos0); got != want {
+	} else if got, want := infos[1].Pos(), pos1.Truncate(); got != want {
 		t.Fatalf("info[1]=%s, want %s", got, want)
-	} else if got, want := infos[2].Pos(), nextIndex(pos1); got != want {
-		t.Fatalf("info[2]=%s, want %s", got, want)
 	}
 }

s3/replica_client.go

@@ -136,12 +136,12 @@ func (c *ReplicaClient) findBucketRegion(ctx context.Context, bucket string) (st
 
 	// Fetch bucket location, if possible. Must be bucket owner.
 	// This call can return a nil location which means it's in us-east-1.
-	if out, err := s3.New(sess).HeadBucketWithContext(ctx, &s3.HeadBucketInput{
+	if out, err := s3.New(sess).GetBucketLocation(&s3.GetBucketLocationInput{
 		Bucket: aws.String(bucket),
 	}); err != nil {
 		return "", err
-	} else if out.BucketRegion != nil {
-		return *out.BucketRegion, nil
+	} else if out.LocationConstraint != nil {
+		return *out.LocationConstraint, nil
 	}
 	return DefaultRegion, nil
 }