update

backend/app/db.py

@@ -25,11 +25,14 @@ CREATE INDEX IF NOT EXISTS items_seq ON items(seq);
 # Große Datei-Uploads halten die Datenbank sekundenlang. WAL lässt Leser derweil durch,
 # Schreiber warten bis zu 60 s statt mit "database is locked" abzubrechen.
 @contextmanager
-def connect():
+def connect(write=False):
     DB_PATH.parent.mkdir(parents=True, exist_ok=True)
     conn = sqlite3.connect(DB_PATH, timeout=60)
     conn.row_factory = sqlite3.Row
     try:
+        # Schreiber nacheinander: so greifen zwei Anhänge an dieselbe Datei nie gleichzeitig zu
+        if write:
+            conn.execute("BEGIN IMMEDIATE")
         yield conn
         conn.commit()
     finally:
@@ -78,21 +81,6 @@ def since(conn, collection, seq):
     return [json.loads(r["data"]) for r in rows]
 
 
-def since_paged(conn, collection, seq, max_bytes):
-    """Wie since, aber höchstens max_bytes Daten. Gibt (Einträge, letzter seq, mehr da) zurück."""
-    rows = conn.execute(
-        "SELECT data, seq FROM items WHERE collection = ? AND seq > ? ORDER BY seq", (collection, seq)
-    )
-    items, size, last = [], 0, seq
-    for r in rows:
-        if items and size + len(r["data"]) > max_bytes:
-            return items, last, True
-        items.append(json.loads(r["data"]))
-        size += len(r["data"])
-        last = r["seq"]
-    return items, last, False
-
-
 def alive(conn, collection):
     rows = conn.execute(
         "SELECT data FROM items WHERE collection = ? AND deleted = 0 ORDER BY id", (collection,)