perf: batch notification snapshot maintenance (#439)

src/live_snapshot_store.py

@@ -217,13 +217,16 @@ class LiveSnapshotStore:
             connection.commit()
         return self.load()
 
-    def remove_notification(self, notification_id: int) -> LiveSnapshotState:
-        """Filter a confirmed read from every worker and subsequent stale refresh."""
+    def remove_notifications(self, notification_ids: Iterable[int]) -> LiveSnapshotState:
+        """Filter confirmed reads from every worker and subsequent stale refreshes."""
+        read_ids = set(notification_ids)
+        if not read_ids:
+            return self.load()
         with self._connect() as connection:
             connection.execute("BEGIN IMMEDIATE")
-            connection.execute(
+            connection.executemany(
                 "INSERT OR IGNORE INTO live_read_notification VALUES (?)",
-                (notification_id,),
+                ((notification_id,) for notification_id in read_ids),
             )
             row = connection.execute(
                 "SELECT value_json, revisions_json FROM live_snapshot WHERE singleton = 1"
@@ -233,8 +236,9 @@ class LiveSnapshotStore:
             if value is not None and isinstance(value.get("notifications"), list):
                 previous = value["notifications"]
                 retained = [
-                    item for item in previous
-                    if not isinstance(item, dict) or item.get("id") != notification_id
+                    item
+                    for item in previous
+                    if not isinstance(item, dict) or item.get("id") not in read_ids
                 ]
                 if retained != previous:
                     value["notifications"] = retained
@@ -249,6 +253,10 @@ class LiveSnapshotStore:
             connection.commit()
         return self.load()
 
+    def remove_notification(self, notification_id: int) -> LiveSnapshotState:
+        """Filter one confirmed read from every worker and subsequent stale refresh."""
+        return self.remove_notifications([notification_id])
+
     def release_refresh(self, owner: str) -> None:
         """Relinquish a lease that became unnecessary after a coherent recheck."""
         with self._connect() as connection:

src/main.py

@@ -1735,30 +1735,30 @@ def _live_snapshot_payload(
     return payload
 
 
-def _remove_notification_from_live_snapshot(thread_id: int) -> None:
+async def _remove_notifications_from_live_snapshot(thread_ids: list[int]) -> None:
     global _live_snapshot_value, _read_notification_ids
-    _read_notification_ids = _read_notification_ids | {thread_id}
+    read_ids = set(thread_ids)
+    if not read_ids:
+        return
+    _read_notification_ids = _read_notification_ids | read_ids
+    if _live_snapshot_value is not None:
+        retained_notifications = _live_snapshot_value.get("notifications")
+        if isinstance(retained_notifications, list):
+            updated = dict(_live_snapshot_value)
+            updated["notifications"] = [
+                notification
+                for notification in retained_notifications
+                if not isinstance(notification, dict)
+                or notification.get("id") not in read_ids
+            ]
+            if updated["notifications"] != retained_notifications:
+                _live_section_revisions["notifications"] += 1
+            _live_snapshot_value = updated
     try:
-        shared = _live_snapshot_store.remove_notification(thread_id)
-        if shared.value is not None or _live_snapshot_value is None:
-            _apply_shared_live_state(shared)
+        await asyncio.to_thread(_live_snapshot_store.remove_notifications, read_ids)
     except (OSError, sqlite3.Error):
         # The upstream mutation already succeeded; keep process-local filtering.
         pass
-    if _live_snapshot_value is None:
-        return
-    retained_notifications = _live_snapshot_value.get("notifications")
-    if not isinstance(retained_notifications, list):
-        return
-    updated = dict(_live_snapshot_value)
-    updated["notifications"] = [
-        notification
-        for notification in retained_notifications
-        if not isinstance(notification, dict) or notification.get("id") != thread_id
-    ]
-    if updated["notifications"] != retained_notifications:
-        _live_section_revisions["notifications"] += 1
-    _live_snapshot_value = updated
 
 
 def _without_read_notifications(snapshot: dict) -> dict:
@@ -1986,7 +1986,6 @@ async def _mark_notification_read_result(thread_id: int) -> tuple[int, bool]:
         )
     except Exception:
         return thread_id, False
-    _remove_notification_from_live_snapshot(thread_id)
     return thread_id, True
 
 
@@ -2016,6 +2015,9 @@ async def read_notifications(batch: NotificationReadBatch) -> JSONResponse:
         for thread_id, succeeded in [task.result()]
         if succeeded
     }
+    await _remove_notifications_from_live_snapshot(
+        [thread_id for thread_id in thread_ids if thread_id in succeeded_ids]
+    )
     failed = [thread_id for thread_id in thread_ids if thread_id not in succeeded_ids]
     return JSONResponse(
         {
@@ -2116,7 +2118,7 @@ async def read_notification(thread_id: int = PathParam(gt=0)) -> JSONResponse:
             {"error": "The update could not be marked read. Please retry."},
             status_code=503,
         )
-    _remove_notification_from_live_snapshot(thread_id)
+    await _remove_notifications_from_live_snapshot([thread_id])
     return JSONResponse({"id": thread_id, "status": "read"})