@@ -534,12 +534,14 @@ async def append_event(self, session: Session, event: Event) -> Event:
 
     # Pre-analyze which state scopes have deltas so we only acquire
     # FOR UPDATE locks on rows that will actually be written.
-    has_app_delta = False
-    has_user_delta = False
+    # The result is reused later to avoid calling extract_state_delta twice.
+    state_deltas = None
     if event.actions and event.actions.state_delta:
-      pre_deltas = _session_util.extract_state_delta(event.actions.state_delta)
-      has_app_delta = bool(pre_deltas.get("app"))
-      has_user_delta = bool(pre_deltas.get("user"))
+      state_deltas = _session_util.extract_state_delta(
+          event.actions.state_delta
+      )
+    has_app_delta = bool(state_deltas and state_deltas.get("app"))
+    has_user_delta = bool(state_deltas and state_deltas.get("user"))
 
     async with self._with_session_lock(
         app_name=session.app_name,
@@ -609,11 +611,8 @@ async def append_event(self, session: Session, event: Event) -> Event:
           storage_events = [e async for e in result]
           session.events = [e.to_event() for e in storage_events]
 
-        # Extract state delta
-        if event.actions and event.actions.state_delta:
-          state_deltas = _session_util.extract_state_delta(
-              event.actions.state_delta
-          )
+        # Apply state deltas (reusing pre-analyzed result from above)
+        if state_deltas:
           app_state_delta = state_deltas["app"]
           user_state_delta = state_deltas["user"]
           session_state_delta = state_deltas["session"]