Fix: Handle PostgreSQL cached plan errors during rolling deployments

- Add _query_first_with_cached_plan_fallback() helper function to handle
  'cached plan must not change result type' errors
- This error occurs when schema changes (migrations) are applied during
  rolling deployments while old pods have cached query plans
- The fix automatically retries queries with modified SQL to force
  PostgreSQL to create fresh plans based on the new schema
- Addresses issue caused by migration 20260107111013_add_router_settings_to_keys_teams
  which added router_settings column to LiteLLM_VerificationToken table
- The combined_view query uses SELECT v.* which is vulnerable to schema changes

litellm/proxy/utils.py

@@ -2214,6 +2214,45 @@ class PrismaClient:
 
             raise e
 
+    async def _query_first_with_cached_plan_fallback(
+        self, sql_query: str
+    ) -> Optional[dict]:
+        """
+        Execute a query with automatic fallback for PostgreSQL cached plan errors.
+        
+        This handles the "cached plan must not change result type" error that occurs
+        during rolling deployments when schema changes are applied while old pods
+        still have cached query plans expecting the old schema.
+        
+        Args:
+            sql_query: SQL query string to execute
+            
+        Returns:
+            Query result or None
+            
+        Raises:
+            Original exception if not a cached plan error
+        """
+        try:
+            return await self.db.query_first(query=sql_query)
+        except Exception as e:
+            error_str = str(e)
+            if "cached plan must not change result type" in error_str:
+                # Force PostgreSQL to re-plan by invalidating the cache
+                # Add a unique comment to make the query different
+                sql_query_retry = sql_query.replace(
+                    "SELECT",
+                    f"SELECT /* cache_invalidated_{int(time.time() * 1000)} */"
+                )
+                verbose_proxy_logger.warning(
+                    "PostgreSQL cached plan error detected for token lookup, "
+                    "retrying with fresh plan. This may occur during rolling deployments "
+                    "when schema changes are applied."
+                )
+                return await self.db.query_first(query=sql_query_retry)
+            else:
+                raise
+
     @backoff.on_exception(
         backoff.expo,
         Exception,  # base exception to catch for the backoff
@@ -2545,7 +2584,7 @@ class PrismaClient:
                         WHERE v.token = '{token}'
                     """
 
-                    response = await self.db.query_first(query=sql_query)
+                    response = await self._query_first_with_cached_plan_fallback(sql_query)
 
                     if response is not None:
                         if response["team_models"] is None: