fix: Address review feedback for async event loop and API compatibility

abhijeet-dhumal · cursoragent · abhijeet-dhumal · commit 063eeb2dd03f · 2026-02-25T19:46:38.000+05:30
1. Wrap response_to_dict_fast in run_in_threadpool to avoid blocking
   the async event loop during CPU-bound serialization (fixes concurrency
   under high load)

2. Omit event_timestamps key when empty to match MessageToDict behavior
   (API compatibility - MessageToDict omits empty repeated fields)

Co-authored-by: Cursor &lt;cursoragent@cursor.com&gt;
diff --git a/sdk/python/feast/feature_server.py b/sdk/python/feast/feature_server.py
@@ -341,7 +341,7 @@ async def get_online_features(request: GetOnlineFeaturesRequest) -> ORJSONRespon
                 lambda: store.get_online_features(**read_params)  # type: ignore
             )
 
-        response_dict = response_to_dict_fast(response.proto)
+        response_dict = await run_in_threadpool(response_to_dict_fast, response.proto)
         return ORJSONResponse(content=response_dict)
 
     @app.post(
@@ -370,7 +370,7 @@ async def retrieve_online_documents(
                 lambda: store.retrieve_online_documents(**read_params)  # type: ignore
             )
 
-        response_dict = response_to_dict_fast(response.proto)
+        response_dict = await run_in_threadpool(response_to_dict_fast, response.proto)
         return ORJSONResponse(content=response_dict)
 
     @app.post("/push", dependencies=[Depends(inject_user_details)])
diff --git a/sdk/python/feast/feature_server_utils.py b/sdk/python/feast/feature_server_utils.py
@@ -29,11 +29,16 @@ def response_to_dict_fast(response: GetOnlineFeaturesResponse) -> Dict[str, Any]
                 "statuses": [
                     _STATUS_NAMES.get(s, "INVALID") for s in feature_vector.statuses
                 ],
-                "event_timestamps": [
-                    _timestamp_to_str(ts) for ts in feature_vector.event_timestamps
-                ]
-                if feature_vector.event_timestamps
-                else [],
+                **(
+                    {
+                        "event_timestamps": [
+                            _timestamp_to_str(ts)
+                            for ts in feature_vector.event_timestamps
+                        ]
+                    }
+                    if feature_vector.event_timestamps
+                    else {}
+                ),
             }
             for feature_vector in response.results
         ]

Original file line number	Diff line number	Diff line change
`@@ -341,7 +341,7 @@ async def get_online_features(request: GetOnlineFeaturesRequest) -> ORJSONRespon`
`341`	`341`	`lambda: store.get_online_features(**read_params) # type: ignore`
`342`	`342`	`)`
`343`	`343`
`344`		`- response_dict = response_to_dict_fast(response.proto)`
	`344`	`+ response_dict = await run_in_threadpool(response_to_dict_fast, response.proto)`
`345`	`345`	`return ORJSONResponse(content=response_dict)`
`346`	`346`
`347`	`347`	`@app.post(`
`@@ -370,7 +370,7 @@ async def retrieve_online_documents(`
`370`	`370`	`lambda: store.retrieve_online_documents(**read_params) # type: ignore`
`371`	`371`	`)`
`372`	`372`
`373`		`- response_dict = response_to_dict_fast(response.proto)`
	`373`	`+ response_dict = await run_in_threadpool(response_to_dict_fast, response.proto)`
`374`	`374`	`return ORJSONResponse(content=response_dict)`
`375`	`375`
`376`	`376`	`@app.post("/push", dependencies=[Depends(inject_user_details)])`