Skip no-op payload passes and context lookups without a codec or external storage

changelog/fixed/sprinting-sandbox-sloth.md

@@ -0,0 +1 @@
+Workflow workers without a payload codec or external storage skip the payload codec passes and the per-command serialization-context lookups on every activation and completion, restoring the workflow task and replay performance lost since 1.23.

temporalio/bridge/worker.py

@@ -330,10 +330,11 @@ async def decode_activation(
             _Visitor(data_converter._external_retrieve_payload_sequence), activation
         )
 
-    await CommandAwarePayloadVisitor(
-        skip_search_attributes=True,
-        skip_headers=not decode_headers,
-    ).visit(_Visitor(data_converter._decode_payload_sequence), activation)
+    if data_converter.payload_codec:
+        await CommandAwarePayloadVisitor(
+            skip_search_attributes=True,
+            skip_headers=not decode_headers,
+        ).visit(_Visitor(data_converter._decode_payload_sequence), activation)
 
     return metrics
 
@@ -349,6 +350,10 @@ async def encode_completion(
     Returns:
         Metrics from any external storage store operations that occurred.
     """
+    metrics = temporalio.converter._extstore.StorageOperationMetrics()
+    if not data_converter._has_codec_or_external_storage:
+        return metrics
+
     await CommandAwarePayloadVisitor(
         skip_search_attributes=True,
         skip_headers=not encode_headers,
@@ -357,7 +362,6 @@ async def encode_completion(
         completion,
     )
 
-    metrics = temporalio.converter._extstore.StorageOperationMetrics()
     with metrics.track():
         await CommandAwarePayloadVisitor(
             skip_search_attributes=True,

temporalio/converter/_data_converter.py

@@ -423,10 +423,11 @@ async def _decode_payload_sequence(
             decoded_payloads = await self.payload_codec.decode(decoded_payloads)
         return decoded_payloads
 
-    # Temporary shortcircuit detection while the _decode_* methods may no-op if
-    # a payload codec is not configured. Remove once those paths have more to them.
+    # Without a codec or external storage, the payload sequence methods only reject
+    # external storage references, so workers skip the passes that cannot change a
+    # payload and the per-command context lookups.
     @property
-    def _decode_payload_has_effect(self) -> bool:
+    def _has_codec_or_external_storage(self) -> bool:
         return self.payload_codec is not None or self.external_storage is not None
 
 

temporalio/worker/_workflow.py

@@ -399,7 +399,10 @@ async def _handle_activation(
                     ),
                 ),
             )
-            if workflow:
+            # Resolving a command's context calls into the workflow instance (the
+            # sandbox, when sandboxed) for every payload sequence, and only a codec
+            # or external storage can use it.
+            if workflow and data_converter._has_codec_or_external_storage:
                 data_converter = _CommandAwareDataConverter.create(
                     instance=workflow.instance,
                     context_free_dc=self._data_converter,
@@ -516,7 +519,7 @@ async def _handle_activation(
         completion.run_id = act.run_id
 
         # Encode completion
-        if workflow:
+        if workflow and self._data_converter._has_codec_or_external_storage:
             workflow_context = temporalio.converter.WorkflowSerializationContext(
                 namespace=self._namespace,
                 workflow_id=workflow.workflow_id,

tests/test_serialization_context.py

@@ -67,7 +67,10 @@
 from temporalio.exceptions import ApplicationError, NexusOperationError
 from temporalio.testing import WorkflowEnvironment
 from temporalio.worker import Replayer, Worker
-from temporalio.worker._workflow_instance import UnsandboxedWorkflowRunner
+from temporalio.worker._workflow_instance import (
+    UnsandboxedWorkflowRunner,
+    _WorkflowInstanceImpl,
+)
 from tests.helpers import assert_eq_eventually
 from tests.helpers.nexus import make_nexus_endpoint_name
 from tests.test_extstore import InMemoryTestDriver
@@ -1347,6 +1350,59 @@ async def test_codec_with_context(client: Client):
     del test_traces[workflow_id]
 
 
+async def test_command_context_resolved_only_with_codec_or_external_storage(
+    client: Client, monkeypatch: pytest.MonkeyPatch
+):
+    """Context resolution calls into the workflow instance, which is costly in the
+    sandbox, so workers skip it when no codec or external storage can use it."""
+    lookups = 0
+    get_serialization_context = _WorkflowInstanceImpl.get_serialization_context
+
+    def counting_get_serialization_context(self, command_info):  # type: ignore[reportMissingParameterType]
+        nonlocal lookups
+        lookups += 1
+        return get_serialization_context(self, command_info)
+
+    monkeypatch.setattr(
+        _WorkflowInstanceImpl,
+        "get_serialization_context",
+        counting_get_serialization_context,
+    )
+
+    async def run_workflow(data_converter: DataConverter) -> int:
+        nonlocal lookups
+        lookups = 0
+        workflow_id = str(uuid.uuid4())
+        task_queue = str(uuid.uuid4())
+        client_config = client.config()
+        client_config["data_converter"] = data_converter
+        converter_client = Client(**client_config)
+        async with Worker(
+            converter_client,
+            task_queue=task_queue,
+            workflows=[CodecTestWorkflow],
+            workflow_runner=UnsandboxedWorkflowRunner(),
+        ):
+            await converter_client.execute_workflow(
+                CodecTestWorkflow.run,
+                "data",
+                id=workflow_id,
+                task_queue=task_queue,
+            )
+        test_traces.pop(workflow_id, None)
+        return lookups
+
+    assert await run_workflow(DataConverter.default) == 0
+    assert (
+        await run_workflow(
+            dataclasses.replace(
+                DataConverter.default, payload_codec=PayloadCodecWithContext()
+            )
+        )
+        > 0
+    )
+
+
 # Local activity codec test