Remove dependencies from TaskExecutionSpecification (#5166)

python/ray/_raylet.pyx

@@ -232,14 +232,11 @@ cdef class RayletClient:
     def disconnect(self):
         check_status(self.client.get().Disconnect())
 
-    def submit_task(self, TaskSpec task_spec, execution_dependencies):
+    def submit_task(self, TaskSpec task_spec):
         cdef:
             CObjectID c_id
-            c_vector[CObjectID] c_dependencies
-        for dep in execution_dependencies:
-            c_dependencies.push_back((<ObjectID>dep).native())
         check_status(self.client.get().SubmitTask(
-            c_dependencies, task_spec.task_spec.get()[0]))
+            task_spec.task_spec.get()[0]))
 
     def get_task(self):
         cdef:

python/ray/actor.py

@@ -547,7 +547,7 @@ class ActorHandle(object):
                     actor_counter=self._ray_actor_counter,
                     actor_creation_dummy_object_id=(
                         self._ray_actor_creation_dummy_object_id),
-                    execution_dependencies=[self._ray_actor_cursor],
+                    previous_actor_task_dummy_object_id=self._ray_actor_cursor,
                     new_actor_handles=self._ray_new_actor_handles,
                     # We add one for the dummy return ID.
                     num_return_vals=num_return_vals + 1,

python/ray/includes/libraylet.pxd

@@ -50,9 +50,7 @@ cdef extern from "ray/raylet/raylet_client.h" nogil:
                       c_bool is_worker, const CJobID &job_id,
                       const CLanguage &language)
         CRayStatus Disconnect()
-        CRayStatus SubmitTask(
-            const c_vector[CObjectID] &execution_dependencies,
-            const CTaskSpec &task_spec)
+        CRayStatus SubmitTask(const CTaskSpec &task_spec)
         CRayStatus GetTask(unique_ptr[CTaskSpec] *task_spec)
         CRayStatus TaskDone()
         CRayStatus FetchOrReconstruct(c_vector[CObjectID] &object_ids,

python/ray/includes/task.pxd

@@ -66,6 +66,7 @@ cdef extern from "ray/common/task/task_spec.h" namespace "ray" nogil:
         c_bool IsActorTask() const
         CActorID ActorCreationId() const
         CObjectID ActorCreationDummyObjectId() const
+        CObjectID PreviousActorTaskDummyObjectId() const
         uint64_t MaxActorReconstructions() const
         CActorID ActorId() const
         CActorHandleID ActorHandleId() const
@@ -92,8 +93,10 @@ cdef extern from "ray/common/task/task_util.h" namespace "ray" nogil:
 
         TaskSpecBuilder &SetActorTaskSpec(
             const CActorID &actor_id, const CActorHandleID &actor_handle_id,
-            const CObjectID &actor_creation_dummy_object_id, uint64_t actor_counter,
-            const c_vector[CActorHandleID] &new_handle_ids)
+            const CObjectID &actor_creation_dummy_object_id,
+            const CObjectID &previous_actor_task_dummy_object_id,
+            uint64_t actor_counter,
+            const c_vector[CActorHandleID] &new_handle_ids);
 
         RpcTaskSpec GetMessage()
 

python/ray/includes/task.pxi

@@ -23,6 +23,7 @@ cdef class TaskSpec:
                  int num_returns, TaskID parent_task_id, int parent_counter,
                  ActorID actor_creation_id,
                  ObjectID actor_creation_dummy_object_id,
+                 ObjectID previous_actor_task_dummy_object_id,
                  int32_t max_actor_reconstructions, ActorID actor_id,
                  ActorHandleID actor_handle_id, int actor_counter,
                  new_actor_handles, resource_map, placement_resource_map):
@@ -85,6 +86,7 @@ cdef class TaskSpec:
                 actor_id.native(),
                 actor_handle_id.native(),
                 actor_creation_dummy_object_id.native(),
+                previous_actor_task_dummy_object_id.native(),
                 actor_counter,
                 c_new_actor_handles,
             )
@@ -229,6 +231,13 @@ cdef class TaskSpec:
         return ObjectID(
             self.task_spec.get().ActorCreationDummyObjectId().Binary())
 
+    def previous_actor_task_dummy_object_id(self):
+        """Return the object ID of the previously executed actor task."""
+        if not self.is_actor_task():
+            return ObjectID.nil()
+        return ObjectID(
+            self.task_spec.get().PreviousActorTaskDummyObjectId().Binary())
+
     def actor_id(self):
         """Return the actor ID for this task."""
         if not self.is_actor_task():
@@ -247,13 +256,10 @@ cdef class TaskExecutionSpec:
     cdef:
         unique_ptr[CTaskExecutionSpec] c_spec
 
-    def __init__(self, execution_dependencies):
+    def __init__(self):
         cdef:
             RpcTaskExecutionSpec message;
 
-        for dependency in execution_dependencies:
-            message.add_dependencies(
-                (<ObjectID?>dependency).binary())
         self.c_spec.reset(new CTaskExecutionSpec(message))
 
     @staticmethod
@@ -264,16 +270,6 @@ cdef class TaskExecutionSpec:
         self.c_spec.reset(new CTaskExecutionSpec(string))
         return self
 
-    def dependencies(self):
-        cdef:
-            CObjectID c_id
-            c_vector[CObjectID] dependencies = (
-                self.c_spec.get().ExecutionDependencies())
-        ret = []
-        for c_id in dependencies:
-            ret.append(ObjectID(c_id.Binary()))
-        return ret
-
     def num_forwards(self):
         return self.c_spec.get().NumForwards()
 

python/ray/state.py

@@ -341,6 +341,8 @@ class GlobalState(object):
             "ActorCreationID": task.actor_creation_id().hex(),
             "ActorCreationDummyObjectID": (
                 task.actor_creation_dummy_object_id().hex()),
+            "PreviousActorTaskDummyObjectID": (
+                task.previous_actor_task_dummy_object_id().hex()),
             "ActorCounter": task.actor_counter(),
             "Args": task.arguments(),
             "ReturnObjectIDs": task.returns(),
@@ -356,7 +358,6 @@ class GlobalState(object):
             task_table_data.task.task_execution_spec.SerializeToString())
         return {
             "ExecutionSpec": {
-                "Dependencies": execution_spec.dependencies(),
                 "NumForwards": execution_spec.num_forwards(),
             },
             "TaskSpec": task_spec_info

python/ray/worker.py

@@ -586,8 +586,8 @@ class Worker(object):
                     actor_counter=0,
                     actor_creation_id=None,
                     actor_creation_dummy_object_id=None,
+                    previous_actor_task_dummy_object_id=None,
                     max_actor_reconstructions=0,
-                    execution_dependencies=None,
                     new_actor_handles=None,
                     num_return_vals=None,
                     resources=None,
@@ -611,7 +611,9 @@ class Worker(object):
             actor_creation_dummy_object_id: If this task is an actor method,
                 then this argument is the dummy object ID associated with the
                 actor creation task for the corresponding actor.
-            execution_dependencies: The execution dependencies for this task.
+            previous_actor_task_dummy_object_id: If this task is an actor,
+                then this argument is the dummy object ID associated with the
+                task previously submitted to the corresponding actor.
             num_return_vals: The number of return values this function should
                 have.
             resources: The resource requirements for this task.
@@ -652,10 +654,6 @@ class Worker(object):
                 else:
                     args_for_raylet.append(put(arg))
 
-            # By default, there are no execution dependencies.
-            if execution_dependencies is None:
-                execution_dependencies = []
-
             if new_actor_handles is None:
                 new_actor_handles = []
 
@@ -705,6 +703,7 @@ class Worker(object):
                 self.task_context.task_index,
                 actor_creation_id,
                 actor_creation_dummy_object_id,
+                previous_actor_task_dummy_object_id,
                 max_actor_reconstructions,
                 actor_id,
                 actor_handle_id,
@@ -713,7 +712,7 @@ class Worker(object):
                 resources,
                 placement_resources,
             )
-            self.raylet_client.submit_task(task, execution_dependencies)
+            self.raylet_client.submit_task(task)
 
             return task.returns()
 
@@ -1887,6 +1886,7 @@ def connect(node,
             0,  # parent_counter.
             ActorID.nil(),  # actor_creation_id.
             ObjectID.nil(),  # actor_creation_dummy_object_id.
+            ObjectID.nil(),  # previous_actor_task_dummy_object_id.
             0,  # max_actor_reconstructions.
             ActorID.nil(),  # actor_id.
             ActorHandleID.nil(),  # actor_handle_id.