diff --git a/src/frontend/src/optimizer/plan_node/stream_source_scan.rs b/src/frontend/src/optimizer/plan_node/stream_source_scan.rs
index 7016ca4ccb56..dc1e1d33a7aa 100644
--- a/src/frontend/src/optimizer/plan_node/stream_source_scan.rs
+++ b/src/frontend/src/optimizer/plan_node/stream_source_scan.rs
@@ -151,7 +151,6 @@ impl StreamSourceScan {
                     .to_internal_table_prost(),
             ),
             info: Some(source_catalog.info.clone()),
-            // XXX: what's the usage of this?
             row_id_index: self.core.row_id_index.map(|index| index as _),
             columns: self
                 .core
diff --git a/src/meta/src/controller/fragment.rs b/src/meta/src/controller/fragment.rs
index 1ede0941ba98..cafa6ced898a 100644
--- a/src/meta/src/controller/fragment.rs
+++ b/src/meta/src/controller/fragment.rs
@@ -1089,6 +1089,24 @@ impl CatalogController {
         Ok(actors)
     }
 
+    /// Get the actor ids, and each actor's upstream actor ids of the fragment with `fragment_id` with `Running` status.
+    pub async fn get_running_actors_and_upstream_of_fragment(
+        &self,
+        fragment_id: FragmentId,
+    ) -> MetaResult<Vec<ActorId>> {
+        let inner = self.inner.read().await;
+        let actors: Vec<(ActorId, Vec<ActorId>)> = Actor::find()
+            .select_only()
+            .column(actor::Column::ActorId)
+            .column(actor::Column::UpstreamActorIds)
+            .filter(actor::Column::FragmentId.eq(fragment_id))
+            .filter(actor::Column::Status.eq(ActorStatus::Running))
+            .into_tuple()
+            .all(&inner.db)
+            .await?;
+        Ok(actors)
+    }
+
     pub async fn get_actors_by_job_ids(&self, job_ids: Vec<ObjectId>) -> MetaResult<Vec<ActorId>> {
         let inner = self.inner.read().await;
         let actors: Vec<ActorId> = Actor::find()
diff --git a/src/meta/src/manager/catalog/fragment.rs b/src/meta/src/manager/catalog/fragment.rs
index 01ac5379bab5..56873c2829a7 100644
--- a/src/meta/src/manager/catalog/fragment.rs
+++ b/src/meta/src/manager/catalog/fragment.rs
@@ -1027,7 +1027,8 @@ impl FragmentManager {
         bail!("fragment not found: {}", fragment_id)
     }
 
-    pub async fn get_running_actors_and_upstream_fragment_of_fragment(
+    /// Get the actor ids, and each actor's upstream actor ids of the fragment with `fragment_id` with `Running` status.
+    pub async fn get_running_actors_and_upstream_of_fragment(
         &self,
         fragment_id: FragmentId,
     ) -> MetaResult<HashSet<(ActorId, Vec<ActorId>)>> {
diff --git a/src/meta/src/manager/metadata.rs b/src/meta/src/manager/metadata.rs
index 6417343f7927..848547e47a62 100644
--- a/src/meta/src/manager/metadata.rs
+++ b/src/meta/src/manager/metadata.rs
@@ -621,11 +621,21 @@ impl MetadataManager {
         match self {
             MetadataManager::V1(mgr) => {
                 mgr.fragment_manager
-                    .get_running_actors_and_upstream_fragment_of_fragment(id)
+                    .get_running_actors_and_upstream_of_fragment(id)
                     .await
             }
-            MetadataManager::V2(_mgr) => {
-                todo!()
+            MetadataManager::V2(mgr) => {
+                let actor_ids = mgr
+                    .catalog_controller
+                    .get_running_actors_and_upstream_of_fragment(id)
+                    .await?;
+                Ok(actor_ids.into_iter().map(|(id, actors)| {
+                    (
+                        id as ActorId,
+                        actors.into_iter().map(|id| id as ActorId).collect(),
+                    )
+                        .collect()
+                }))
             }
         }
     }
diff --git a/src/meta/src/stream/scale.rs b/src/meta/src/stream/scale.rs
index f5d4a2ec5da0..baa10428a084 100644
--- a/src/meta/src/stream/scale.rs
+++ b/src/meta/src/stream/scale.rs
@@ -1232,9 +1232,9 @@ impl ScaleController {
                     .await?;
 
                 fragment_stream_source_actor_splits.insert(*fragment_id, actor_splits);
-                todo!("migrate_splits_backfill");
             }
         }
+        // TODO: support migrate splits for SourceBackfill
 
         // Generate fragment reschedule plan
         let mut reschedule_fragment: HashMap<FragmentId, Reschedule> =
diff --git a/src/meta/src/stream/stream_manager.rs b/src/meta/src/stream/stream_manager.rs
index 7cb85d91af7d..5b1720c9edad 100644
--- a/src/meta/src/stream/stream_manager.rs
+++ b/src/meta/src/stream/stream_manager.rs
@@ -462,7 +462,6 @@ impl GlobalStreamManager {
             }
 
             let dummy_table_id = table_fragments.table_id();
-            // TODO: does this need change? for replace_table
             let init_split_assignment =
                 self.source_manager.allocate_splits(&dummy_table_id).await?;
 
@@ -534,7 +533,6 @@ impl GlobalStreamManager {
             .await?;
 
         let dummy_table_id = table_fragments.table_id();
-        // TODO: does this need change? for replace_table
         let init_split_assignment = self.source_manager.allocate_splits(&dummy_table_id).await?;
 
         if let Err(err) = self