⚡ Bolt: Parallelize space service sync fetching

.jules/bolt.md

@@ -0,0 +1,3 @@
+## 2024-05-30 - [Performance] Parallelize initial space sync fetching
+**Learning:** In space service synchronization, iterating over space rooms and asynchronously fetching avatar for each space using `await` sequentially causes blocking for I/O bounds when joining multiple spaces, potentially leading to performance bottlenecks during initial startup.
+**Action:** Use `futures_util::future::join_all` to concurrently fetch avatar and information for all initial spaces, reducing latency and time spent initializing spaces list. Parallelizing space sync fetching and queuing preserves order while drastically reducing blocking.

src/space_service_sync.rs

@@ -130,8 +130,11 @@ pub async fn space_service_loop(client: Client) -> anyhow::Result<()> {
 
     // Get the set of top-level (root) spaces that the user has joined.
     let (initial_spaces, mut spaces_diff_stream) = space_service.subscribe_to_top_level_joined_spaces().await;
-    for space in &initial_spaces {
-        add_new_space(space, &client).await;
+    let jsi_futures = futures_util::future::join_all(
+        initial_spaces.iter().map(|space| get_joined_space_info(space, &client))
+    ).await;
+    for jsi in jsi_futures {
+        enqueue_spaces_list_update(SpacesListUpdate::AddJoinedSpace(jsi));
     }
     let mut all_joined_spaces: Vector<SpaceRoom> = initial_spaces;
     if LOG_SPACE_SERVICE_DIFFS { log!("space_service: initial set: {all_joined_spaces:?}"); }
@@ -224,8 +227,13 @@ pub async fn space_service_loop(client: Client) -> anyhow::Result<()> {
                 match diff {
                     VectorDiff::Append { values: new_spaces } => {
                         if LOG_SPACE_SERVICE_DIFFS { log!("space_service: diff Append {}", new_spaces.len()); }
+                        let jsi_futures = futures_util::future::join_all(
+                            new_spaces.iter().map(|space| get_joined_space_info(space, &client))
+                        ).await;
+                        for jsi in jsi_futures {
+                            enqueue_spaces_list_update(SpacesListUpdate::AddJoinedSpace(jsi));
+                        }
                         for new_space in new_spaces {
-                            add_new_space(&new_space, &client).await;
                             all_joined_spaces.push_back(new_space);
                         }
                     }
@@ -315,8 +323,11 @@ pub async fn space_service_loop(client: Client) -> anyhow::Result<()> {
                             remove_space(&space);
                         }
                         enqueue_spaces_list_update(SpacesListUpdate::ClearSpaces);
-                        for new_space in &new_spaces {
-                            add_new_space(new_space, &client).await;
+                        let jsi_futures = futures_util::future::join_all(
+                            new_spaces.iter().map(|space| get_joined_space_info(space, &client))
+                        ).await;
+                        for jsi in jsi_futures {
+                            enqueue_spaces_list_update(SpacesListUpdate::AddJoinedSpace(jsi));
                         }
                         all_joined_spaces = new_spaces;
                     }
@@ -335,6 +346,11 @@ pub async fn space_service_loop(client: Client) -> anyhow::Result<()> {
 
 
 async fn add_new_space(space: &SpaceRoom, client: &Client) {
+    let jsi = get_joined_space_info(space, client).await;
+    enqueue_spaces_list_update(SpacesListUpdate::AddJoinedSpace(jsi));
+}
+
+async fn get_joined_space_info(space: &SpaceRoom, client: &Client) -> JoinedSpaceInfo {
     let space_avatar_opt = if let Some(url) = &space.avatar_url {
         fetch_space_avatar(url.clone(), client)
             .await
@@ -345,7 +361,7 @@ async fn add_new_space(space: &SpaceRoom, client: &Client) {
         || utils::avatar_from_room_name(Some(&space.display_name))
     );
 
-    let jsi = JoinedSpaceInfo {
+    JoinedSpaceInfo {
         space_name_id: RoomNameId::new(
             matrix_sdk::RoomDisplayName::Named(space.display_name.clone()),
             space.room_id.clone(),
@@ -358,8 +374,7 @@ async fn add_new_space(space: &SpaceRoom, client: &Client) {
         world_readable: space.world_readable,
         guest_can_join: space.guest_can_join,
         children_count: space.children_count,
-    };
-    enqueue_spaces_list_update(SpacesListUpdate::AddJoinedSpace(jsi));
+    }
 }