Handle display name changes more efficiently (#6585)

backend/canisters/community/CHANGELOG.md

@@ -13,6 +13,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Ensure members marked as lapsed in updates queries ([#6573](https://github.com/open-chat-labs/open-chat/pull/6573))
 - Reduce size of responses by only returning UserIds for basic members ([#6577](https://github.com/open-chat-labs/open-chat/pull/6577))
 - Remove `transaction` from serialized PrizeWinner messages ([#6578](https://github.com/open-chat-labs/open-chat/pull/6578))
+- Handle display name changes more efficiently ([#6585](https://github.com/open-chat-labs/open-chat/pull/6585))
 
 ## [[2.0.1378](https://github.com/open-chat-labs/open-chat/releases/tag/v2.0.1378-community)] - 2024-10-10
 

backend/canisters/community/impl/src/lifecycle/post_upgrade.rs

@@ -1,7 +1,8 @@
 use crate::jobs::import_groups::finalize_group_import;
 use crate::lifecycle::{init_env, init_state};
 use crate::memory::get_upgrades_memory;
-use crate::{read_state, Data};
+use crate::model::members::MemberUpdate;
+use crate::{mutate_state, read_state, Data};
 use canister_logger::LogEntry;
 use canister_tracing_macros::trace;
 use community_canister::post_upgrade::Args;
@@ -29,6 +30,25 @@ fn post_upgrade(args: Args) {
         finalize_group_import(group_id);
     }
 
+    // TODO: Delete after release
+    mutate_state(|state| {
+        let updated_members: Vec<_> = state
+            .data
+            .members
+            .iter()
+            .map(|m| (m.user_id, m.display_name().timestamp))
+            .filter(|(_, ts)| *ts > 0)
+            .collect();
+
+        for (user_id, timestamp) in updated_members {
+            state
+                .data
+                .members
+                .updates
+                .insert((timestamp, user_id, MemberUpdate::DisplayNameChanged));
+        }
+    });
+
     info!(version = %args.wasm_version, "Post-upgrade complete");
 
     read_state(|state| {

backend/canisters/community/impl/src/model/members.rs

@@ -15,14 +15,15 @@ const MAX_MEMBERS_PER_COMMUNITY: u32 = 100_000;
 #[derive(Serialize, Deserialize)]
 pub struct CommunityMembers {
     members: HashMap<UserId, CommunityMemberInternal>,
-    display_names_last_updated: TimestampMillis,
     user_groups: UserGroups,
     // This includes the userIds of community members and also users invited to the community
     principal_to_user_id_map: HashMap<Principal, UserId>,
     blocked: HashSet<UserId>,
     admin_count: u32,
     owner_count: u32,
-    updates: BTreeSet<(TimestampMillis, UserId, MemberUpdate)>,
+    // TODO: Remove pub after release
+    #[serde(default)]
+    pub updates: BTreeSet<(TimestampMillis, UserId, MemberUpdate)>,
 }
 
 impl CommunityMembers {
@@ -50,7 +51,6 @@ impl CommunityMembers {
 
         CommunityMembers {
             members: vec![(creator_user_id, member)].into_iter().collect(),
-            display_names_last_updated: now,
             user_groups: UserGroups::default(),
             principal_to_user_id_map: vec![(creator_principal, creator_user_id)].into_iter().collect(),
             blocked: HashSet::new(),
@@ -252,10 +252,6 @@ impl CommunityMembers {
         self.user_groups.last_updated()
     }
 
-    pub fn display_names_last_updated(&self) -> TimestampMillis {
-        self.display_names_last_updated
-    }
-
     pub fn update_user_principal(&mut self, old_principal: Principal, new_principal: Principal) {
         if let Some(user_id) = self.principal_to_user_id_map.remove(&old_principal) {
             self.principal_to_user_id_map.insert(new_principal, user_id);
@@ -360,7 +356,7 @@ impl CommunityMembers {
     pub fn set_display_name(&mut self, user_id: UserId, display_name: Option<String>, now: TimestampMillis) {
         if let Some(member) = self.members.get_mut(&user_id) {
             member.display_name = Timestamped::new(display_name, now);
-            self.display_names_last_updated = now;
+            self.updates.insert((now, user_id, MemberUpdate::DisplayNameChanged));
         }
     }
 
@@ -395,7 +391,6 @@ impl CommunityMembers {
     pub fn last_updated(&self) -> TimestampMillis {
         [
             self.user_groups_last_updated(),
-            self.display_names_last_updated(),
             self.updates.iter().next_back().map_or(0, |(ts, _, _)| *ts),
         ]
         .into_iter()
@@ -552,4 +547,5 @@ impl From<&CommunityMemberInternal> for CommunityMember {
 pub enum MemberUpdate {
     Lapsed = 1,
     Unlapsed = 2,
+    DisplayNameChanged = 3,
 }

backend/canisters/community/impl/src/queries/selected_updates.rs

@@ -115,18 +115,12 @@ fn selected_updates_impl(args: Args, state: &RuntimeState) -> Response {
 
     for (user_id, update) in state.data.members.iter_latest_updates(args.updates_since) {
         match update {
-            MemberUpdate::Lapsed | MemberUpdate::Unlapsed => {
+            MemberUpdate::Lapsed | MemberUpdate::Unlapsed | MemberUpdate::DisplayNameChanged => {
                 user_updates_handler.mark_member_updated(&mut result, user_id, false, false);
             }
         }
     }
 
-    for member in data.members.iter() {
-        if member.display_name().timestamp > args.updates_since {
-            user_updates_handler.mark_member_updated(&mut result, member.user_id, false, false);
-        }
-    }
-
     Success(result)
 }