perf(llc): Reduce the number of DB reads in ChatPersistenceClient.getChannelStates() (#2664)

VelikovPetar · web-flow · commit 508c0199b5e9 · 2026-05-22T17:55:22.000+02:00
* Rename legacy 'Moor' references to 'Drift'.

* Optimize getChannelStates by enriching only the relevant page.

* Update CHANGELOG.md.

* refactor(dao): Add tests

* refactor(dao): Update pagination

* refactor(dao): Remove unused method

* refactor(dao): Add MemberDao missing tests
diff --git a/packages/stream_chat_persistence/CHANGELOG.md b/packages/stream_chat_persistence/CHANGELOG.md
@@ -1,3 +1,9 @@
+# Upcoming
+
+🚀 Performance
+
+- Reduce the number of DB reads in the `ChatPersistenceClient.getChannelStates` method.
+
 ## 9.24.0
 
 - Updated `stream_chat` dependency to [`9.24.0`](https://pub.dev/packages/stream_chat/changelog).
diff --git a/packages/stream_chat_persistence/README.md b/packages/stream_chat_persistence/README.md
@@ -16,7 +16,7 @@
 - [Flutter Offline Docs](https://getstream.io/chat/docs/flutter-dart/flutter_offline/)
 
 This package provides a persistence client for fetching and saving chat data locally.
-Stream Chat Persistence uses [Moor](https://github.com/simolus3/moor) as a disk cache.
+Stream Chat Persistence uses [Drift](https://github.com/simolus3/drift) as a disk cache.
 
 ### Changelog
 
@@ -52,7 +52,7 @@ And you are ready to go...
 
 ## Flutter Web
 
-Due to Moor web (for offline storage) you need to include the sql.js library:
+Due to Drift web (for offline storage) you need to include the sql.js library:
 
 ```html
 <!doctype html>
diff --git a/packages/stream_chat_persistence/lib/src/dao/member_dao.dart b/packages/stream_chat_persistence/lib/src/dao/member_dao.dart
@@ -27,6 +27,34 @@ class MemberDao extends DatabaseAccessor<DriftChatDatabase>
         return memberEntity.toMember(user: userEntity.toUser());
       }).get();
 
+  /// Returns the membership row for [userId] in each channel listed in [cids],
+  /// keyed by `channelCid`.
+  ///
+  /// Channels in [cids] without a membership row for [userId] are absent from
+  /// the result. Executes a single `WHERE channel_cid IN (...) AND user_id = ?`
+  /// query.
+  Future<Map<String, Member>> getMembershipsForChannels(
+    List<String> cids,
+    String userId,
+  ) async {
+    if (cids.isEmpty) return const {};
+
+    final rows = await (select(members).join([
+      leftOuterJoin(users, members.userId.equalsExp(users.id)),
+    ])
+          ..where(
+            members.channelCid.isIn(cids) & members.userId.equals(userId),
+          ))
+        .get();
+
+    return {
+      for (final row in rows)
+        row.readTable(members).channelCid: row.readTable(members).toMember(
+              user: row.readTableOrNull(users)?.toUser(),
+            ),
+    };
+  }
+
   /// Updates all the members using the new [memberList] data
   Future<void> updateMembers(String cid, List<Member> memberList) =>
       bulkUpdateMembers({cid: memberList});
diff --git a/packages/stream_chat_persistence/lib/src/db/drift_chat_database.dart b/packages/stream_chat_persistence/lib/src/db/drift_chat_database.dart
@@ -8,7 +8,7 @@ export 'shared/shared_db.dart';
 
 part 'drift_chat_database.g.dart';
 
-/// A chat database implemented using moor
+/// A chat database implemented using drift
 @DriftDatabase(
   tables: [
     Channels,
diff --git a/packages/stream_chat_persistence/lib/src/db/shared/native_db.dart b/packages/stream_chat_persistence/lib/src/db/shared/native_db.dart
@@ -26,7 +26,7 @@ class SharedDB {
       return DriftChatDatabase(
         userId,
         DatabaseConnection.delayed(Future(() async {
-          final isolate = await _createMoorIsolate(
+          final isolate = await _createDriftIsolate(
             dbName,
             logStatements: logStatements,
           );
@@ -68,13 +68,13 @@ class SharedDB {
           File(request.targetPath),
           logStatements: request.logStatements,
         ));
-    final moorIsolate = DriftIsolate.inCurrent(
+    final driftIsolate = DriftIsolate.inCurrent(
       () => DatabaseConnection(executor),
     );
-    request.sendMoorIsolate.send(moorIsolate);
+    request.sendDriftIsolate.send(driftIsolate);
   }
 
-  static Future<DriftIsolate> _createMoorIsolate(
+  static Future<DriftIsolate> _createDriftIsolate(
     String dbName, {
     bool logStatements = false,
   }) async {
@@ -97,12 +97,12 @@ class SharedDB {
 
 class _IsolateStartRequest {
   const _IsolateStartRequest(
-    this.sendMoorIsolate,
+    this.sendDriftIsolate,
     this.targetPath, {
     this.logStatements = false,
   });
 
-  final SendPort sendMoorIsolate;
+  final SendPort sendDriftIsolate;
   final String targetPath;
   final bool logStatements;
 }
diff --git a/packages/stream_chat_persistence/lib/src/entity/channel_queries.dart b/packages/stream_chat_persistence/lib/src/entity/channel_queries.dart
@@ -1,7 +1,7 @@
 // coverage:ignore-file
 import 'package:drift/drift.dart';
 
-/// Represents a [ChannelQueries] table in [MoorChatDatabase].
+/// Represents a [ChannelQueries] table in [DriftChatDatabase].
 @DataClassName('ChannelQueryEntity')
 class ChannelQueries extends Table {
   /// The unique hash of this query
diff --git a/packages/stream_chat_persistence/lib/src/entity/channels.dart b/packages/stream_chat_persistence/lib/src/entity/channels.dart
@@ -2,7 +2,7 @@
 import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/converter/converter.dart';
 
-/// Represents a [Channels] table in [MoorChatDatabase].
+/// Represents a [Channels] table in [DriftChatDatabase].
 @DataClassName('ChannelEntity')
 class Channels extends Table {
   /// The id of this channel
diff --git a/packages/stream_chat_persistence/lib/src/entity/connection_events.dart b/packages/stream_chat_persistence/lib/src/entity/connection_events.dart
@@ -2,7 +2,7 @@
 import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/converter/map_converter.dart';
 
-/// Represents a [ConnectionEvents] table in [MoorChatDatabase].
+/// Represents a [ConnectionEvents] table in [DriftChatDatabase].
 @DataClassName('ConnectionEventEntity')
 class ConnectionEvents extends Table {
   /// event id
diff --git a/packages/stream_chat_persistence/lib/src/entity/draft_messages.dart b/packages/stream_chat_persistence/lib/src/entity/draft_messages.dart
@@ -4,7 +4,7 @@ import 'package:stream_chat_persistence/src/converter/converter.dart';
 import 'package:stream_chat_persistence/src/entity/channels.dart';
 import 'package:stream_chat_persistence/src/entity/messages.dart';
 
-/// Represents a [DraftMessages] table in [MoorChatDatabase].
+/// Represents a [DraftMessages] table in [DriftChatDatabase].
 @DataClassName('DraftMessageEntity')
 class DraftMessages extends Table {
   /// The message id
diff --git a/packages/stream_chat_persistence/lib/src/entity/members.dart b/packages/stream_chat_persistence/lib/src/entity/members.dart
@@ -3,7 +3,7 @@ import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/converter/map_converter.dart';
 import 'package:stream_chat_persistence/src/entity/channels.dart';
 
-/// Represents a [Members] table in [MoorChatDatabase].
+/// Represents a [Members] table in [DriftChatDatabase].
 @DataClassName('MemberEntity')
 class Members extends Table {
   /// The interested user id
diff --git a/packages/stream_chat_persistence/lib/src/entity/messages.dart b/packages/stream_chat_persistence/lib/src/entity/messages.dart
@@ -5,7 +5,7 @@ import 'package:stream_chat_persistence/src/converter/map_converter.dart';
 import 'package:stream_chat_persistence/src/converter/reaction_groups_converter.dart';
 import 'package:stream_chat_persistence/src/entity/channels.dart';
 
-/// Represents a [Messages] table in [MoorChatDatabase].
+/// Represents a [Messages] table in [DriftChatDatabase].
 @DataClassName('MessageEntity')
 class Messages extends Table {
   /// The message id
diff --git a/packages/stream_chat_persistence/lib/src/entity/pinned_message_reactions.dart b/packages/stream_chat_persistence/lib/src/entity/pinned_message_reactions.dart
@@ -3,7 +3,7 @@ import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/entity/pinned_messages.dart';
 import 'package:stream_chat_persistence/src/entity/reactions.dart';
 
-/// Represents a [PinnedMessageReactions] table in [MoorChatDatabase].
+/// Represents a [PinnedMessageReactions] table in [DriftChatDatabase].
 @DataClassName('PinnedMessageReactionEntity')
 class PinnedMessageReactions extends Reactions {
   /// The messageId to which the reaction belongs
diff --git a/packages/stream_chat_persistence/lib/src/entity/pinned_messages.dart b/packages/stream_chat_persistence/lib/src/entity/pinned_messages.dart
@@ -2,6 +2,6 @@
 import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/entity/messages.dart';
 
-/// Represents a [PinnedMessages] table in [MoorChatDatabase].
+/// Represents a [PinnedMessages] table in [DriftChatDatabase].
 @DataClassName('PinnedMessageEntity')
 class PinnedMessages extends Messages {}
diff --git a/packages/stream_chat_persistence/lib/src/entity/poll_votes.dart b/packages/stream_chat_persistence/lib/src/entity/poll_votes.dart
@@ -2,7 +2,7 @@
 import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/entity/entity.dart';
 
-/// Represents a [PollVotes] table in [MoorChatDatabase].
+/// Represents a [PollVotes] table in [DriftChatDatabase].
 @DataClassName('PollVoteEntity')
 class PollVotes extends Table {
   /// The unique identifier of the poll vote.
diff --git a/packages/stream_chat_persistence/lib/src/entity/polls.dart b/packages/stream_chat_persistence/lib/src/entity/polls.dart
@@ -4,7 +4,7 @@ import 'package:stream_chat_persistence/src/converter/list_converter.dart';
 import 'package:stream_chat_persistence/src/converter/map_converter.dart';
 import 'package:stream_chat_persistence/src/converter/voting_visibility_converter.dart';
 
-/// Represents a [Polls] table in [MoorChatDatabase].
+/// Represents a [Polls] table in [DriftChatDatabase].
 @DataClassName('PollEntity')
 class Polls extends Table {
   /// The unique identifier of the poll.
diff --git a/packages/stream_chat_persistence/lib/src/entity/reactions.dart b/packages/stream_chat_persistence/lib/src/entity/reactions.dart
@@ -3,7 +3,7 @@ import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/converter/map_converter.dart';
 import 'package:stream_chat_persistence/src/entity/messages.dart';
 
-/// Represents a [Reactions] table in [MoorChatDatabase].
+/// Represents a [Reactions] table in [DriftChatDatabase].
 @DataClassName('ReactionEntity')
 class Reactions extends Table {
   /// The id of the user that sent the reaction
diff --git a/packages/stream_chat_persistence/lib/src/entity/reads.dart b/packages/stream_chat_persistence/lib/src/entity/reads.dart
@@ -2,7 +2,7 @@
 import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/entity/channels.dart';
 
-/// Represents a [Reads] table in [MoorChatDatabase].
+/// Represents a [Reads] table in [DriftChatDatabase].
 @DataClassName('ReadEntity')
 class Reads extends Table {
   /// Date of the read event
diff --git a/packages/stream_chat_persistence/lib/src/entity/users.dart b/packages/stream_chat_persistence/lib/src/entity/users.dart
@@ -2,7 +2,7 @@
 import 'package:drift/drift.dart';
 import 'package:stream_chat_persistence/src/converter/map_converter.dart';
 
-/// Represents a [Users] table in [MoorChatDatabase].
+/// Represents a [Users] table in [DriftChatDatabase].
 @DataClassName('UserEntity')
 class Users extends Table {
   /// User id
diff --git a/packages/stream_chat_persistence/lib/src/stream_chat_persistence_client.dart b/packages/stream_chat_persistence/lib/src/stream_chat_persistence_client.dart
@@ -270,29 +270,36 @@ class StreamChatPersistenceClient extends ChatPersistenceClient {
     assert(_debugIsConnected, '');
     _logger.info('getChannelStates');
 
-    final channels = await db!.channelQueryDao.getChannels(filter: filter);
-
-    final channelStates = await Future.wait(
-      channels.map((e) => getChannelStateByCid(e.cid)),
-    );
-
-    // Sort the channel states
-    if (channelStateSort != null && channelStateSort.isNotEmpty) {
-      channelStates.sort(channelStateSort.compare);
+    // 1) Lightweight load — channel rows + createdBy user only.
+    final channelModels = await db!.channelQueryDao.getChannels(filter: filter);
+
+    // 2) Wrap each model in a sort envelope. No state loaded yet.
+    var envelopes = channelModels
+        .map((m) => ChannelState(channel: m))
+        .toList(growable: false);
+
+    // 3) If sort uses `pinnedAt`, preload the current user's memberships in
+    //    one batched query and attach them to the envelopes.
+    final clientUserId = userId;
+    if (clientUserId != null && _sortRequiresMembership(channelStateSort)) {
+      envelopes = await _attachMemberships(envelopes, clientUserId);
     }
 
-    // Apply offset
-    if (paginationParams?.offset case final paginationOffset?) {
-      final clampedOffset = paginationOffset.clamp(0, channelStates.length);
-      channelStates.removeRange(0, clampedOffset);
+    // 4) Sort using the existing comparator — same logic as today, just on
+    //    envelopes instead of fully-hydrated states.
+    if (channelStateSort != null && channelStateSort.isNotEmpty) {
+      envelopes.sort(channelStateSort.compare);
     }
 
-    // Apply limit
-    if (paginationParams?.limit case final paginationLimit?) {
-      return channelStates.take(paginationLimit).toList();
-    }
+    // 5) Slice the page.
+    final total = envelopes.length;
+    final offset = (paginationParams?.offset ?? 0).clamp(0, total);
+    final limit = paginationParams?.limit ?? (total - offset);
+    final pagedCids =
+        envelopes.skip(offset).take(limit).map((s) => s.channel!.cid).toList();
 
-    return channelStates;
+    // 6) Hydrate ONLY the page.
+    return Future.wait(pagedCids.map(getChannelStateByCid));
   }
 
   @override
@@ -481,4 +488,25 @@ class StreamChatPersistenceClient extends ChatPersistenceClient {
       db = null;
     }
   }
+
+  bool _sortRequiresMembership(SortOrder<ChannelState>? sort) =>
+      sort?.any((opt) => opt.field == ChannelSortKey.pinnedAt) ?? false;
+
+  Future<List<ChannelState>> _attachMemberships(
+    List<ChannelState> envelopes,
+    String currentUserId,
+  ) async {
+    final cids = envelopes
+        .map((s) => s.channel?.cid)
+        .whereType<String>()
+        .toList(growable: false);
+    final memberships = await db!.memberDao.getMembershipsForChannels(
+      cids,
+      currentUserId,
+    );
+    return [
+      for (final s in envelopes)
+        s.copyWith(membership: memberships[s.channel?.cid]),
+    ];
+  }
 }
diff --git a/packages/stream_chat_persistence/test/src/dao/member_dao_test.dart b/packages/stream_chat_persistence/test/src/dao/member_dao_test.dart
@@ -77,6 +77,59 @@ void main() {
     }
   });
 
+  test('getMembershipsForChannels', () async {
+    const cid1 = 'test:Cid1';
+    const cid2 = 'test:Cid2';
+    const cid3 = 'test:Cid3';
+    const targetUserId = 'targetUserId';
+
+    // Should be empty when cids list is empty
+    final emptyResult = await memberDao.getMembershipsForChannels(
+      [],
+      targetUserId,
+    );
+    expect(emptyResult, isEmpty);
+
+    // Should be empty when there is no data
+    final noDataResult = await memberDao.getMembershipsForChannels(
+      [cid1, cid2, cid3],
+      targetUserId,
+    );
+    expect(noDataResult, isEmpty);
+
+    // Preparing test data: target user is a member of cid1 and cid2,
+    // but not cid3.
+    final targetUser = User(id: targetUserId);
+    final otherUser = User(id: 'otherUserId');
+    Member memberFor(User user) => Member(
+          user: user,
+          createdAt: DateTime.now(),
+          updatedAt: DateTime.now(),
+        );
+    await database.userDao.updateUsers([targetUser, otherUser]);
+    await database.channelDao.updateChannels([
+      ChannelModel(cid: cid1),
+      ChannelModel(cid: cid2),
+      ChannelModel(cid: cid3),
+    ]);
+    await memberDao.updateMembers(cid1, [memberFor(targetUser)]);
+    await memberDao.updateMembers(cid2, [memberFor(targetUser)]);
+    await memberDao.updateMembers(cid3, [memberFor(otherUser)]);
+
+    // Should return memberships only for channels where target user
+    // is a member, keyed by channelCid.
+    final memberships = await memberDao.getMembershipsForChannels(
+      [cid1, cid2, cid3],
+      targetUserId,
+    );
+    expect(memberships.length, 2);
+    expect(memberships.keys, containsAll([cid1, cid2]));
+    expect(memberships.containsKey(cid3), isFalse);
+
+    expect(memberships[cid1]!.user!.id, targetUserId);
+    expect(memberships[cid2]!.user!.id, targetUserId);
+  });
+
   test('updateMembers', () async {
     const cid = 'test:Cid';
 
diff --git a/packages/stream_chat_persistence/test/src/db/drift_chat_database_test.dart b/packages/stream_chat_persistence/test/src/db/drift_chat_database_test.dart
@@ -9,7 +9,7 @@ DatabaseConnection _backgroundConnection() =>
 
 void main() {
   test(
-    'default constructor should create a new instance of MoorChatDatabase',
+    'default constructor should create a new instance of DriftChatDatabase',
     () async {
       const userId = 'testUserId';
       final executor = NativeDatabase.memory();
@@ -24,7 +24,7 @@ void main() {
   );
 
   test(
-    'connect constructor should create a new instance of MoorChatDatabase',
+    'connect constructor should create a new instance of DriftChatDatabase',
     () async {
       const userId = 'testUserId';
       final isolate = await DriftIsolate.spawn(_backgroundConnection);
diff --git a/packages/stream_chat_persistence/test/stream_chat_persistence_client_test.dart b/packages/stream_chat_persistence/test/stream_chat_persistence_client_test.dart
