perf(llc): Reduce the number of read message per channel from DB when paginating (part 2)

packages/stream_chat_persistence/CHANGELOG.md

@@ -1,8 +1,19 @@
-# Upcoming
+## Upcoming Changes
 
 🚀 Performance
 
 - Reduce the number of DB reads in the `ChatPersistenceClient.getChannelStates` method.
+- Read only the messages matching the `PaginationParams` from DB when calling `MessageDao.getMessagesByCid` instead of reading all messages for the channel and applying pagination in memory.
+- Read only the reactions matching the `userId` from DB when calling `ReactionDao.getReactionsByUserId` instead of reading all reactions for the message and filtering in memory.
+- Read only the reactions matching the `userId` from DB when calling `PinnedMessageReactionDao.getReactionsByUserId` instead of reading all reactions for the message and filtering in memory.
+- Improve the message read times from DB.
+
+🐞 Fixed
+
+- `MessageDao.getMessagesByCid` now honours `PaginationParams.lessThanOrEqual` and `PaginationParams.greaterThanOrEqual` (inclusive of the cursor message), in addition to the existing strict `lessThan`/`greaterThan`.
+- `MessageDao.getMessagesByCid` now treats `PaginationParams.greaterThan` as strict (exclusive of the cursor), matching the `PaginationParams` contract and the existing `lessThan` behaviour.
+- `MessageDao.getMessagesByCid` with a forward cursor (`greaterThan`/`greaterThanOrEqual`) and a `limit` now returns the messages immediately AFTER the pivot, instead of the channel tail — mirroring how `lessThan` already returned the messages immediately before the pivot.
+
 
 ## 9.24.0
 

packages/stream_chat_persistence/lib/src/dao/draft_message_dao.dart

@@ -3,6 +3,7 @@
 import 'package:drift/drift.dart';
 import 'package:stream_chat/stream_chat.dart';
 import 'package:stream_chat_persistence/src/db/drift_chat_database.dart';
+import 'package:stream_chat_persistence/src/db/query_utils.dart';
 import 'package:stream_chat_persistence/src/entity/entity.dart';
 import 'package:stream_chat_persistence/src/mapper/mapper.dart';
 
@@ -66,6 +67,27 @@ class DraftMessageDao extends DatabaseAccessor<DriftChatDatabase>
     return _draftFromEntity(result);
   }
 
+  /// Returns thread drafts in [cid] for every parent message id in
+  /// [parentIds], keyed by parent message id.
+  Future<Map<String, Draft?>> getDraftMessagesByParentIds(
+    String cid,
+    List<String> parentIds,
+  ) async {
+    if (parentIds.isEmpty) return const {};
+    final result = <String, Draft?>{for (final id in parentIds) id: null};
+    for (final chunk in chunked(parentIds)) {
+      final query = select(draftMessages)
+        ..where((tbl) => tbl.channelCid.equals(cid) & tbl.parentId.isIn(chunk));
+      final entities = await query.get();
+      for (final entity in entities) {
+        if (entity.parentId case final pid?) {
+          result[pid] = await _draftFromEntity(entity);
+        }
+      }
+    }
+    return result;
+  }
+
   /// Updates the draft message data of a particular channel with
   /// the new [messageList] data.
   Future<void> updateDraftMessages(List<Draft> draftMessageList) {