Misskey® Reactions Buffering Technology™ (#14579)

* wip

* wip

* Update ReactionsBufferingService.ts

* Update ReactionsBufferingService.ts

* wip

* wip

* wip

* Update ReactionsBufferingService.ts

* wip

* wip

* wip

* Update NoteEntityService.ts

* wip

* wip

* wip

* wip

* Update CHANGELOG.md

5 files changed, 275 insertions, 39 deletions

diff --git a/packages/backend/src/core/CoreModule.ts b/packages/backend/src/core/CoreModule.ts
index 674241ac12..3b3c35f976 100644
--- a/packages/backend/src/core/CoreModule.ts
+++ b/packages/backend/src/core/CoreModule.ts
@@ -50,6 +50,7 @@ import { PollService } from './PollService.js';
 import { PushNotificationService } from './PushNotificationService.js';
 import { QueryService } from './QueryService.js';
 import { ReactionService } from './ReactionService.js';
+import { ReactionsBufferingService } from './ReactionsBufferingService.js';
 import { RelayService } from './RelayService.js';
 import { RoleService } from './RoleService.js';
 import { S3Service } from './S3Service.js';
@@ -193,6 +194,7 @@ const $ProxyAccountService: Provider = { provide: 'ProxyAccountService', useExis
 const $PushNotificationService: Provider = { provide: 'PushNotificationService', useExisting: PushNotificationService };
 const $QueryService: Provider = { provide: 'QueryService', useExisting: QueryService };
 const $ReactionService: Provider = { provide: 'ReactionService', useExisting: ReactionService };
+const $ReactionsBufferingService: Provider = { provide: 'ReactionsBufferingService', useExisting: ReactionsBufferingService };
 const $RelayService: Provider = { provide: 'RelayService', useExisting: RelayService };
 const $RoleService: Provider = { provide: 'RoleService', useExisting: RoleService };
 const $S3Service: Provider = { provide: 'S3Service', useExisting: S3Service };
@@ -342,6 +344,7 @@ const $ApQuestionService: Provider = { provide: 'ApQuestionService', useExisting
 		PushNotificationService,
 		QueryService,
 		ReactionService,
+		ReactionsBufferingService,
 		RelayService,
 		RoleService,
 		S3Service,
@@ -487,6 +490,7 @@ const $ApQuestionService: Provider = { provide: 'ApQuestionService', useExisting
 		$PushNotificationService,
 		$QueryService,
 		$ReactionService,
+		$ReactionsBufferingService,
 		$RelayService,
 		$RoleService,
 		$S3Service,
@@ -633,6 +637,7 @@ const $ApQuestionService: Provider = { provide: 'ApQuestionService', useExisting
 		PushNotificationService,
 		QueryService,
 		ReactionService,
+		ReactionsBufferingService,
 		RelayService,
 		RoleService,
 		S3Service,
@@ -777,6 +782,7 @@ const $ApQuestionService: Provider = { provide: 'ApQuestionService', useExisting
 		$PushNotificationService,
 		$QueryService,
 		$ReactionService,
+		$ReactionsBufferingService,
 		$RelayService,
 		$RoleService,
 		$S3Service,
diff --git a/packages/backend/src/core/QueueService.ts b/packages/backend/src/core/QueueService.ts
index ddb90a051f..f35e456556 100644
--- a/packages/backend/src/core/QueueService.ts
+++ b/packages/backend/src/core/QueueService.ts
@@ -87,6 +87,12 @@ export class QueueService {
 			repeat: { pattern: '*/5 * * * *' },
 			removeOnComplete: true,
 		});
+
+		this.systemQueue.add('bakeBufferedReactions', {
+		}, {
+			repeat: { pattern: '0 0 * * *' },
+			removeOnComplete: true,
+		});
 	}
 
 	@bindThis
diff --git a/packages/backend/src/core/ReactionService.ts b/packages/backend/src/core/ReactionService.ts
index 371207c33a..5993c42a1f 100644
--- a/packages/backend/src/core/ReactionService.ts
+++ b/packages/backend/src/core/ReactionService.ts
@@ -4,7 +4,6 @@
  */
 
 import { Inject, Injectable } from '@nestjs/common';
-import * as Redis from 'ioredis';
 import { DI } from '@/di-symbols.js';
 import type { EmojisRepository, NoteReactionsRepository, UsersRepository, NotesRepository } from '@/models/_.js';
 import { IdentifiableError } from '@/misc/identifiable-error.js';
@@ -30,9 +29,10 @@ import { RoleService } from '@/core/RoleService.js';
 import { FeaturedService } from '@/core/FeaturedService.js';
 import { trackPromise } from '@/misc/promise-tracker.js';
 import { isQuote, isRenote } from '@/misc/is-renote.js';
+import { ReactionsBufferingService } from '@/core/ReactionsBufferingService.js';
+import { PER_NOTE_REACTION_USER_PAIR_CACHE_MAX } from '@/const.js';
 
 const FALLBACK = '\u2764';
-const PER_NOTE_REACTION_USER_PAIR_CACHE_MAX = 16;
 
 const legacies: Record<string, string> = {
 	'like': '👍',
@@ -71,9 +71,6 @@ const decodeCustomEmojiRegexp = /^:([\w+-]+)(?:@([\w.-]+))?:$/;
 @Injectable()
 export class ReactionService {
 	constructor(
-		@Inject(DI.redis)
-		private redisClient: Redis.Redis,
-
 		@Inject(DI.usersRepository)
 		private usersRepository: UsersRepository,
 
@@ -93,6 +90,7 @@ export class ReactionService {
 		private userEntityService: UserEntityService,
 		private noteEntityService: NoteEntityService,
 		private userBlockingService: UserBlockingService,
+		private reactionsBufferingService: ReactionsBufferingService,
 		private idService: IdService,
 		private featuredService: FeaturedService,
 		private globalEventService: GlobalEventService,
@@ -174,7 +172,6 @@ export class ReactionService {
 			reaction,
 		};
 
-		// Create reaction
 		try {
 			await this.noteReactionsRepository.insert(record);
 		} catch (e) {
@@ -198,16 +195,25 @@ export class ReactionService {
 		}
 
 		// Increment reactions count
-		const sql = `jsonb_set("reactions", '{${reaction}}', (COALESCE("reactions"->>'${reaction}', '0')::int + 1)::text::jsonb)`;
-		await this.notesRepository.createQueryBuilder().update()
-			.set({
-				reactions: () => sql,
-				...(note.reactionAndUserPairCache.length < PER_NOTE_REACTION_USER_PAIR_CACHE_MAX ? {
-					reactionAndUserPairCache: () => `array_append("reactionAndUserPairCache", '${user.id}/${reaction}')`,
-				} : {}),
-			})
-			.where('id = :id', { id: note.id })
-			.execute();
+		if (meta.enableReactionsBuffering) {
+			await this.reactionsBufferingService.create(note.id, user.id, reaction, note.reactionAndUserPairCache);
+
+			// for debugging
+			if (reaction === ':angry_ai:') {
+				this.reactionsBufferingService.bake();
+			}
+		} else {
+			const sql = `jsonb_set("reactions", '{${reaction}}', (COALESCE("reactions"->>'${reaction}', '0')::int + 1)::text::jsonb)`;
+			await this.notesRepository.createQueryBuilder().update()
+				.set({
+					reactions: () => sql,
+					...(note.reactionAndUserPairCache.length < PER_NOTE_REACTION_USER_PAIR_CACHE_MAX ? {
+						reactionAndUserPairCache: () => `array_append("reactionAndUserPairCache", '${user.id}/${reaction}')`,
+					} : {}),
+				})
+				.where('id = :id', { id: note.id })
+				.execute();
+		}
 
 		// 30%の確率、セルフではない、3日以内に投稿されたノートの場合ハイライト用ランキング更新
 		if (
@@ -304,15 +310,21 @@ export class ReactionService {
 			throw new IdentifiableError('60527ec9-b4cb-4a88-a6bd-32d3ad26817d', 'not reacted');
 		}
 
+		const meta = await this.metaService.fetch();
+
 		// Decrement reactions count
-		const sql = `jsonb_set("reactions", '{${exist.reaction}}', (COALESCE("reactions"->>'${exist.reaction}', '0')::int - 1)::text::jsonb)`;
-		await this.notesRepository.createQueryBuilder().update()
-			.set({
-				reactions: () => sql,
-				reactionAndUserPairCache: () => `array_remove("reactionAndUserPairCache", '${user.id}/${exist.reaction}')`,
-			})
-			.where('id = :id', { id: note.id })
-			.execute();
+		if (meta.enableReactionsBuffering) {
+			await this.reactionsBufferingService.delete(note.id, user.id, exist.reaction);
+		} else {
+			const sql = `jsonb_set("reactions", '{${exist.reaction}}', (COALESCE("reactions"->>'${exist.reaction}', '0')::int - 1)::text::jsonb)`;
+			await this.notesRepository.createQueryBuilder().update()
+				.set({
+					reactions: () => sql,
+					reactionAndUserPairCache: () => `array_remove("reactionAndUserPairCache", '${user.id}/${exist.reaction}')`,
+				})
+				.where('id = :id', { id: note.id })
+				.execute();
+		}
 
 		this.globalEventService.publishNoteStream(note.id, 'unreacted', {
 			reaction: this.decodeReaction(exist.reaction).reaction,
diff --git a/packages/backend/src/core/ReactionsBufferingService.ts b/packages/backend/src/core/ReactionsBufferingService.ts
new file mode 100644
index 0000000000..b1a197feeb
--- /dev/null
+++ b/packages/backend/src/core/ReactionsBufferingService.ts
@@ -0,0 +1,162 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Inject, Injectable } from '@nestjs/common';
+import * as Redis from 'ioredis';
+import { DI } from '@/di-symbols.js';
+import type { MiNote } from '@/models/Note.js';
+import { bindThis } from '@/decorators.js';
+import type { MiUser, NotesRepository } from '@/models/_.js';
+import type { Config } from '@/config.js';
+import { PER_NOTE_REACTION_USER_PAIR_CACHE_MAX } from '@/const.js';
+
+const REDIS_DELTA_PREFIX = 'reactionsBufferDeltas';
+const REDIS_PAIR_PREFIX = 'reactionsBufferPairs';
+
+@Injectable()
+export class ReactionsBufferingService {
+	constructor(
+		@Inject(DI.config)
+		private config: Config,
+
+		@Inject(DI.redisForReactions)
+		private redisForReactions: Redis.Redis, // TODO: 専用のRedisインスタンスにする
+
+		@Inject(DI.notesRepository)
+		private notesRepository: NotesRepository,
+	) {
+	}
+
+	@bindThis
+	public async create(noteId: MiNote['id'], userId: MiUser['id'], reaction: string, currentPairs: string[]): Promise<void> {
+		const pipeline = this.redisForReactions.pipeline();
+		pipeline.hincrby(`${REDIS_DELTA_PREFIX}:${noteId}`, reaction, 1);
+		for (let i = 0; i < currentPairs.length; i++) {
+			pipeline.zadd(`${REDIS_PAIR_PREFIX}:${noteId}`, i, currentPairs[i]);
+		}
+		pipeline.zadd(`${REDIS_PAIR_PREFIX}:${noteId}`, Date.now(), `${userId}/${reaction}`);
+		pipeline.zremrangebyrank(`${REDIS_PAIR_PREFIX}:${noteId}`, 0, -(PER_NOTE_REACTION_USER_PAIR_CACHE_MAX + 1));
+		await pipeline.exec();
+	}
+
+	@bindThis
+	public async delete(noteId: MiNote['id'], userId: MiUser['id'], reaction: string): Promise<void> {
+		const pipeline = this.redisForReactions.pipeline();
+		pipeline.hincrby(`${REDIS_DELTA_PREFIX}:${noteId}`, reaction, -1);
+		pipeline.zrem(`${REDIS_PAIR_PREFIX}:${noteId}`, `${userId}/${reaction}`);
+		// TODO: 「消した要素一覧」も持っておかないとcreateされた時に上書きされて復活する
+		await pipeline.exec();
+	}
+
+	@bindThis
+	public async get(noteId: MiNote['id']): Promise<{
+		deltas: Record<string, number>;
+		pairs: ([MiUser['id'], string])[];
+	}> {
+		const pipeline = this.redisForReactions.pipeline();
+		pipeline.hgetall(`${REDIS_DELTA_PREFIX}:${noteId}`);
+		pipeline.zrange(`${REDIS_PAIR_PREFIX}:${noteId}`, 0, -1);
+		const results = await pipeline.exec();
+
+		const resultDeltas = results![0][1] as Record<string, string>;
+		const resultPairs = results![1][1] as string[];
+
+		const deltas = {} as Record<string, number>;
+		for (const [name, count] of Object.entries(resultDeltas)) {
+			deltas[name] = parseInt(count);
+		}
+
+		const pairs = resultPairs.map(x => x.split('/') as [MiUser['id'], string]);
+
+		return {
+			deltas,
+			pairs,
+		};
+	}
+
+	@bindThis
+	public async getMany(noteIds: MiNote['id'][]): Promise<Map<MiNote['id'], {
+		deltas: Record<string, number>;
+		pairs: ([MiUser['id'], string])[];
+	}>> {
+		const map = new Map<MiNote['id'], {
+			deltas: Record<string, number>;
+			pairs: ([MiUser['id'], string])[];
+		}>();
+
+		const pipeline = this.redisForReactions.pipeline();
+		for (const noteId of noteIds) {
+			pipeline.hgetall(`${REDIS_DELTA_PREFIX}:${noteId}`);
+			pipeline.zrange(`${REDIS_PAIR_PREFIX}:${noteId}`, 0, -1);
+		}
+		const results = await pipeline.exec();
+
+		const opsForEachNotes = 2;
+		for (let i = 0; i < noteIds.length; i++) {
+			const noteId = noteIds[i];
+			const resultDeltas = results![i * opsForEachNotes][1] as Record<string, string>;
+			const resultPairs = results![i * opsForEachNotes + 1][1] as string[];
+
+			const deltas = {} as Record<string, number>;
+			for (const [name, count] of Object.entries(resultDeltas)) {
+				deltas[name] = parseInt(count);
+			}
+
+			const pairs = resultPairs.map(x => x.split('/') as [MiUser['id'], string]);
+
+			map.set(noteId, {
+				deltas,
+				pairs,
+			});
+		}
+
+		return map;
+	}
+
+	// TODO: scanは重い可能性があるので、別途 bufferedNoteIds を直接Redis上に持っておいてもいいかもしれない
+	@bindThis
+	public async bake(): Promise<void> {
+		const bufferedNoteIds = [];
+		let cursor = '0';
+		do {
+			// https://github.com/redis/ioredis#transparent-key-prefixing
+			const result = await this.redisForReactions.scan(
+				cursor,
+				'MATCH',
+				`${this.config.redis.prefix}:${REDIS_DELTA_PREFIX}:*`,
+				'COUNT',
+				'1000');
+
+			cursor = result[0];
+			bufferedNoteIds.push(...result[1].map(x => x.replace(`${this.config.redis.prefix}:${REDIS_DELTA_PREFIX}:`, '')));
+		} while (cursor !== '0');
+
+		const bufferedMap = await this.getMany(bufferedNoteIds);
+
+		// clear
+		const pipeline = this.redisForReactions.pipeline();
+		for (const noteId of bufferedNoteIds) {
+			pipeline.del(`${REDIS_DELTA_PREFIX}:${noteId}`);
+			pipeline.del(`${REDIS_PAIR_PREFIX}:${noteId}`);
+		}
+		await pipeline.exec();
+
+		// TODO: SQL一個にまとめたい
+		for (const [noteId, buffered] of bufferedMap) {
+			const sql = Object.entries(buffered.deltas)
+				.map(([reaction, count]) =>
+					`jsonb_set("reactions", '{${reaction}}', (COALESCE("reactions"->>'${reaction}', '0')::int + ${count})::text::jsonb)`)
+				.join(' || ');
+
+			this.notesRepository.createQueryBuilder().update()
+				.set({
+					reactions: () => sql,
+					reactionAndUserPairCache: buffered.pairs.map(x => x.join('/')),
+				})
+				.where('id = :id', { id: noteId })
+				.execute();
+		}
+	}
+}
diff --git a/packages/backend/src/core/entities/NoteEntityService.ts b/packages/backend/src/core/entities/NoteEntityService.ts
index 2cd092231c..7506d804c3 100644
--- a/packages/backend/src/core/entities/NoteEntityService.ts
+++ b/packages/backend/src/core/entities/NoteEntityService.ts
@@ -11,24 +11,39 @@ import type { Packed } from '@/misc/json-schema.js';
 import { awaitAll } from '@/misc/prelude/await-all.js';
 import type { MiUser } from '@/models/User.js';
 import type { MiNote } from '@/models/Note.js';
-import type { MiNoteReaction } from '@/models/NoteReaction.js';
 import type { UsersRepository, NotesRepository, FollowingsRepository, PollsRepository, PollVotesRepository, NoteReactionsRepository, ChannelsRepository } from '@/models/_.js';
 import { bindThis } from '@/decorators.js';
 import { DebounceLoader } from '@/misc/loader.js';
 import { IdService } from '@/core/IdService.js';
+import { ReactionsBufferingService } from '@/core/ReactionsBufferingService.js';
+import { MetaService } from '@/core/MetaService.js';
 import type { OnModuleInit } from '@nestjs/common';
 import type { CustomEmojiService } from '../CustomEmojiService.js';
 import type { ReactionService } from '../ReactionService.js';
 import type { UserEntityService } from './UserEntityService.js';
 import type { DriveFileEntityService } from './DriveFileEntityService.js';
 
+function mergeReactions(src: Record<string, number>, delta: Record<string, number>) {
+	const reactions = { ...src };
+	for (const [name, count] of Object.entries(delta)) {
+		if (reactions[name] != null) {
+			reactions[name] += count;
+		} else {
+			reactions[name] = count;
+		}
+	}
+	return reactions;
+}
+
 @Injectable()
 export class NoteEntityService implements OnModuleInit {
 	private userEntityService: UserEntityService;
 	private driveFileEntityService: DriveFileEntityService;
 	private customEmojiService: CustomEmojiService;
 	private reactionService: ReactionService;
+	private reactionsBufferingService: ReactionsBufferingService;
 	private idService: IdService;
+	private metaService: MetaService;
 	private noteLoader = new DebounceLoader(this.findNoteOrFail);
 
 	constructor(
@@ -59,6 +74,9 @@ export class NoteEntityService implements OnModuleInit {
 		//private driveFileEntityService: DriveFileEntityService,
 		//private customEmojiService: CustomEmojiService,
 		//private reactionService: ReactionService,
+		//private reactionsBufferingService: ReactionsBufferingService,
+		//private idService: IdService,
+		//private metaService: MetaService,
 	) {
 	}
 
@@ -67,7 +85,9 @@ export class NoteEntityService implements OnModuleInit {
 		this.driveFileEntityService = this.moduleRef.get('DriveFileEntityService');
 		this.customEmojiService = this.moduleRef.get('CustomEmojiService');
 		this.reactionService = this.moduleRef.get('ReactionService');
+		this.reactionsBufferingService = this.moduleRef.get('ReactionsBufferingService');
 		this.idService = this.moduleRef.get('IdService');
+		this.metaService = this.moduleRef.get('MetaService');
 	}
 
 	@bindThis
@@ -287,6 +307,7 @@ export class NoteEntityService implements OnModuleInit {
 			skipHide?: boolean;
 			withReactionAndUserPairCache?: boolean;
 			_hint_?: {
+				bufferdReactions: Map<MiNote['id'], { deltas: Record<string, number>; pairs: ([MiUser['id'], string])[] }> | null;
 				myReactions: Map<MiNote['id'], string | null>;
 				packedFiles: Map<MiNote['fileIds'][number], Packed<'DriveFile'> | null>;
 				packedUsers: Map<MiUser['id'], Packed<'UserLite'>>
@@ -303,6 +324,16 @@ export class NoteEntityService implements OnModuleInit {
 		const note = typeof src === 'object' ? src : await this.noteLoader.load(src);
 		const host = note.userHost;
 
+		const bufferdReactions = opts._hint_?.bufferdReactions != null ? (opts._hint_.bufferdReactions.get(note.id) ?? { deltas: {}, pairs: [] }) : await this.reactionsBufferingService.get(note.id);
+		const reactions = mergeReactions(note.reactions, bufferdReactions.deltas ?? {});
+		for (const [name, count] of Object.entries(reactions)) {
+			if (count <= 0) {
+				delete reactions[name];
+			}
+		}
+
+		const reactionAndUserPairCache = note.reactionAndUserPairCache.concat(bufferdReactions.pairs.map(x => x.join('/')));
+
 		let text = note.text;
 
 		if (note.name && (note.url ?? note.uri)) {
@@ -315,7 +346,7 @@ export class NoteEntityService implements OnModuleInit {
 				: await this.channelsRepository.findOneBy({ id: note.channelId })
 			: null;
 
-		const reactionEmojiNames = Object.keys(note.reactions)
+		const reactionEmojiNames = Object.keys(reactions)
 			.filter(x => x.startsWith(':') && x.includes('@') && !x.includes('@.')) // リモートカスタム絵文字のみ
 			.map(x => this.reactionService.decodeReaction(x).reaction.replaceAll(':', ''));
 		const packedFiles = options?._hint_?.packedFiles;
@@ -334,10 +365,10 @@ export class NoteEntityService implements OnModuleInit {
 			visibleUserIds: note.visibility === 'specified' ? note.visibleUserIds : undefined,
 			renoteCount: note.renoteCount,
 			repliesCount: note.repliesCount,
-			reactionCount: Object.values(note.reactions).reduce((a, b) => a + b, 0),
-			reactions: this.reactionService.convertLegacyReactions(note.reactions),
+			reactionCount: Object.values(reactions).reduce((a, b) => a + b, 0),
+			reactions: reactions,
 			reactionEmojis: this.customEmojiService.populateEmojis(reactionEmojiNames, host),
-			reactionAndUserPairCache: opts.withReactionAndUserPairCache ? note.reactionAndUserPairCache : undefined,
+			reactionAndUserPairCache: opts.withReactionAndUserPairCache ? reactionAndUserPairCache : undefined,
 			emojis: host != null ? this.customEmojiService.populateEmojis(note.emojis, host) : undefined,
 			tags: note.tags.length > 0 ? note.tags : undefined,
 			fileIds: note.fileIds,
@@ -376,8 +407,12 @@ export class NoteEntityService implements OnModuleInit {
 
 				poll: note.hasPoll ? this.populatePoll(note, meId) : undefined,
 
-				...(meId && Object.keys(note.reactions).length > 0 ? {
-					myReaction: this.populateMyReaction(note, meId, options?._hint_),
+				...(meId && Object.keys(reactions).length > 0 ? {
+					myReaction: this.populateMyReaction({
+						id: note.id,
+						reactions: reactions,
+						reactionAndUserPairCache: reactionAndUserPairCache,
+					}, meId, options?._hint_),
 				} : {}),
 			} : {}),
 		});
@@ -400,6 +435,10 @@ export class NoteEntityService implements OnModuleInit {
 	) {
 		if (notes.length === 0) return [];
 
+		const meta = await this.metaService.fetch();
+
+		const bufferdReactions = meta.enableReactionsBuffering ? await this.reactionsBufferingService.getMany(notes.map(x => x.id)) : null;
+
 		const meId = me ? me.id : null;
 		const myReactionsMap = new Map<MiNote['id'], string | null>();
 		if (meId) {
@@ -410,23 +449,33 @@ export class NoteEntityService implements OnModuleInit {
 
 			for (const note of notes) {
 				if (note.renote && (note.text == null && note.fileIds.length === 0)) { // pure renote
-					const reactionsCount = Object.values(note.renote.reactions).reduce((a, b) => a + b, 0);
+					const reactionsCount = Object.values(mergeReactions(note.renote.reactions, bufferdReactions?.get(note.renote.id)?.deltas ?? {})).reduce((a, b) => a + b, 0);
 					if (reactionsCount === 0) {
 						myReactionsMap.set(note.renote.id, null);
-					} else if (reactionsCount <= note.renote.reactionAndUserPairCache.length) {
-						const pair = note.renote.reactionAndUserPairCache.find(p => p.startsWith(meId));
-						myReactionsMap.set(note.renote.id, pair ? pair.split('/')[1] : null);
+					} else if (reactionsCount <= note.renote.reactionAndUserPairCache.length + (bufferdReactions?.get(note.renote.id)?.pairs.length ?? 0)) {
+						const pairInBuffer = bufferdReactions?.get(note.renote.id)?.pairs.find(p => p[0] === meId);
+						if (pairInBuffer) {
+							myReactionsMap.set(note.renote.id, pairInBuffer[1]);
+						} else {
+							const pair = note.renote.reactionAndUserPairCache.find(p => p.startsWith(meId));
+							myReactionsMap.set(note.renote.id, pair ? pair.split('/')[1] : null);
+						}
 					} else {
 						idsNeedFetchMyReaction.add(note.renote.id);
 					}
 				} else {
 					if (note.id < oldId) {
-						const reactionsCount = Object.values(note.reactions).reduce((a, b) => a + b, 0);
+						const reactionsCount = Object.values(mergeReactions(note.reactions, bufferdReactions?.get(note.id)?.deltas ?? {})).reduce((a, b) => a + b, 0);
 						if (reactionsCount === 0) {
 							myReactionsMap.set(note.id, null);
-						} else if (reactionsCount <= note.reactionAndUserPairCache.length) {
-							const pair = note.reactionAndUserPairCache.find(p => p.startsWith(meId));
-							myReactionsMap.set(note.id, pair ? pair.split('/')[1] : null);
+						} else if (reactionsCount <= note.reactionAndUserPairCache.length + (bufferdReactions?.get(note.id)?.pairs.length ?? 0)) {
+							const pairInBuffer = bufferdReactions?.get(note.id)?.pairs.find(p => p[0] === meId);
+							if (pairInBuffer) {
+								myReactionsMap.set(note.id, pairInBuffer[1]);
+							} else {
+								const pair = note.reactionAndUserPairCache.find(p => p.startsWith(meId));
+								myReactionsMap.set(note.id, pair ? pair.split('/')[1] : null);
+							}
 						} else {
 							idsNeedFetchMyReaction.add(note.id);
 						}
@@ -461,6 +510,7 @@ export class NoteEntityService implements OnModuleInit {
 		return await Promise.all(notes.map(n => this.pack(n, me, {
 			...options,
 			_hint_: {
+				bufferdReactions,
 				myReactions: myReactionsMap,
 				packedFiles,
 				packedUsers,