perf(server): Reduce database query

src/misc/populate-emojis.ts

+import { In } from 'typeorm';
 import { Emojis } from '../models';
 import { Emoji } from '../models/entities/emoji';
+import { Note } from '../models/entities/note';
 import { Cache } from './cache';
 import { isSelfHost, toPunyNullable } from './convert-host';
+import { decodeReaction } from './reaction-lib';
 
 const cache = new Cache<Emoji | null>(1000 * 60 * 60);
 
@@ -70,3 +73,47 @@ export async function populateEmojis(emojiNames: string[], noteUserHost: string
 	return emojis.filter((x): x is PopulatedEmoji => x != null);
 }
 
+export function aggregateNoteEmojis(notes: Note[]) {
+	let emojis: { name: string | null; host: string | null; }[] = [];
+	for (const note of notes) {
+		emojis = emojis.concat(note.emojis
+			.map(e => parseEmojiStr(e, note.userHost)));
+		if (note.renote) {
+			emojis = emojis.concat(note.renote.emojis
+				.map(e => parseEmojiStr(e, note.renote!.userHost)));
+			if (note.renote.user) {
+				emojis = emojis.concat(note.renote.user.emojis
+					.map(e => parseEmojiStr(e, note.renote!.userHost)));
+			}
+		}
+		const customReactions = Object.keys(note.reactions).map(x => decodeReaction(x)).filter(x => x.name != null) as typeof emojis;
+		emojis = emojis.concat(customReactions);
+		if (note.user) {
+			emojis = emojis.concat(note.user.emojis
+				.map(e => parseEmojiStr(e, note.userHost)));
+		}
+	}
+	return emojis.filter(x => x.name != null) as { name: string; host: string | null; }[];
+}
+
+/**
+ * 与えられた絵文字のリストをデータベースから取得し、キャッシュに追加します
+ */
+export async function prefetchEmojis(emojis: { name: string; host: string | null; }[]): Promise<void> {
+	const notCachedEmojis = emojis.filter(emoji => cache.get(`${emoji.name} ${emoji.host}`) == null);
+	const emojisQuery: any[] = [];
+	const hosts = new Set(notCachedEmojis.map(e => e.host));
+	for (const host of hosts) {
+		emojisQuery.push({
+			name: In(notCachedEmojis.filter(e => e.host === host).map(e => e.name)),
+			host: host
+		});
+	}
+	const _emojis = emojisQuery.length > 0 ? await Emojis.find({
+		where: emojisQuery,
+		select: ['name', 'host', 'url']
+	}) : [];
+	for (const emoji of _emojis) {
+		cache.set(`${emoji.name} ${emoji.host}`, emoji);
+	}
+}

src/models/repositories/note.ts

@@ -8,7 +8,7 @@ import { convertLegacyReaction, convertLegacyReactions, decodeReaction } from '.
 import { toString } from '../../mfm/to-string';
 import { parse } from '../../mfm/parse';
 import { NoteReaction } from '../entities/note-reaction';
-import { populateEmojis } from '../../misc/populate-emojis';
+import { aggregateNoteEmojis, populateEmojis, prefetchEmojis } from '../../misc/populate-emojis';
 
 export type PackedNote = SchemaType<typeof packedNoteSchema>;
 
@@ -259,6 +259,8 @@ export class NoteRepository extends Repository<Note> {
 			}
 		}
 
+		await prefetchEmojis(aggregateNoteEmojis(notes));
+
 		return await Promise.all(notes.map(n => this.pack(n, me, {
 			...options,
 			_hint_: {

src/models/repositories/notification.ts

@@ -6,6 +6,7 @@ import { SchemaType } from '../../misc/schema';
 import { Note } from '../entities/note';
 import { NoteReaction } from '../entities/note-reaction';
 import { User } from '../entities/user';
+import { aggregateNoteEmojis, prefetchEmojis } from '../../misc/populate-emojis';
 
 export type PackedNotification = SchemaType<typeof packedNotificationSchema>;
 
@@ -98,6 +99,8 @@ export class NotificationRepository extends Repository<Notification> {
 			myReactionsMap.set(target, myReactions.find(reaction => reaction.noteId === target) || null);
 		}
 
+		await prefetchEmojis(aggregateNoteEmojis(notes));
+
 		return await Promise.all(notifications.map(x => this.pack(x, {
 			_hintForEachNotes_: {
 				myReactions: myReactionsMap