perf(backend): ノートのリアクション情報をキャッシュすることでDBへのクエリを削減

packages/backend/src/models/Note.ts

@@ -164,6 +164,11 @@ export class MiNote {
 	})
 	public mentionedRemoteUsers: string;
 
+	@Column('varchar', {
+		length: 1024, array: true, default: '{}',
+	})
+	public reactionAndUserPairCache: string[];
+
 	@Column('varchar', {
 		length: 128, array: true, default: '{}',
 	})

packages/backend/src/models/json-schema/note.ts

@@ -174,6 +174,14 @@ export const packedNoteSchema = {
 			type: 'string',
 			optional: true, nullable: false,
 		},
+		reactionAndUserPairCache: {
+			type: 'array',
+			optional: true, nullable: false,
+			items: {
+				type: 'string',
+				optional: false, nullable: false,
+			},
+		},
 
 		myReaction: {
 			type: 'object',