enhance(backend): make ftt db fallback configurable

6 files changed, 350 insertions, 285 deletions

diff --git a/packages/backend/src/server/api/endpoints/admin/meta.ts b/packages/backend/src/server/api/endpoints/admin/meta.ts
index 73c84a8674..cc9afaf7fd 100644
--- a/packages/backend/src/server/api/endpoints/admin/meta.ts
+++ b/packages/backend/src/server/api/endpoints/admin/meta.ts
@@ -295,6 +295,10 @@ export const meta = {
 				type: 'boolean',
 				optional: false, nullable: false,
 			},
+			enableFanoutTimelineDbFallback: {
+				type: 'boolean',
+				optional: false, nullable: false,
+			},
 			perLocalUserUserTimelineCacheMax: {
 				type: 'number',
 				optional: false, nullable: false,
@@ -424,6 +428,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				policies: { ...DEFAULT_POLICIES, ...instance.policies },
 				manifestJsonOverride: instance.manifestJsonOverride,
 				enableFanoutTimeline: instance.enableFanoutTimeline,
+				enableFanoutTimelineDbFallback: instance.enableFanoutTimelineDbFallback,
 				perLocalUserUserTimelineCacheMax: instance.perLocalUserUserTimelineCacheMax,
 				perRemoteUserUserTimelineCacheMax: instance.perRemoteUserUserTimelineCacheMax,
 				perUserHomeTimelineCacheMax: instance.perUserHomeTimelineCacheMax,
diff --git a/packages/backend/src/server/api/endpoints/admin/update-meta.ts b/packages/backend/src/server/api/endpoints/admin/update-meta.ts
index c58569a31c..da3e5dd9ac 100644
--- a/packages/backend/src/server/api/endpoints/admin/update-meta.ts
+++ b/packages/backend/src/server/api/endpoints/admin/update-meta.ts
@@ -121,6 +121,7 @@ export const paramDef = {
 		preservedUsernames: { type: 'array', items: { type: 'string' } },
 		manifestJsonOverride: { type: 'string' },
 		enableFanoutTimeline: { type: 'boolean' },
+		enableFanoutTimelineDbFallback: { type: 'boolean' },
 		perLocalUserUserTimelineCacheMax: { type: 'integer' },
 		perRemoteUserUserTimelineCacheMax: { type: 'integer' },
 		perUserHomeTimelineCacheMax: { type: 'integer' },
@@ -485,6 +486,10 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				set.enableFanoutTimeline = ps.enableFanoutTimeline;
 			}
 
+			if (ps.enableFanoutTimelineDbFallback !== undefined) {
+				set.enableFanoutTimelineDbFallback = ps.enableFanoutTimelineDbFallback;
+			}
+
 			if (ps.perLocalUserUserTimelineCacheMax !== undefined) {
 				set.perLocalUserUserTimelineCacheMax = ps.perLocalUserUserTimelineCacheMax;
 			}
diff --git a/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts b/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
index 19c24a78f4..408c2fa371 100644
--- a/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
@@ -93,87 +93,100 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			const serverSettings = await this.metaService.fetch();
 
-			if (serverSettings.enableFanoutTimeline) {
-				const [
-					userIdsWhoMeMuting,
-					userIdsWhoMeMutingRenotes,
-					userIdsWhoBlockingMe,
-				] = await Promise.all([
-					this.cacheService.userMutingsCache.fetch(me.id),
-					this.cacheService.renoteMutingsCache.fetch(me.id),
-					this.cacheService.userBlockedCache.fetch(me.id),
-				]);
+			if (!serverSettings.enableFanoutTimeline) {
+				return await this.getFromDb({
+					untilId,
+					sinceId,
+					limit: ps.limit,
+					includeMyRenotes: ps.includeMyRenotes,
+					includeRenotedMyNotes: ps.includeRenotedMyNotes,
+					includeLocalRenotes: ps.includeLocalRenotes,
+					withFiles: ps.withFiles,
+					withReplies: ps.withReplies,
+				}, me);
+			}
 
-				let noteIds: string[];
-				let shouldFallbackToDb = false;
+			const [
+				userIdsWhoMeMuting,
+				userIdsWhoMeMutingRenotes,
+				userIdsWhoBlockingMe,
+			] = await Promise.all([
+				this.cacheService.userMutingsCache.fetch(me.id),
+				this.cacheService.renoteMutingsCache.fetch(me.id),
+				this.cacheService.userBlockedCache.fetch(me.id),
+			]);
 
-				if (ps.withFiles) {
-					const [htlNoteIds, ltlNoteIds] = await this.funoutTimelineService.getMulti([
-						`homeTimelineWithFiles:${me.id}`,
-						'localTimelineWithFiles',
-					], untilId, sinceId);
-					noteIds = Array.from(new Set([...htlNoteIds, ...ltlNoteIds]));
-				} else if (ps.withReplies) {
-					const [htlNoteIds, ltlNoteIds, ltlReplyNoteIds] = await this.funoutTimelineService.getMulti([
-						`homeTimeline:${me.id}`,
-						'localTimeline',
-						'localTimelineWithReplies',
-					], untilId, sinceId);
-					noteIds = Array.from(new Set([...htlNoteIds, ...ltlNoteIds, ...ltlReplyNoteIds]));
-				} else {
-					const [htlNoteIds, ltlNoteIds] = await this.funoutTimelineService.getMulti([
-						`homeTimeline:${me.id}`,
-						'localTimeline',
-					], untilId, sinceId);
-					noteIds = Array.from(new Set([...htlNoteIds, ...ltlNoteIds]));
-					shouldFallbackToDb = htlNoteIds.length === 0;
-				}
+			let noteIds: string[];
+			let shouldFallbackToDb = false;
 
-				noteIds.sort((a, b) => a > b ? -1 : 1);
-				noteIds = noteIds.slice(0, ps.limit);
+			if (ps.withFiles) {
+				const [htlNoteIds, ltlNoteIds] = await this.funoutTimelineService.getMulti([
+					`homeTimelineWithFiles:${me.id}`,
+					'localTimelineWithFiles',
+				], untilId, sinceId);
+				noteIds = Array.from(new Set([...htlNoteIds, ...ltlNoteIds]));
+			} else if (ps.withReplies) {
+				const [htlNoteIds, ltlNoteIds, ltlReplyNoteIds] = await this.funoutTimelineService.getMulti([
+					`homeTimeline:${me.id}`,
+					'localTimeline',
+					'localTimelineWithReplies',
+				], untilId, sinceId);
+				noteIds = Array.from(new Set([...htlNoteIds, ...ltlNoteIds, ...ltlReplyNoteIds]));
+			} else {
+				const [htlNoteIds, ltlNoteIds] = await this.funoutTimelineService.getMulti([
+					`homeTimeline:${me.id}`,
+					'localTimeline',
+				], untilId, sinceId);
+				noteIds = Array.from(new Set([...htlNoteIds, ...ltlNoteIds]));
+				shouldFallbackToDb = htlNoteIds.length === 0;
+			}
 
-				shouldFallbackToDb = shouldFallbackToDb || (noteIds.length === 0);
+			noteIds.sort((a, b) => a > b ? -1 : 1);
+			noteIds = noteIds.slice(0, ps.limit);
 
-				let redisTimeline: MiNote[] = [];
+			shouldFallbackToDb = shouldFallbackToDb || (noteIds.length === 0);
 
-				if (!shouldFallbackToDb) {
-					const query = this.notesRepository.createQueryBuilder('note')
-						.where('note.id IN (:...noteIds)', { noteIds: noteIds })
-						.innerJoinAndSelect('note.user', 'user')
-						.leftJoinAndSelect('note.reply', 'reply')
-						.leftJoinAndSelect('note.renote', 'renote')
-						.leftJoinAndSelect('reply.user', 'replyUser')
-						.leftJoinAndSelect('renote.user', 'renoteUser')
-						.leftJoinAndSelect('note.channel', 'channel');
+			let redisTimeline: MiNote[] = [];
 
-					redisTimeline = await query.getMany();
+			if (!shouldFallbackToDb) {
+				const query = this.notesRepository.createQueryBuilder('note')
+					.where('note.id IN (:...noteIds)', { noteIds: noteIds })
+					.innerJoinAndSelect('note.user', 'user')
+					.leftJoinAndSelect('note.reply', 'reply')
+					.leftJoinAndSelect('note.renote', 'renote')
+					.leftJoinAndSelect('reply.user', 'replyUser')
+					.leftJoinAndSelect('renote.user', 'renoteUser')
+					.leftJoinAndSelect('note.channel', 'channel');
 
-					redisTimeline = redisTimeline.filter(note => {
-						if (note.userId === me.id) {
-							return true;
-						}
-						if (isUserRelated(note, userIdsWhoBlockingMe)) return false;
-						if (isUserRelated(note, userIdsWhoMeMuting)) return false;
-						if (note.renoteId) {
-							if (note.text == null && note.fileIds.length === 0 && !note.hasPoll) {
-								if (isUserRelated(note, userIdsWhoMeMutingRenotes)) return false;
-								if (ps.withRenotes === false) return false;
-							}
-						}
+				redisTimeline = await query.getMany();
 
+				redisTimeline = redisTimeline.filter(note => {
+					if (note.userId === me.id) {
 						return true;
-					});
+					}
+					if (isUserRelated(note, userIdsWhoBlockingMe)) return false;
+					if (isUserRelated(note, userIdsWhoMeMuting)) return false;
+					if (note.renoteId) {
+						if (note.text == null && note.fileIds.length === 0 && !note.hasPoll) {
+							if (isUserRelated(note, userIdsWhoMeMutingRenotes)) return false;
+							if (ps.withRenotes === false) return false;
+						}
+					}
 
-					redisTimeline.sort((a, b) => a.id > b.id ? -1 : 1);
-				}
+					return true;
+				});
 
-				if (redisTimeline.length > 0) {
-					process.nextTick(() => {
-						this.activeUsersChart.read(me);
-					});
+				redisTimeline.sort((a, b) => a.id > b.id ? -1 : 1);
+			}
 
-					return await this.noteEntityService.packMany(redisTimeline, me);
-				} else { // fallback to db
+			if (redisTimeline.length > 0) {
+				process.nextTick(() => {
+					this.activeUsersChart.read(me);
+				});
+
+				return await this.noteEntityService.packMany(redisTimeline, me);
+			} else {
+				if (serverSettings.enableFanoutTimelineDbFallback) { // fallback to db
 					return await this.getFromDb({
 						untilId,
 						sinceId,
@@ -184,18 +197,9 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 						withFiles: ps.withFiles,
 						withReplies: ps.withReplies,
 					}, me);
+				} else {
+					return [];
 				}
-			} else {
-				return await this.getFromDb({
-					untilId,
-					sinceId,
-					limit: ps.limit,
-					includeMyRenotes: ps.includeMyRenotes,
-					includeRenotedMyNotes: ps.includeRenotedMyNotes,
-					includeLocalRenotes: ps.includeLocalRenotes,
-					withFiles: ps.withFiles,
-					withReplies: ps.withReplies,
-				}, me);
 			}
 		});
 	}
diff --git a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
index 94a640e70a..003dae6614 100644
--- a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
@@ -84,75 +84,85 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			const serverSettings = await this.metaService.fetch();
 
-			if (serverSettings.enableFanoutTimeline) {
-				const [
-					userIdsWhoMeMuting,
-					userIdsWhoMeMutingRenotes,
-					userIdsWhoBlockingMe,
-				] = me ? await Promise.all([
-					this.cacheService.userMutingsCache.fetch(me.id),
-					this.cacheService.renoteMutingsCache.fetch(me.id),
-					this.cacheService.userBlockedCache.fetch(me.id),
-				]) : [new Set<string>(), new Set<string>(), new Set<string>()];
+			if (!serverSettings.enableFanoutTimeline) {
+				return await this.getFromDb({
+					untilId,
+					sinceId,
+					limit: ps.limit,
+					withFiles: ps.withFiles,
+					withReplies: ps.withReplies,
+				}, me);
+			}
 
-				let noteIds: string[];
+			const [
+				userIdsWhoMeMuting,
+				userIdsWhoMeMutingRenotes,
+				userIdsWhoBlockingMe,
+			] = me ? await Promise.all([
+				this.cacheService.userMutingsCache.fetch(me.id),
+				this.cacheService.renoteMutingsCache.fetch(me.id),
+				this.cacheService.userBlockedCache.fetch(me.id),
+			]) : [new Set<string>(), new Set<string>(), new Set<string>()];
 
-				if (ps.withFiles) {
-					noteIds = await this.funoutTimelineService.get('localTimelineWithFiles', untilId, sinceId);
-				} else {
-					const [nonReplyNoteIds, replyNoteIds] = await this.funoutTimelineService.getMulti([
-						'localTimeline',
-						'localTimelineWithReplies',
-					], untilId, sinceId);
-					noteIds = Array.from(new Set([...nonReplyNoteIds, ...replyNoteIds]));
-					noteIds.sort((a, b) => a > b ? -1 : 1);
-				}
+			let noteIds: string[];
 
-				noteIds = noteIds.slice(0, ps.limit);
+			if (ps.withFiles) {
+				noteIds = await this.funoutTimelineService.get('localTimelineWithFiles', untilId, sinceId);
+			} else {
+				const [nonReplyNoteIds, replyNoteIds] = await this.funoutTimelineService.getMulti([
+					'localTimeline',
+					'localTimelineWithReplies',
+				], untilId, sinceId);
+				noteIds = Array.from(new Set([...nonReplyNoteIds, ...replyNoteIds]));
+				noteIds.sort((a, b) => a > b ? -1 : 1);
+			}
 
-				let redisTimeline: MiNote[] = [];
+			noteIds = noteIds.slice(0, ps.limit);
 
-				if (noteIds.length > 0) {
-					const query = this.notesRepository.createQueryBuilder('note')
-						.where('note.id IN (:...noteIds)', { noteIds: noteIds })
-						.innerJoinAndSelect('note.user', 'user')
-						.leftJoinAndSelect('note.reply', 'reply')
-						.leftJoinAndSelect('note.renote', 'renote')
-						.leftJoinAndSelect('reply.user', 'replyUser')
-						.leftJoinAndSelect('renote.user', 'renoteUser')
-						.leftJoinAndSelect('note.channel', 'channel');
+			let redisTimeline: MiNote[] = [];
 
-					redisTimeline = await query.getMany();
+			if (noteIds.length > 0) {
+				const query = this.notesRepository.createQueryBuilder('note')
+					.where('note.id IN (:...noteIds)', { noteIds: noteIds })
+					.innerJoinAndSelect('note.user', 'user')
+					.leftJoinAndSelect('note.reply', 'reply')
+					.leftJoinAndSelect('note.renote', 'renote')
+					.leftJoinAndSelect('reply.user', 'replyUser')
+					.leftJoinAndSelect('renote.user', 'renoteUser')
+					.leftJoinAndSelect('note.channel', 'channel');
 
-					redisTimeline = redisTimeline.filter(note => {
-						if (me && (note.userId === me.id)) {
-							return true;
-						}
-						if (!ps.withReplies && note.replyId && note.replyUserId !== note.userId && (me == null || note.replyUserId !== me.id)) return false;
-						if (me && isUserRelated(note, userIdsWhoBlockingMe)) return false;
-						if (me && isUserRelated(note, userIdsWhoMeMuting)) return false;
-						if (note.renoteId) {
-							if (note.text == null && note.fileIds.length === 0 && !note.hasPoll) {
-								if (me && isUserRelated(note, userIdsWhoMeMutingRenotes)) return false;
-								if (ps.withRenotes === false) return false;
-							}
-						}
+				redisTimeline = await query.getMany();
 
+				redisTimeline = redisTimeline.filter(note => {
+					if (me && (note.userId === me.id)) {
 						return true;
-					});
+					}
+					if (!ps.withReplies && note.replyId && note.replyUserId !== note.userId && (me == null || note.replyUserId !== me.id)) return false;
+					if (me && isUserRelated(note, userIdsWhoBlockingMe)) return false;
+					if (me && isUserRelated(note, userIdsWhoMeMuting)) return false;
+					if (note.renoteId) {
+						if (note.text == null && note.fileIds.length === 0 && !note.hasPoll) {
+							if (me && isUserRelated(note, userIdsWhoMeMutingRenotes)) return false;
+							if (ps.withRenotes === false) return false;
+						}
+					}
 
-					redisTimeline.sort((a, b) => a.id > b.id ? -1 : 1);
-				}
+					return true;
+				});
 
-				if (redisTimeline.length > 0) {
-					process.nextTick(() => {
-						if (me) {
-							this.activeUsersChart.read(me);
-						}
-					});
+				redisTimeline.sort((a, b) => a.id > b.id ? -1 : 1);
+			}
+
+			if (redisTimeline.length > 0) {
+				process.nextTick(() => {
+					if (me) {
+						this.activeUsersChart.read(me);
+					}
+				});
 
-					return await this.noteEntityService.packMany(redisTimeline, me);
-				} else { // fallback to db
+				return await this.noteEntityService.packMany(redisTimeline, me);
+			} else {
+				if (serverSettings.enableFanoutTimelineDbFallback) { // fallback to db
 					return await this.getFromDb({
 						untilId,
 						sinceId,
@@ -160,15 +170,9 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 						withFiles: ps.withFiles,
 						withReplies: ps.withReplies,
 					}, me);
+				} else {
+					return [];
 				}
-			} else {
-				return await this.getFromDb({
-					untilId,
-					sinceId,
-					limit: ps.limit,
-					withFiles: ps.withFiles,
-					withReplies: ps.withReplies,
-				}, me);
 			}
 		});
 	}
diff --git a/packages/backend/src/server/api/endpoints/notes/timeline.ts b/packages/backend/src/server/api/endpoints/notes/timeline.ts
index 5016bd3acb..8037d4862f 100644
--- a/packages/backend/src/server/api/endpoints/notes/timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/timeline.ts
@@ -76,65 +76,78 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			const serverSettings = await this.metaService.fetch();
 
-			if (serverSettings.enableFanoutTimeline) {
-				const [
-					followings,
-					userIdsWhoMeMuting,
-					userIdsWhoMeMutingRenotes,
-					userIdsWhoBlockingMe,
-				] = await Promise.all([
-					this.cacheService.userFollowingsCache.fetch(me.id),
-					this.cacheService.userMutingsCache.fetch(me.id),
-					this.cacheService.renoteMutingsCache.fetch(me.id),
-					this.cacheService.userBlockedCache.fetch(me.id),
-				]);
+			if (!serverSettings.enableFanoutTimeline) {
+				return await this.getFromDb({
+					untilId,
+					sinceId,
+					limit: ps.limit,
+					includeMyRenotes: ps.includeMyRenotes,
+					includeRenotedMyNotes: ps.includeRenotedMyNotes,
+					includeLocalRenotes: ps.includeLocalRenotes,
+					withFiles: ps.withFiles,
+					withRenotes: ps.withRenotes,
+				}, me);
+			}
 
-				let noteIds = await this.funoutTimelineService.get(ps.withFiles ? `homeTimelineWithFiles:${me.id}` : `homeTimeline:${me.id}`, untilId, sinceId);
-				noteIds = noteIds.slice(0, ps.limit);
+			const [
+				followings,
+				userIdsWhoMeMuting,
+				userIdsWhoMeMutingRenotes,
+				userIdsWhoBlockingMe,
+			] = await Promise.all([
+				this.cacheService.userFollowingsCache.fetch(me.id),
+				this.cacheService.userMutingsCache.fetch(me.id),
+				this.cacheService.renoteMutingsCache.fetch(me.id),
+				this.cacheService.userBlockedCache.fetch(me.id),
+			]);
 
-				let redisTimeline: MiNote[] = [];
+			let noteIds = await this.funoutTimelineService.get(ps.withFiles ? `homeTimelineWithFiles:${me.id}` : `homeTimeline:${me.id}`, untilId, sinceId);
+			noteIds = noteIds.slice(0, ps.limit);
 
-				if (noteIds.length > 0) {
-					const query = this.notesRepository.createQueryBuilder('note')
-						.where('note.id IN (:...noteIds)', { noteIds: noteIds })
-						.innerJoinAndSelect('note.user', 'user')
-						.leftJoinAndSelect('note.reply', 'reply')
-						.leftJoinAndSelect('note.renote', 'renote')
-						.leftJoinAndSelect('reply.user', 'replyUser')
-						.leftJoinAndSelect('renote.user', 'renoteUser')
-						.leftJoinAndSelect('note.channel', 'channel');
+			let redisTimeline: MiNote[] = [];
 
-					redisTimeline = await query.getMany();
+			if (noteIds.length > 0) {
+				const query = this.notesRepository.createQueryBuilder('note')
+					.where('note.id IN (:...noteIds)', { noteIds: noteIds })
+					.innerJoinAndSelect('note.user', 'user')
+					.leftJoinAndSelect('note.reply', 'reply')
+					.leftJoinAndSelect('note.renote', 'renote')
+					.leftJoinAndSelect('reply.user', 'replyUser')
+					.leftJoinAndSelect('renote.user', 'renoteUser')
+					.leftJoinAndSelect('note.channel', 'channel');
 
-					redisTimeline = redisTimeline.filter(note => {
-						if (note.userId === me.id) {
-							return true;
-						}
-						if (isUserRelated(note, userIdsWhoBlockingMe)) return false;
-						if (isUserRelated(note, userIdsWhoMeMuting)) return false;
-						if (note.renoteId) {
-							if (note.text == null && note.fileIds.length === 0 && !note.hasPoll) {
-								if (isUserRelated(note, userIdsWhoMeMutingRenotes)) return false;
-								if (ps.withRenotes === false) return false;
-							}
-						}
-						if (note.reply && note.reply.visibility === 'followers') {
-							if (!Object.hasOwn(followings, note.reply.userId)) return false;
-						}
+				redisTimeline = await query.getMany();
 
+				redisTimeline = redisTimeline.filter(note => {
+					if (note.userId === me.id) {
 						return true;
-					});
+					}
+					if (isUserRelated(note, userIdsWhoBlockingMe)) return false;
+					if (isUserRelated(note, userIdsWhoMeMuting)) return false;
+					if (note.renoteId) {
+						if (note.text == null && note.fileIds.length === 0 && !note.hasPoll) {
+							if (isUserRelated(note, userIdsWhoMeMutingRenotes)) return false;
+							if (ps.withRenotes === false) return false;
+						}
+					}
+					if (note.reply && note.reply.visibility === 'followers') {
+						if (!Object.hasOwn(followings, note.reply.userId)) return false;
+					}
 
-					redisTimeline.sort((a, b) => a.id > b.id ? -1 : 1);
-				}
+					return true;
+				});
+
+				redisTimeline.sort((a, b) => a.id > b.id ? -1 : 1);
+			}
 
-				if (redisTimeline.length > 0) {
-					process.nextTick(() => {
-						this.activeUsersChart.read(me);
-					});
+			if (redisTimeline.length > 0) {
+				process.nextTick(() => {
+					this.activeUsersChart.read(me);
+				});
 
-					return await this.noteEntityService.packMany(redisTimeline, me);
-				} else { // fallback to db
+				return await this.noteEntityService.packMany(redisTimeline, me);
+			} else {
+				if (serverSettings.enableFanoutTimelineDbFallback) { // fallback to db
 					return await this.getFromDb({
 						untilId,
 						sinceId,
@@ -145,18 +158,9 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 						withFiles: ps.withFiles,
 						withRenotes: ps.withRenotes,
 					}, me);
+				} else {
+					return [];
 				}
-			} else {
-				return await this.getFromDb({
-					untilId,
-					sinceId,
-					limit: ps.limit,
-					includeMyRenotes: ps.includeMyRenotes,
-					includeRenotedMyNotes: ps.includeRenotedMyNotes,
-					includeLocalRenotes: ps.includeLocalRenotes,
-					withFiles: ps.withFiles,
-					withRenotes: ps.withRenotes,
-				}, me);
 			}
 		});
 	}
diff --git a/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts b/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
index 9ead1410c2..dbc3875597 100644
--- a/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
@@ -4,7 +4,8 @@
  */
 
 import { Inject, Injectable } from '@nestjs/common';
-import type { MiNote, NotesRepository, UserListMembershipsRepository, UserListsRepository } from '@/models/_.js';
+import { Brackets } from 'typeorm';
+import type { MiNote, MiUserList, NotesRepository, UserListMembershipsRepository, UserListsRepository } from '@/models/_.js';
 import { Endpoint } from '@/server/api/endpoint-base.js';
 import { NoteEntityService } from '@/core/entities/NoteEntityService.js';
 import ActiveUsersChart from '@/core/chart/charts/active-users.js';
@@ -14,8 +15,9 @@ import { IdService } from '@/core/IdService.js';
 import { isUserRelated } from '@/misc/is-user-related.js';
 import { FunoutTimelineService } from '@/core/FunoutTimelineService.js';
 import { QueryService } from '@/core/QueryService.js';
+import { MiLocalUser } from '@/models/User.js';
+import { MetaService } from '@/core/MetaService.js';
 import { ApiError } from '../../error.js';
-import { Brackets } from 'typeorm';
 
 export const meta = {
 	tags: ['notes', 'lists'],
@@ -81,7 +83,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		private idService: IdService,
 		private funoutTimelineService: FunoutTimelineService,
 		private queryService: QueryService,
-
+		private metaService: MetaService,
 	) {
 		super(meta, paramDef, async (ps, me) => {
 			const untilId = ps.untilId ?? (ps.untilDate ? this.idService.gen(ps.untilDate!) : null);
@@ -96,6 +98,21 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				throw new ApiError(meta.errors.noSuchList);
 			}
 
+			const serverSettings = await this.metaService.fetch();
+
+			if (!serverSettings.enableFanoutTimeline) {
+				return await this.getFromDb(list, {
+					untilId,
+					sinceId,
+					limit: ps.limit,
+					includeMyRenotes: ps.includeMyRenotes,
+					includeRenotedMyNotes: ps.includeRenotedMyNotes,
+					includeLocalRenotes: ps.includeLocalRenotes,
+					withFiles: ps.withFiles,
+					withRenotes: ps.withRenotes,
+				}, me);
+			}
+
 			const [
 				userIdsWhoMeMuting,
 				userIdsWhoMeMutingRenotes,
@@ -145,93 +162,119 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 			if (redisTimeline.length > 0) {
 				this.activeUsersChart.read(me);
 				return await this.noteEntityService.packMany(redisTimeline, me);
-			} else { // fallback to db
-				//#region Construct query
-				const query = this.queryService.makePaginationQuery(this.notesRepository.createQueryBuilder('note'), ps.sinceId, ps.untilId)
-					.innerJoin(this.userListMembershipsRepository.metadata.targetName, 'userListMemberships', 'userListMemberships.userId = note.userId')
-					.innerJoinAndSelect('note.user', 'user')
-					.leftJoinAndSelect('note.reply', 'reply')
-					.leftJoinAndSelect('note.renote', 'renote')
-					.leftJoinAndSelect('reply.user', 'replyUser')
-					.leftJoinAndSelect('renote.user', 'renoteUser')
-					.andWhere('userListMemberships.userListId = :userListId', { userListId: list.id })
-					.andWhere('note.channelId IS NULL') // チャンネルノートではない
-					.andWhere(new Brackets(qb => {
-						qb
-							.where('note.replyId IS NULL') // 返信ではない
-							.orWhere(new Brackets(qb => {
-								qb // 返信だけど投稿者自身への返信
-									.where('note.replyId IS NOT NULL')
-									.andWhere('note.replyUserId = note.userId');
-							}))
-							.orWhere(new Brackets(qb => {
-								qb // 返信だけど自分宛ての返信
-									.where('note.replyId IS NOT NULL')
-									.andWhere('note.replyUserId = :meId', { meId: me.id });
-							}))
-							.orWhere(new Brackets(qb => {
-								qb // 返信だけどwithRepliesがtrueの場合
-									.where('note.replyId IS NOT NULL')
-									.andWhere('userListMemberships.withReplies = true');
-							}));
+			} else {
+				if (serverSettings.enableFanoutTimelineDbFallback) { // fallback to db
+					return await this.getFromDb(list, {
+						untilId,
+						sinceId,
+						limit: ps.limit,
+						includeMyRenotes: ps.includeMyRenotes,
+						includeRenotedMyNotes: ps.includeRenotedMyNotes,
+						includeLocalRenotes: ps.includeLocalRenotes,
+						withFiles: ps.withFiles,
+						withRenotes: ps.withRenotes,
+					}, me);
+				} else {
+					return [];
+				}
+			}
+		});
+	}
+
+	private async getFromDb(list: MiUserList, ps: {
+		untilId: string | null,
+		sinceId: string | null,
+		limit: number,
+		includeMyRenotes: boolean,
+		includeRenotedMyNotes: boolean,
+		includeLocalRenotes: boolean,
+		withFiles: boolean,
+		withRenotes: boolean,
+	}, me: MiLocalUser) {
+		//#region Construct query
+		const query = this.queryService.makePaginationQuery(this.notesRepository.createQueryBuilder('note'), ps.sinceId, ps.untilId)
+			.innerJoin(this.userListMembershipsRepository.metadata.targetName, 'userListMemberships', 'userListMemberships.userId = note.userId')
+			.innerJoinAndSelect('note.user', 'user')
+			.leftJoinAndSelect('note.reply', 'reply')
+			.leftJoinAndSelect('note.renote', 'renote')
+			.leftJoinAndSelect('reply.user', 'replyUser')
+			.leftJoinAndSelect('renote.user', 'renoteUser')
+			.andWhere('userListMemberships.userListId = :userListId', { userListId: list.id })
+			.andWhere('note.channelId IS NULL') // チャンネルノートではない
+			.andWhere(new Brackets(qb => {
+				qb
+					.where('note.replyId IS NULL') // 返信ではない
+					.orWhere(new Brackets(qb => {
+						qb // 返信だけど投稿者自身への返信
+							.where('note.replyId IS NOT NULL')
+							.andWhere('note.replyUserId = note.userId');
+					}))
+					.orWhere(new Brackets(qb => {
+						qb // 返信だけど自分宛ての返信
+							.where('note.replyId IS NOT NULL')
+							.andWhere('note.replyUserId = :meId', { meId: me.id });
+					}))
+					.orWhere(new Brackets(qb => {
+						qb // 返信だけどwithRepliesがtrueの場合
+							.where('note.replyId IS NOT NULL')
+							.andWhere('userListMemberships.withReplies = true');
 					}));
+			}));
 
-				this.queryService.generateVisibilityQuery(query, me);
-				this.queryService.generateMutedUserQuery(query, me);
-				this.queryService.generateBlockedUserQuery(query, me);
-				this.queryService.generateMutedUserRenotesQueryForNotes(query, me);
+		this.queryService.generateVisibilityQuery(query, me);
+		this.queryService.generateMutedUserQuery(query, me);
+		this.queryService.generateBlockedUserQuery(query, me);
+		this.queryService.generateMutedUserRenotesQueryForNotes(query, me);
 
-				if (ps.includeMyRenotes === false) {
-					query.andWhere(new Brackets(qb => {
-						qb.orWhere('note.userId != :meId', { meId: me.id });
-						qb.orWhere('note.renoteId IS NULL');
-						qb.orWhere('note.text IS NOT NULL');
-						qb.orWhere('note.fileIds != \'{}\'');
-						qb.orWhere('0 < (SELECT COUNT(*) FROM poll WHERE poll."noteId" = note.id)');
-					}));
-				}
+		if (ps.includeMyRenotes === false) {
+			query.andWhere(new Brackets(qb => {
+				qb.orWhere('note.userId != :meId', { meId: me.id });
+				qb.orWhere('note.renoteId IS NULL');
+				qb.orWhere('note.text IS NOT NULL');
+				qb.orWhere('note.fileIds != \'{}\'');
+				qb.orWhere('0 < (SELECT COUNT(*) FROM poll WHERE poll."noteId" = note.id)');
+			}));
+		}
 
-				if (ps.includeRenotedMyNotes === false) {
-					query.andWhere(new Brackets(qb => {
-						qb.orWhere('note.renoteUserId != :meId', { meId: me.id });
-						qb.orWhere('note.renoteId IS NULL');
-						qb.orWhere('note.text IS NOT NULL');
-						qb.orWhere('note.fileIds != \'{}\'');
-						qb.orWhere('0 < (SELECT COUNT(*) FROM poll WHERE poll."noteId" = note.id)');
-					}));
-				}
+		if (ps.includeRenotedMyNotes === false) {
+			query.andWhere(new Brackets(qb => {
+				qb.orWhere('note.renoteUserId != :meId', { meId: me.id });
+				qb.orWhere('note.renoteId IS NULL');
+				qb.orWhere('note.text IS NOT NULL');
+				qb.orWhere('note.fileIds != \'{}\'');
+				qb.orWhere('0 < (SELECT COUNT(*) FROM poll WHERE poll."noteId" = note.id)');
+			}));
+		}
 
-				if (ps.includeLocalRenotes === false) {
-					query.andWhere(new Brackets(qb => {
-						qb.orWhere('note.renoteUserHost IS NOT NULL');
-						qb.orWhere('note.renoteId IS NULL');
-						qb.orWhere('note.text IS NOT NULL');
-						qb.orWhere('note.fileIds != \'{}\'');
-						qb.orWhere('0 < (SELECT COUNT(*) FROM poll WHERE poll."noteId" = note.id)');
-					}));
-				}
+		if (ps.includeLocalRenotes === false) {
+			query.andWhere(new Brackets(qb => {
+				qb.orWhere('note.renoteUserHost IS NOT NULL');
+				qb.orWhere('note.renoteId IS NULL');
+				qb.orWhere('note.text IS NOT NULL');
+				qb.orWhere('note.fileIds != \'{}\'');
+				qb.orWhere('0 < (SELECT COUNT(*) FROM poll WHERE poll."noteId" = note.id)');
+			}));
+		}
 
-				if (ps.withRenotes === false) {
-					query.andWhere(new Brackets(qb => {
-						qb.orWhere('note.renoteId IS NULL');
-						qb.orWhere(new Brackets(qb => {
-							qb.orWhere('note.text IS NOT NULL');
-							qb.orWhere('note.fileIds != \'{}\'');
-						}));
-					}));
-				}
+		if (ps.withRenotes === false) {
+			query.andWhere(new Brackets(qb => {
+				qb.orWhere('note.renoteId IS NULL');
+				qb.orWhere(new Brackets(qb => {
+					qb.orWhere('note.text IS NOT NULL');
+					qb.orWhere('note.fileIds != \'{}\'');
+				}));
+			}));
+		}
 
-				if (ps.withFiles) {
-					query.andWhere('note.fileIds != \'{}\'');
-				}
-				//#endregion
+		if (ps.withFiles) {
+			query.andWhere('note.fileIds != \'{}\'');
+		}
+		//#endregion
 
-				const timeline = await query.limit(ps.limit).getMany();
+		const timeline = await query.limit(ps.limit).getMany();
 
-				this.activeUsersChart.read(me);
+		this.activeUsersChart.read(me);
 
-				return await this.noteEntityService.packMany(timeline, me);
-			}
-		});
+		return await this.noteEntityService.packMany(timeline, me);
 	}
 }