fix: resolve N+1 queries, add indexes, and improve DB operations

- Batch-fetch tags for notes in a single query instead of per-note loops
- Add composite indexes on notes, note_tags, and sync_log tables
- Wrap sync push in a transaction for atomicity
- Replace O(n) cleanExpiredSessions with single DELETE query
- Use SQL WHERE in getChangesSince instead of loading all notes
- Extract shared syncNoteTags utility to eliminate duplication
- Add root +error.svelte boundary matching app theme

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib/server/auth.ts

@@ -1,6 +1,6 @@
 import { db } from './db/index.js';
 import { users, sessions } from './db/schema.js';
-import { eq } from 'drizzle-orm';
+import { eq, lt } from 'drizzle-orm';
 import * as argon2 from 'argon2';
 import { randomBytes } from 'crypto';
 
@@ -61,12 +61,5 @@ export async function deleteSession(token: string): Promise<void> {
 }
 
 export async function cleanExpiredSessions(): Promise<void> {
-	const now = new Date();
-	// Delete all expired sessions by checking each one
-	const allSessions = await db.select().from(sessions);
-	for (const session of allSessions) {
-		if (session.expiresAt < now) {
-			await db.delete(sessions).where(eq(sessions.id, session.id));
-		}
-	}
+	await db.delete(sessions).where(lt(sessions.expiresAt, new Date()));
 }

src/lib/server/db/index.ts

@@ -76,6 +76,12 @@ sqlite.exec(`
 		timestamp INTEGER NOT NULL,
 		client_id TEXT NOT NULL
 	);
+
+	CREATE INDEX IF NOT EXISTS notes_trashed_archived_idx ON notes(trashed, archived);
+	CREATE INDEX IF NOT EXISTS notes_updated_at_idx ON notes(updated_at);
+	CREATE INDEX IF NOT EXISTS note_tags_note_id_idx ON note_tags(note_id);
+	CREATE INDEX IF NOT EXISTS note_tags_tag_id_idx ON note_tags(tag_id);
+	CREATE INDEX IF NOT EXISTS sync_log_timestamp_idx ON sync_log(timestamp);
 `);
 
 export const db = drizzle(sqlite, { schema });

src/lib/server/db/schema.ts

@@ -1,4 +1,4 @@
-import { sqliteTable, text, integer, uniqueIndex } from 'drizzle-orm/sqlite-core';
+import { sqliteTable, text, integer, uniqueIndex, index } from 'drizzle-orm/sqlite-core';
 
 export const users = sqliteTable('users', {
 	id: integer('id').primaryKey({ autoIncrement: true }),
@@ -14,21 +14,28 @@ export const sessions = sqliteTable('sessions', {
 	expiresAt: integer('expires_at', { mode: 'timestamp' }).notNull()
 });
 
-export const notes = sqliteTable('notes', {
-	id: text('id').primaryKey(),
-	title: text('title').default('').notNull(),
-	content: text('content').default('').notNull(),
-	color: text('color').default('default').notNull(),
-	pinned: integer('pinned', { mode: 'boolean' }).default(false).notNull(),
-	archived: integer('archived', { mode: 'boolean' }).default(false).notNull(),
-	trashed: integer('trashed', { mode: 'boolean' }).default(false).notNull(),
-	trashedAt: integer('trashed_at', { mode: 'timestamp' }),
-	checklistMode: integer('checklist_mode', { mode: 'boolean' }).default(false).notNull(),
-	sortOrder: integer('sort_order').default(0).notNull(),
-	createdAt: integer('created_at', { mode: 'timestamp' }).notNull(),
-	updatedAt: integer('updated_at', { mode: 'timestamp' }).notNull(),
-	version: integer('version').default(1).notNull()
-});
+export const notes = sqliteTable(
+	'notes',
+	{
+		id: text('id').primaryKey(),
+		title: text('title').default('').notNull(),
+		content: text('content').default('').notNull(),
+		color: text('color').default('default').notNull(),
+		pinned: integer('pinned', { mode: 'boolean' }).default(false).notNull(),
+		archived: integer('archived', { mode: 'boolean' }).default(false).notNull(),
+		trashed: integer('trashed', { mode: 'boolean' }).default(false).notNull(),
+		trashedAt: integer('trashed_at', { mode: 'timestamp' }),
+		checklistMode: integer('checklist_mode', { mode: 'boolean' }).default(false).notNull(),
+		sortOrder: integer('sort_order').default(0).notNull(),
+		createdAt: integer('created_at', { mode: 'timestamp' }).notNull(),
+		updatedAt: integer('updated_at', { mode: 'timestamp' }).notNull(),
+		version: integer('version').default(1).notNull()
+	},
+	(table) => [
+		index('notes_trashed_archived_idx').on(table.trashed, table.archived),
+		index('notes_updated_at_idx').on(table.updatedAt)
+	]
+);
 
 export const tags = sqliteTable(
 	'tags',
@@ -39,14 +46,21 @@ export const tags = sqliteTable(
 	(table) => [uniqueIndex('tags_name_unique').on(table.name)]
 );
 
-export const noteTags = sqliteTable('note_tags', {
-	noteId: text('note_id')
-		.references(() => notes.id, { onDelete: 'cascade' })
-		.notNull(),
-	tagId: integer('tag_id')
-		.references(() => tags.id, { onDelete: 'cascade' })
-		.notNull()
-});
+export const noteTags = sqliteTable(
+	'note_tags',
+	{
+		noteId: text('note_id')
+			.references(() => notes.id, { onDelete: 'cascade' })
+			.notNull(),
+		tagId: integer('tag_id')
+			.references(() => tags.id, { onDelete: 'cascade' })
+			.notNull()
+	},
+	(table) => [
+		index('note_tags_note_id_idx').on(table.noteId),
+		index('note_tags_tag_id_idx').on(table.tagId)
+	]
+);
 
 export const attachments = sqliteTable('attachments', {
 	id: text('id').primaryKey(),
@@ -60,12 +74,16 @@ export const attachments = sqliteTable('attachments', {
 	createdAt: integer('created_at', { mode: 'timestamp' }).notNull()
 });
 
-export const syncLog = sqliteTable('sync_log', {
-	id: integer('id').primaryKey({ autoIncrement: true }),
-	noteId: text('note_id')
-		.references(() => notes.id)
-		.notNull(),
-	operation: text('operation').notNull(),
-	timestamp: integer('timestamp', { mode: 'timestamp' }).notNull(),
-	clientId: text('client_id').notNull()
-});
+export const syncLog = sqliteTable(
+	'sync_log',
+	{
+		id: integer('id').primaryKey({ autoIncrement: true }),
+		noteId: text('note_id')
+			.references(() => notes.id)
+			.notNull(),
+		operation: text('operation').notNull(),
+		timestamp: integer('timestamp', { mode: 'timestamp' }).notNull(),
+		clientId: text('client_id').notNull()
+	},
+	(table) => [index('sync_log_timestamp_idx').on(table.timestamp)]
+);

src/lib/server/tags.ts

@@ -0,0 +1,46 @@
+import { db } from './db/index.js';
+import { noteTags, tags } from './db/schema.js';
+import { eq, inArray } from 'drizzle-orm';
+
+/**
+ * Batch fetch tags for multiple notes in a single query.
+ * Returns a Map of noteId → tag names.
+ */
+export function fetchTagsForNotes(noteIds: string[]): Map<string, string[]> {
+	if (noteIds.length === 0) return new Map();
+
+	const rows = db
+		.select({ noteId: noteTags.noteId, name: tags.name })
+		.from(noteTags)
+		.innerJoin(tags, eq(noteTags.tagId, tags.id))
+		.where(inArray(noteTags.noteId, noteIds))
+		.all();
+
+	const map = new Map<string, string[]>();
+	for (const row of rows) {
+		const existing = map.get(row.noteId);
+		if (existing) {
+			existing.push(row.name);
+		} else {
+			map.set(row.noteId, [row.name]);
+		}
+	}
+	return map;
+}
+
+/**
+ * Sync tags for a note: removes old associations, upserts tags, creates new associations.
+ * Should be called within a transaction for atomicity.
+ */
+export function syncNoteTags(noteId: string, tagNames: string[]) {
+	db.delete(noteTags).where(eq(noteTags.noteId, noteId)).run();
+
+	for (const name of tagNames) {
+		let tagRow = db.select().from(tags).where(eq(tags.name, name)).get();
+		if (!tagRow) {
+			const result = db.insert(tags).values({ name }).returning().all();
+			tagRow = result[0];
+		}
+		db.insert(noteTags).values({ noteId, tagId: tagRow.id }).run();
+	}
+}

src/lib/sync/server.ts

@@ -7,65 +7,74 @@ import type { SyncQueueItem } from './idb.js';
  * Process incoming sync changes from client.
  */
 export async function processSyncPush(changes: SyncQueueItem[]): Promise<void> {
-	for (const change of changes) {
-		switch (change.operation) {
-			case 'create':
-			case 'update': {
-				if (!change.data) continue;
-				const existing = await db.select().from(notes).where(eq(notes.id, change.noteId)).get();
+	db.transaction((tx) => {
+		for (const change of changes) {
+			switch (change.operation) {
+				case 'create':
+				case 'update': {
+					if (!change.data) continue;
+					const existing = tx
+						.select()
+						.from(notes)
+						.where(eq(notes.id, change.noteId))
+						.get();
 
-				if (existing) {
-					// LWW: only update if incoming timestamp is newer
-					if (change.timestamp > existing.updatedAt.getTime()) {
-						await db
-							.update(notes)
-							.set({
-								...change.data,
+					if (existing) {
+						if (change.timestamp > existing.updatedAt.getTime()) {
+							tx.update(notes)
+								.set({
+									...change.data,
+									updatedAt: new Date(change.timestamp),
+									version: existing.version + 1
+								})
+								.where(eq(notes.id, change.noteId))
+								.run();
+						}
+					} else if (change.operation === 'create' && change.data) {
+						tx.insert(notes)
+							.values({
+								id: change.noteId,
+								title: change.data.title || '',
+								content: change.data.content || '',
+								color: change.data.color || 'default',
+								pinned: change.data.pinned || false,
+								archived: change.data.archived || false,
+								trashed: change.data.trashed || false,
+								checklistMode: change.data.checklistMode || false,
+								sortOrder: change.data.sortOrder || 0,
+								createdAt: new Date(change.timestamp),
 								updatedAt: new Date(change.timestamp),
-								version: existing.version + 1
+								version: 1
 							})
-							.where(eq(notes.id, change.noteId));
+							.run();
 					}
-				} else if (change.operation === 'create' && change.data) {
-					await db.insert(notes).values({
-						id: change.noteId,
-						title: change.data.title || '',
-						content: change.data.content || '',
-						color: change.data.color || 'default',
-						pinned: change.data.pinned || false,
-						archived: change.data.archived || false,
-						trashed: change.data.trashed || false,
-						checklistMode: change.data.checklistMode || false,
-						sortOrder: change.data.sortOrder || 0,
-						createdAt: new Date(change.timestamp),
-						updatedAt: new Date(change.timestamp),
-						version: 1
-					});
+					break;
+				}
+				case 'delete': {
+					tx.delete(notes).where(eq(notes.id, change.noteId)).run();
+					break;
 				}
-				break;
 			}
-			case 'delete': {
-				await db.delete(notes).where(eq(notes.id, change.noteId));
-				break;
-			}
-		}
 
-		// Log sync operation
-		await db.insert(syncLog).values({
-			noteId: change.noteId,
-			operation: change.operation,
-			timestamp: new Date(change.timestamp),
-			clientId: 'default'
-		});
-	}
+			tx.insert(syncLog)
+				.values({
+					noteId: change.noteId,
+					operation: change.operation,
+					timestamp: new Date(change.timestamp),
+					clientId: 'default'
+				})
+				.run();
+		}
+	});
 }
 
 /**
  * Get all notes updated since a given timestamp.
  */
 export async function getChangesSince(sinceTimestamp: number) {
-	const since = new Date(sinceTimestamp);
-	const allNotes = await db.select().from(notes);
-	// Filter notes updated after the timestamp
-	return allNotes.filter((n) => n.updatedAt > since);
+	return db
+		.select()
+		.from(notes)
+		.where(gt(notes.updatedAt, new Date(sinceTimestamp)))
+		.all();
 }

src/routes/+error.svelte

@@ -0,0 +1,25 @@
+<script lang="ts">
+	import { page } from '$app/state';
+</script>
+
+<svelte:head>
+	<title>Error - Crumbs</title>
+</svelte:head>
+
+<div class="flex min-h-screen items-center justify-center bg-[var(--bg-base)]">
+	<div class="w-full max-w-sm rounded-sm border border-[var(--border)] bg-[var(--bg-surface)] p-8 text-center">
+		<span class="text-5xl">🥨</span>
+		<h1 class="mt-4 font-['Press_Start_2P'] text-xl text-[var(--primary)]">
+			{page.status}
+		</h1>
+		<p class="mt-4 text-sm text-[var(--text-muted)]">
+			{page.error?.message ?? 'Something went wrong'}
+		</p>
+		<a
+			href="/"
+			class="mt-6 inline-block rounded-sm bg-[var(--primary)] px-6 py-2 text-sm font-medium text-white transition-colors hover:bg-[var(--primary-hover)]"
+		>
+			Back to notes
+		</a>
+	</div>
+</div>

src/routes/api/notes/+server.ts

@@ -1,10 +1,11 @@
 import { json } from '@sveltejs/kit';
 import type { RequestHandler } from './$types.js';
 import { db } from '$lib/server/db/index.js';
-import { notes, noteTags, tags } from '$lib/server/db/schema.js';
+import { notes } from '$lib/server/db/schema.js';
 import { eq, and, desc } from 'drizzle-orm';
 import { v4 as uuidv4 } from 'uuid';
 import { extractTags } from '$lib/utils/tags.js';
+import { fetchTagsForNotes, syncNoteTags } from '$lib/server/tags.js';
 
 export const GET: RequestHandler = async ({ url }) => {
 	const filter = url.searchParams.get('filter') || 'all';
@@ -21,23 +22,18 @@ export const GET: RequestHandler = async ({ url }) => {
 			conditions = and(eq(notes.archived, false), eq(notes.trashed, false));
 	}
 
-	const result = await db
+	const result = db
 		.select()
 		.from(notes)
 		.where(conditions)
-		.orderBy(desc(notes.pinned), desc(notes.updatedAt));
+		.orderBy(desc(notes.pinned), desc(notes.updatedAt))
+		.all();
 
-	// Fetch tags for each note
-	const notesWithTags = await Promise.all(
-		result.map(async (note) => {
-			const tagRows = await db
-				.select({ name: tags.name })
-				.from(noteTags)
-				.innerJoin(tags, eq(noteTags.tagId, tags.id))
-				.where(eq(noteTags.noteId, note.id));
-			return { ...note, tags: tagRows.map((t) => t.name) };
-		})
-	);
+	const tagMap = fetchTagsForNotes(result.map((n) => n.id));
+	const notesWithTags = result.map((note) => ({
+		...note,
+		tags: tagMap.get(note.id) ?? []
+	}));
 
 	return json(notesWithTags);
 };
@@ -63,27 +59,13 @@ export const POST: RequestHandler = async ({ request }) => {
 		version: 1
 	};
 
-	await db.insert(notes).values(newNote);
-
-	// Extract and save tags
 	const content = `${newNote.title} ${newNote.content}`;
 	const extractedTags = extractTags(content);
-	await syncNoteTags(id, extractedTags);
+
+	db.transaction((tx) => {
+		tx.insert(notes).values(newNote).run();
+	});
+	syncNoteTags(id, extractedTags);
 
 	return json({ ...newNote, tags: extractedTags }, { status: 201 });
 };
-
-async function syncNoteTags(noteId: string, tagNames: string[]) {
-	// Remove existing tag associations
-	await db.delete(noteTags).where(eq(noteTags.noteId, noteId));
-
-	for (const name of tagNames) {
-		// Upsert tag
-		let tagRow = await db.select().from(tags).where(eq(tags.name, name)).get();
-		if (!tagRow) {
-			const result = await db.insert(tags).values({ name }).returning();
-			tagRow = result[0];
-		}
-		await db.insert(noteTags).values({ noteId, tagId: tagRow.id });
-	}
-}

src/routes/api/notes/[id]/+server.ts

@@ -1,29 +1,26 @@
 import { json, error } from '@sveltejs/kit';
 import type { RequestHandler } from './$types.js';
 import { db } from '$lib/server/db/index.js';
-import { notes, noteTags, tags } from '$lib/server/db/schema.js';
+import { notes } from '$lib/server/db/schema.js';
 import { eq } from 'drizzle-orm';
 import { extractTags } from '$lib/utils/tags.js';
+import { fetchTagsForNotes, syncNoteTags } from '$lib/server/tags.js';
 
 export const GET: RequestHandler = async ({ params }) => {
-	const note = await db.select().from(notes).where(eq(notes.id, params.id)).get();
+	const note = db.select().from(notes).where(eq(notes.id, params.id)).get();
 
 	if (!note) {
 		throw error(404, 'Note not found');
 	}
 
-	const tagRows = await db
-		.select({ name: tags.name })
-		.from(noteTags)
-		.innerJoin(tags, eq(noteTags.tagId, tags.id))
-		.where(eq(noteTags.noteId, note.id));
+	const tagMap = fetchTagsForNotes([note.id]);
 
-	return json({ ...note, tags: tagRows.map((t) => t.name) });
+	return json({ ...note, tags: tagMap.get(note.id) ?? [] });
 };
 
 export const PATCH: RequestHandler = async ({ params, request }) => {
 	const body = await request.json();
-	const existing = await db.select().from(notes).where(eq(notes.id, params.id)).get();
+	const existing = db.select().from(notes).where(eq(notes.id, params.id)).get();
 
 	if (!existing) {
 		throw error(404, 'Note not found');
@@ -47,46 +44,28 @@ export const PATCH: RequestHandler = async ({ params, request }) => {
 	if (body.checklistMode !== undefined) updates.checklistMode = body.checklistMode;
 	if (body.sortOrder !== undefined) updates.sortOrder = body.sortOrder;
 
-	await db.update(notes).set(updates).where(eq(notes.id, params.id));
+	db.update(notes).set(updates).where(eq(notes.id, params.id)).run();
 
-	const updated = await db.select().from(notes).where(eq(notes.id, params.id)).get();
+	const updated = db.select().from(notes).where(eq(notes.id, params.id)).get();
 
-	// Re-sync tags if content or title changed
 	if (body.title !== undefined || body.content !== undefined) {
 		const content = `${updated!.title} ${updated!.content}`;
 		const extractedTags = extractTags(content);
-		await syncNoteTags(params.id, extractedTags);
+		syncNoteTags(params.id, extractedTags);
 	}
 
-	const tagRows = await db
-		.select({ name: tags.name })
-		.from(noteTags)
-		.innerJoin(tags, eq(noteTags.tagId, tags.id))
-		.where(eq(noteTags.noteId, params.id));
+	const tagMap = fetchTagsForNotes([params.id]);
 
-	return json({ ...updated, tags: tagRows.map((t) => t.name) });
+	return json({ ...updated, tags: tagMap.get(params.id) ?? [] });
 };
 
 export const DELETE: RequestHandler = async ({ params }) => {
-	const existing = await db.select().from(notes).where(eq(notes.id, params.id)).get();
+	const existing = db.select().from(notes).where(eq(notes.id, params.id)).get();
 
 	if (!existing) {
 		throw error(404, 'Note not found');
 	}
 
-	await db.delete(notes).where(eq(notes.id, params.id));
+	db.delete(notes).where(eq(notes.id, params.id)).run();
 	return json({ success: true });
 };
-
-async function syncNoteTags(noteId: string, tagNames: string[]) {
-	await db.delete(noteTags).where(eq(noteTags.noteId, noteId));
-
-	for (const name of tagNames) {
-		let tagRow = await db.select().from(tags).where(eq(tags.name, name)).get();
-		if (!tagRow) {
-			const result = await db.insert(tags).values({ name }).returning();
-			tagRow = result[0];
-		}
-		await db.insert(noteTags).values({ noteId, tagId: tagRow.id });
-	}
-}

src/routes/api/search/+server.ts

@@ -2,7 +2,8 @@ import { json } from '@sveltejs/kit';
 import type { RequestHandler } from './$types.js';
 import { db } from '$lib/server/db/index.js';
 import { notes, noteTags, tags } from '$lib/server/db/schema.js';
-import { and, eq, like, or } from 'drizzle-orm';
+import { and, eq, like, or, inArray } from 'drizzle-orm';
+import { fetchTagsForNotes } from '$lib/server/tags.js';
 
 export const GET: RequestHandler = async ({ url }) => {
 	const query = url.searchParams.get('q')?.trim();
@@ -13,7 +14,7 @@ export const GET: RequestHandler = async ({ url }) => {
 
 	const pattern = `%${query}%`;
 
-	const results = await db
+	const results = db
 		.select()
 		.from(notes)
 		.where(
@@ -21,45 +22,37 @@ export const GET: RequestHandler = async ({ url }) => {
 				eq(notes.trashed, false),
 				or(like(notes.title, pattern), like(notes.content, pattern))
 			)
-		);
+		)
+		.all();
 
 	// Also search by tag name
-	const tagResults = await db
+	const tagResults = db
 		.select({ noteId: noteTags.noteId })
 		.from(noteTags)
 		.innerJoin(tags, eq(noteTags.tagId, tags.id))
-		.where(like(tags.name, pattern));
+		.where(like(tags.name, pattern))
+		.all();
 
-	const tagNoteIds = new Set(tagResults.map((r) => r.noteId));
-	const allNoteIds = new Set(results.map((n) => n.id));
+	const resultIds = new Set(results.map((n) => n.id));
+	const extraNoteIds = [...new Set(tagResults.map((r) => r.noteId))].filter(
+		(id) => !resultIds.has(id)
+	);
 
-	// Fetch tag-matched notes not already in results
-	const extraNoteIds = [...tagNoteIds].filter((id) => !allNoteIds.has(id));
 	let extraNotes: typeof results = [];
 	if (extraNoteIds.length > 0) {
-		for (const id of extraNoteIds) {
-			const note = await db
-				.select()
-				.from(notes)
-				.where(and(eq(notes.id, id), eq(notes.trashed, false)))
-				.get();
-			if (note) extraNotes.push(note);
-		}
+		extraNotes = db
+			.select()
+			.from(notes)
+			.where(and(inArray(notes.id, extraNoteIds), eq(notes.trashed, false)))
+			.all();
 	}
 
 	const combined = [...results, ...extraNotes];
-
-	// Attach tags to each note
-	const withTags = await Promise.all(
-		combined.map(async (note) => {
-			const tagRows = await db
-				.select({ name: tags.name })
-				.from(noteTags)
-				.innerJoin(tags, eq(noteTags.tagId, tags.id))
-				.where(eq(noteTags.noteId, note.id));
-			return { ...note, tags: tagRows.map((t) => t.name) };
-		})
-	);
+	const tagMap = fetchTagsForNotes(combined.map((n) => n.id));
+	const withTags = combined.map((note) => ({
+		...note,
+		tags: tagMap.get(note.id) ?? []
+	}));
 
 	return json(withTags);
 };