perf: Optimize packages endpoint - reduce from N*3 queries to 3 batch queries

- Replace individual queries per package with batch GROUP BY queries
- Reduces from potentially hundreds of queries to just 3 queries total
- Creates lookup maps for O(1) access when assembling results
- Improves packages page loading time significantly

backend/src/routes/packageRoutes.js

@@ -101,37 +101,41 @@ router.get("/", async (req, res) => {
 			prisma.packages.count({ where }),
 		]);
 
-		// Get additional stats for each package
-		const packagesWithStats = await Promise.all(
-			packages.map(async (pkg) => {
-				// Build base where clause for this package
-				const baseWhere = { package_id: pkg.id };
+		// OPTIMIZATION: Batch query all stats instead of N individual queries
+		const packageIds = packages.map((pkg) => pkg.id);
 
-				// If host filter is specified, add host filter to all queries
-				const hostWhere = host ? { ...baseWhere, host_id: host } : baseWhere;
-
-				const [updatesCount, securityCount, packageHosts] = await Promise.all([
-					prisma.host_packages.count({
+		// Get all counts and host data in 3 batch queries instead of N*3 queries
+		const [allUpdatesCounts, allSecurityCounts, allPackageHostsData] =
+			await Promise.all([
+				// Batch count all packages that need updates
+				prisma.host_packages.groupBy({
+					by: ["package_id"],
 					where: {
-							...hostWhere,
+						package_id: { in: packageIds },
 						needs_update: true,
+						...(host ? { host_id: host } : {}),
 					},
+					_count: { id: true },
 				}),
-					prisma.host_packages.count({
+				// Batch count all packages with security updates
+				prisma.host_packages.groupBy({
+					by: ["package_id"],
 					where: {
-							...hostWhere,
+						package_id: { in: packageIds },
 						needs_update: true,
 						is_security_update: true,
+						...(host ? { host_id: host } : {}),
 					},
+					_count: { id: true },
 				}),
+				// Batch fetch all host data for packages
 				prisma.host_packages.findMany({
 					where: {
-							...hostWhere,
-							// If host filter is specified, include all packages for that host
-							// Otherwise, only include packages that need updates
-							...(host ? {} : { needs_update: true }),
+						package_id: { in: packageIds },
+						...(host ? { host_id: host } : { needs_update: true }),
 					},
 					select: {
+						package_id: true,
 						hosts: {
 							select: {
 								id: true,
@@ -145,14 +149,27 @@ router.get("/", async (req, res) => {
 						needs_update: true,
 						is_security_update: true,
 					},
-						take: 10, // Limit to first 10 for performance
+					// Limit to first 10 per package
+					take: 100, // Increased from package-based limit
 				}),
 			]);
 
-				return {
-					...pkg,
-					packageHostsCount: pkg._count.host_packages,
-					packageHosts: packageHosts.map((hp) => ({
+		// Create lookup maps for O(1) access
+		const updatesCountMap = new Map(
+			allUpdatesCounts.map((item) => [item.package_id, item._count.id]),
+		);
+		const securityCountMap = new Map(
+			allSecurityCounts.map((item) => [item.package_id, item._count.id]),
+		);
+		const packageHostsMap = new Map();
+
+		// Group host data by package_id
+		for (const hp of allPackageHostsData) {
+			if (!packageHostsMap.has(hp.package_id)) {
+				packageHostsMap.set(hp.package_id, []);
+			}
+			const hosts = packageHostsMap.get(hp.package_id);
+			hosts.push({
 				hostId: hp.hosts.id,
 				friendlyName: hp.hosts.friendly_name,
 				osType: hp.hosts.os_type,
@@ -160,15 +177,31 @@ router.get("/", async (req, res) => {
 				availableVersion: hp.available_version,
 				needsUpdate: hp.needs_update,
 				isSecurityUpdate: hp.is_security_update,
-					})),
+			});
+
+			// Limit to 10 hosts per package
+			if (hosts.length > 10) {
+				packageHostsMap.set(hp.package_id, hosts.slice(0, 10));
+			}
+		}
+
+		// Map packages with stats from lookup maps (no more DB queries!)
+		const packagesWithStats = packages.map((pkg) => {
+			const updatesCount = updatesCountMap.get(pkg.id) || 0;
+			const securityCount = securityCountMap.get(pkg.id) || 0;
+			const packageHosts = packageHostsMap.get(pkg.id) || [];
+
+			return {
+				...pkg,
+				packageHostsCount: pkg._count.host_packages,
+				packageHosts,
 				stats: {
 					totalInstalls: pkg._count.host_packages,
 					updatesNeeded: updatesCount,
 					securityUpdates: securityCount,
 				},
 			};
-			}),
-		);
+		});
 
 		res.json({
 			packages: packagesWithStats,