⚡ Bolt: Parallelize independent sequential database queries

.jules/bolt.md

@@ -0,0 +1,3 @@
+## 2024-06-25 - Parallelize Independent Sequential Drizzle Queries
+**Learning:** Found multiple instances where independent database queries (like paginated fetches alongside total count queries, or multiple aggregate queries for a dashboard) were being awaited sequentially using `await db.select(...)`. In this Next.js Drizzle architecture, this creates an unnecessary waterfall of requests, increasing latency.
+**Action:** When interacting with the database via Drizzle ORM, parallelize independent sequential queries using `Promise.all([db.select(...), db.select(...)])` to minimize overall request latency.

app/api/products/route.ts

@@ -58,19 +58,20 @@ export async function GET(req: NextRequest) {
       conditions.push(eq(products.isFeatured, true));
     }
 
-    const result = await db
-      .select()
-      .from(products)
-      .where(and(...conditions))
-      .orderBy(desc(products.displayOrder), desc(products.createdAt))
-      .limit(limit)
-      .offset(offset);
-
-    // Get total count for pagination
-    const [{ count }] = await db
-      .select({ count: sql<number>`count(*)` })
-      .from(products)
-      .where(and(...conditions));
+    // Parallelize data fetch and total count queries to reduce latency
+    const [result, [{ count }]] = await Promise.all([
+      db
+        .select()
+        .from(products)
+        .where(and(...conditions))
+        .orderBy(desc(products.displayOrder), desc(products.createdAt))
+        .limit(limit)
+        .offset(offset),
+      db
+        .select({ count: sql<number>`count(*)` })
+        .from(products)
+        .where(and(...conditions))
+    ]);
 
     return NextResponse.json({
       products: result,

lib/actions/admin.ts

@@ -506,34 +506,35 @@ export async function getDashboardStats() {
   const now = new Date();
   const thirtyDaysAgo = new Date(now.getTime() - 30 * 24 * 60 * 60 * 1000);
 
-  // Total products
-  const [{ count: totalProducts }] = await db
-    .select({ count: sql<number>`count(*)` })
-    .from(products)
-    .where(eq(products.isActive, true));
-
-  // Total orders (last 30 days)
-  const [{ count: totalOrders }] = await db
-    .select({ count: sql<number>`count(*)` })
-    .from(orders)
-    .where(gte(orders.createdAt, thirtyDaysAgo));
-
-  // Total revenue (last 30 days)
-  const [{ sum: totalRevenue }] = await db
-    .select({ sum: sql<string>`COALESCE(sum(total), 0)` })
-    .from(orders)
-    .where(
-      and(
-        gte(orders.createdAt, thirtyDaysAgo),
-        eq(orders.status, "delivered")
-      )
-    );
-
-  // Active coupons
-  const [{ count: activeCoupons }] = await db
-    .select({ count: sql<number>`count(*)` })
-    .from(coupons)
-    .where(eq(coupons.isActive, true));
+  // Run independent sequential queries concurrently to avoid waterfall requests
+  const [
+    [{ count: totalProducts }],
+    [{ count: totalOrders }],
+    [{ sum: totalRevenue }],
+    [{ count: activeCoupons }]
+  ] = await Promise.all([
+    db
+      .select({ count: sql<number>`count(*)` })
+      .from(products)
+      .where(eq(products.isActive, true)),
+    db
+      .select({ count: sql<number>`count(*)` })
+      .from(orders)
+      .where(gte(orders.createdAt, thirtyDaysAgo)),
+    db
+      .select({ sum: sql<string>`COALESCE(sum(total), 0)` })
+      .from(orders)
+      .where(
+        and(
+          gte(orders.createdAt, thirtyDaysAgo),
+          eq(orders.status, "delivered")
+        )
+      ),
+    db
+      .select({ count: sql<number>`count(*)` })
+      .from(coupons)
+      .where(eq(coupons.isActive, true))
+  ]);
 
   return {
     totalProducts: Number(totalProducts),