⚡ Bolt: Resolve sequential DB query waterfalls in entity GET routes

.jules/bolt.md

@@ -5,3 +5,7 @@
 ## 2024-05-18 - Concurrent Fetching with Owner IDs in Share Links
 **Learning:** In the share system, endpoints processing a share code typically suffer from waterfall latency by first loading target entity details (like a project) and then querying its associated elements (like project lists) using the entity's owner ID (`userId`). However, the `shareLink` object already contains the `userId` field (representing the owner's ID).
 **Action:** Always leverage the existing owner's ID within `shareLink` to bypass sequential dependencies and fetch parent entities (like projects) concurrently with their child elements (like user lists) using `Promise.all`.
+
+## 2024-05-23 - Concurrent Parent/Child Data Fetching in API Routes
+**Learning:** In backend API routes (e.g. GET requests for entities), sequentially awaiting a parent validation query (like `getProject(userId, projectId)`) and then its child data query (`getProjectLists(userId, projectId)`) creates a database query waterfall that adds unnecessary latency.
+**Action:** When the child query does not strictly depend on the result of the parent query (for example, when both rely on existing parameters like `userId` and `projectId`/`listId`), execute both queries concurrently using `Promise.all` and then perform the necessary validation checks (e.g. `if (!project) return 404`).

src/app/api/lists/[id]/citations/[citationId]/route.ts

@@ -21,16 +21,19 @@ export async function GET(request: NextRequest, { params }: RouteParams) {
     }
 
     // Verify the list exists and belongs to the user
-    const list = await getList(userId, listId);
+    // Fetch list details and citation concurrently by utilizing the userId
+    const [list, citation] = await Promise.all([
+      getList(userId, listId),
+      getCitation(listId, citationId),
+    ]);
+
     if (!list) {
       return NextResponse.json(
         { success: false, error: "List not found" },
         { status: 404 }
       );
     }
 
-    const citation = await getCitation(listId, citationId);
-
     if (!citation) {
       return NextResponse.json(
         { success: false, error: "Citation not found" },

src/app/api/lists/[id]/citations/route.ts

@@ -22,16 +22,19 @@ export async function GET(request: NextRequest, { params }: RouteParams) {
     }
 
     // Verify the list exists and belongs to the user
-    const list = await getList(userId, listId);
+    // Fetch list details and list citations concurrently by utilizing the userId
+    const [list, citations] = await Promise.all([
+      getList(userId, listId),
+      getListCitations(listId),
+    ]);
+
     if (!list) {
       return NextResponse.json(
         { success: false, error: "List not found" },
         { status: 404 }
       );
     }
 
-    const citations = await getListCitations(listId);
-
     return NextResponse.json({
       success: true,
       data: citations,

src/app/api/projects/[id]/lists/route.ts

@@ -21,16 +21,19 @@ export async function GET(request: NextRequest, { params }: RouteParams) {
     }
 
     // Verify the project exists and belongs to the user
-    const project = await getProject(userId, projectId);
+    // Fetch project details and user lists concurrently by utilizing the userId
+    const [project, lists] = await Promise.all([
+      getProject(userId, projectId),
+      getProjectLists(userId, projectId),
+    ]);
+
     if (!project) {
       return NextResponse.json(
         { success: false, error: "Project not found" },
         { status: 404 }
       );
     }
 
-    const lists = await getProjectLists(userId, projectId);
-
     return NextResponse.json({
       success: true,
       data: lists,