From ba64ea9528f7007915359d70b49ddea80ec0603b Mon Sep 17 00:00:00 2001
From: seonghobae <8172694+seonghobae@users.noreply.github.com>
Date: Sun, 7 Jun 2026 21:34:27 +0000
Subject: [PATCH] perf(web): replace multiple reduce calls with single loops

Replaced chained `.reduce()` passes over Prisma relationship arrays (`session.usageRecords`) with single `for...of` loops in session-related API routes to improve iteration performance and reduce CPU cycles.
---
 .jules/bolt.md                                |  4 ++++
 .../dashboard/sessions/[sessionId]/route.ts   | 13 +++++++++---
 .../[orgSlug]/dashboard/sessions/route.ts     | 20 +++++++++++++------
 3 files changed, 28 insertions(+), 9 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..7c6add9
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,4 @@
+
+## 2024-05-18 - Single Loop Over Prisma Relations
+**Learning:** When processing large datasets from Prisma `include` blocks, multiple iteration passes (like chained `.reduce()` calls) over the in-memory relations add unnecessary iteration overhead and can cause performance bottlenecks.
+**Action:** Avoid chaining array methods (`.map()`, `.reduce()`, `.filter()`) on large datasets fetched via Prisma. Prefer a single loop (like a `for...of` loop) to calculate multiple derived values simultaneously.
diff --git a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts
index 35486b8..0344d6b 100644
--- a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts
+++ b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts
@@ -43,9 +43,16 @@ export async function GET(
       return forbiddenByRole(access.role, '본인 세션만 열람 가능')
     }
 
-    const totalInput = session.usageRecords.reduce((sum, r) => sum + r.inputTokens, 0)
-    const totalOutput = session.usageRecords.reduce((sum, r) => sum + r.outputTokens, 0)
-    const totalCost = session.usageRecords.reduce((sum, r) => sum + (r.estimatedCostUsd ?? 0), 0)
+    // ⚡ Bolt: Use a single loop to calculate totals, avoiding 3 iteration passes over the array.
+    let totalInput = 0
+    let totalOutput = 0
+    let totalCost = 0
+
+    for (const r of session.usageRecords) {
+      totalInput += r.inputTokens
+      totalOutput += r.outputTokens
+      totalCost += r.estimatedCostUsd ?? 0
+    }
 
     const usageTimeline: SessionTimelineUsage[] = session.usageRecords.map((r) => ({
       timestamp: r.timestamp.toISOString(),
diff --git a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
index 25fbe70..4df0663 100644
--- a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
+++ b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
@@ -33,13 +33,21 @@ const sessionInclude = {
 type SessionWithInclude = Prisma.ClaudeSessionGetPayload<{ include: typeof sessionInclude }>
 
 function getSessionTotals(session: SessionWithInclude) {
+  // ⚡ Bolt: Use a single loop to calculate totals, avoiding 3 iteration passes over the array.
+  let inputTokens = 0
+  let outputTokens = 0
+  let estimatedCostUsd = 0
+
+  for (const r of session.usageRecords) {
+    inputTokens += r.inputTokens
+    outputTokens += r.outputTokens
+    estimatedCostUsd += r.estimatedCostUsd ?? 0
+  }
+
   return {
-    inputTokens: session.usageRecords.reduce((sum, r) => sum + r.inputTokens, 0),
-    outputTokens: session.usageRecords.reduce((sum, r) => sum + r.outputTokens, 0),
-    estimatedCostUsd: session.usageRecords.reduce(
-      (sum, r) => sum + (r.estimatedCostUsd ?? 0),
-      0,
-    ),
+    inputTokens,
+    outputTokens,
+    estimatedCostUsd,
   }
 }