From 99bfbb59d0c8fcf2c23506c63cf33fa2e39cd976 Mon Sep 17 00:00:00 2001
From: seonghobae <8172694+seonghobae@users.noreply.github.com>
Date: Wed, 3 Jun 2026 21:34:26 +0000
Subject: [PATCH] perf(web): optimize Prisma relation iterations

Replaced chained `.reduce()` calls over large `usageRecords` relation arrays with single-pass `for...of` loops in dashboard session endpoints. This eliminates multiple iteration passes and reduces CPU overhead when processing large relation payloads from the database.
---
 .jules/bolt.md                                |  3 +++
 .../dashboard/sessions/[sessionId]/route.ts   | 11 ++++++++---
 .../[orgSlug]/dashboard/sessions/route.ts     | 19 +++++++++++++------
 3 files changed, 24 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..cbc4772
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2024-06-03 - [Optimize Prisma Relations Iteration]
+**Learning:** When processing large datasets from Prisma `include` blocks, chained `.reduce()` or `.map()` calls can introduce unnecessary iteration passes over the same relation data in memory, increasing CPU overhead.
+**Action:** Replace multiple chained iterations over the same arrays with a single `for...of` loop to calculate all required aggregates 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..63b1420 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 +43,14 @@ 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)
+    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..5de4e22 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 +33,20 @@ const sessionInclude = {
 type SessionWithInclude = Prisma.ClaudeSessionGetPayload<{ include: typeof sessionInclude }>
 
 function getSessionTotals(session: SessionWithInclude) {
+  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,
   }
 }