From 7027b78f7a775ff3f6ef9f6f4e692604e9338be9 Mon Sep 17 00:00:00 2001
From: seonghobae <8172694+seonghobae@users.noreply.github.com>
Date: Mon, 8 Jun 2026 21:16:44 +0000
Subject: [PATCH] perf(web): optimize usage records aggregation to single pass

Combined three separate `.reduce()` calls into a single `for...of` loop
when aggregating `inputTokens`, `outputTokens`, and `estimatedCostUsd`
over `session.usageRecords`. This reduces the iteration time complexity
from O(3N) to O(N), which minimizes iteration overhead and memory bottlenecks
for large datasets returned from Prisma include blocks.
---
 .jules/bolt.md                                |  0
 .../dashboard/sessions/[sessionId]/route.ts   | 13 +++++++++---
 .../[orgSlug]/dashboard/sessions/route.ts     | 21 +++++++++++++------
 3 files changed, 25 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..e69de29
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..28c4229 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)
+    // Performance Optimization: Combine 3 reduce calls into a single loop to avoid multiple iterations
+    // over potentially large usageRecords datasets.
+    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..297e14c 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 +33,22 @@ const sessionInclude = {
 type SessionWithInclude = Prisma.ClaudeSessionGetPayload<{ include: typeof sessionInclude }>
 
 function getSessionTotals(session: SessionWithInclude) {
+  // Performance Optimization: Combine 3 reduce calls into a single loop to avoid multiple iterations
+  // over potentially large usageRecords datasets.
+  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,
   }
 }