diff --git a/lib/db.ts b/lib/db.ts
index 1e01984..32aee1b 100644
--- a/lib/db.ts
+++ b/lib/db.ts
@@ -1,3 +1,5 @@
+import { writeSync } from "fs";
+
 import { PrismaMariaDb } from "@prisma/adapter-mariadb";
 import { format } from "sql-formatter";
 
@@ -46,12 +48,8 @@ function onQuery(e: Prisma.QueryEvent): void {
     .map((l) => `  ${l}`)
     .join("\n");
 
-  const out = `${header}\n${indented}`;
-  if (isSlow) {
-    console.error(out);
-  } else {
-    console.log(out);
-  }
+  const out = `${header}\n${indented}\n`;
+  writeSync(isSlow ? 2 : 1, out);
 }
 
 // ── 결과 로깅 ($extends) ──────────────────────────────────────────
@@ -198,7 +196,7 @@ function logResult(
   if (!logger.isEnabled("debug")) return;
   const ts = new Date().toISOString();
   const body = buildResultLog(model, operation, result);
-  console.log(`[${ts}] [DEBUG] [db:result] ${body}`);
+  writeSync(1, `[${ts}] [DEBUG] [db:result] ${body}\n`);
 }
 
 // ── PrismaClient 생성 ─────────────────────────────────────────────