diff --git a/lib/db.ts b/lib/db.ts
index 32aee1b..55d7bb9 100644
--- a/lib/db.ts
+++ b/lib/db.ts
@@ -12,6 +12,21 @@ const globalForPrisma = globalThis as unknown as {
 
 const SLOW_QUERY_MS = Number(process.env.DB_SLOW_QUERY_MS ?? "1000");
 
+// Docker 파이프 환경에서 stdout fd는 non-blocking이라 writeSync가 부분 쓰기를
+// 하거나 EAGAIN을 던질 수 있다. 전부 쓸 때까지 반복해 로그 유실을 막는다.
+function writeAll(fd: number, text: string): void {
+  const buf = Buffer.from(text, "utf8");
+  let offset = 0;
+  while (offset < buf.length) {
+    try {
+      offset += writeSync(fd, buf, offset, buf.length - offset);
+    } catch (err) {
+      if ((err as NodeJS.ErrnoException).code === "EAGAIN") continue;
+      throw err;
+    }
+  }
+}
+
 // ── SQL 로깅 ($on) ────────────────────────────────────────────────
 
 function inlineParams(query: string, rawParams: string): string {
@@ -49,7 +64,7 @@ function onQuery(e: Prisma.QueryEvent): void {
     .join("\n");
 
   const out = `${header}\n${indented}\n`;
-  writeSync(isSlow ? 2 : 1, out);
+  writeAll(isSlow ? 2 : 1, out);
 }
 
 // ── 결과 로깅 ($extends) ──────────────────────────────────────────
@@ -196,7 +211,7 @@ function logResult(
   if (!logger.isEnabled("debug")) return;
   const ts = new Date().toISOString();
   const body = buildResultLog(model, operation, result);
-  writeSync(1, `[${ts}] [DEBUG] [db:result] ${body}\n`);
+  writeAll(1, `[${ts}] [DEBUG] [db:result] ${body}\n`);
 }
 
 // ── PrismaClient 생성 ─────────────────────────────────────────────