# rpc 错误：code = ResourceExhausted desc = grpc：接收到的消息大于最大值（5242881 vs. 4194304）

- **ID:** `go/grpc-resource-exhausted-msg-size`
- **领域:** go
- **类别:** resource_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

消息超过了默认的 4MB gRPC 接收限制。服务器发送的载荷大于客户端的 MaxCallRecvMsgSize（或反之）。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| grpc-go 1.55+ | active | — | — |

## 解决方案

1. **** (90% 成功率)
   ```
   Raise both send and receive limits on client and server:
// client
conn, err := grpc.NewClient(addr,
    grpc.WithDefaultCallOptions(
        grpc.MaxCallRecvMsgSize(16*1024*1024),
        grpc.MaxCallSendMsgSize(16*1024*1024),
    ),
)
// server
srv := grpc.NewServer(grpc.MaxRecvMsgSize(16*1024*1024), grpc.MaxSendMsgSize(16*1024*1024))
   ```
2. **** (85% 成功率)
   ```
   Switch large payloads to gRPC streaming so messages are chunked:
stream, err := client.Upload(ctx)
for _, chunk := range chunks {
    if err := stream.Send(&pb.Chunk{Data: chunk}); err != nil { return err }
}
return stream.CloseAndRecv()
   ```

## 无效尝试

- **** — The message size is deterministic; retrying sends the same oversized payload and fails identically every time. (95% 失败率)
- **** — The send side also enforces MaxCallSendMsgSize; if the server sends a large response, only the receive limit matters, but large requests fail on the server's recv limit. (70% 失败率)