服务器发生错误时所提供的唯一错误码，打印在 Proxy 后端或 JDBC 启动日志中。
| 错误码 | 错误信息 |
|---|---|
| SPI-00001 | No implementation class load from SPI ‘%s’ with type ‘%s’. |
| DATA-SOURCE-00001 | Data source ‘%s’ is unavailable. |
| PROPS-00001 | Properties convert failed, details are: %s. |
| PROXY-00001 | Load database server info failed. |