503 Service Unavailable

Perha ps your MySQL server is down, so your API is temporarily bored. . . send a 503 (Service unavailable).

又或者你的MySQL服务器挂了，接口也会临时性的中断，发送一个503错误（服务不可用）。

All new requests will be returned immediately with HTTP 503 (Service unavailable) error messages until the pending requests are processed.

在处理完挂起的请求前，将连同HTTP503（服务不可用）错误消息立即返回所有新的请求。

503 Service Unavailable The request was not completed. The server is temporarily overloading or down. Experimental Investigation on Ultimate Load-Bearing Capacity of PBL Shear Connectors

请求未能完成。服务器承载量超负荷。PBL传剪器极限承载力的试验研究

As you can see, del. icio. us was returning an HTTP 503 (Service Unavailable status code).

正如您所见，del.icio.us返回了HTTP503（服务不可用状态代码）。