我已经使用 ClearDb mysql 在heroku 上部署了一个nodejs 应用程序，该应用程序工作了一会儿然后崩溃了。我检查了日志并得到了这个错误
2019-09-20T19:03:41.536452+00:00 app[web.1]: events.js:174
2019-09-20T19:03:41.536474+00:00 app[web.1]: throw er; // Unhandled 'error' event
2019-09-20T19:03:41.536476+00:00 app[web.1]: ^
2019-09-20T19:03:41.536478+00:00 app[web.1]:
2019-09-20T19:03:41.536481+00:00 app[web.1]: Error: Connection lost: The server closed the connection.
2019-09-20T19:03:41.536483+00:00 app[web.1]: at Protocol.end (/app/node_modules/mysql/lib/protocol/Protocol.js:112:13)
2019-09-20T19:03:41.536485+00:00 app[web.1]: at Socket.<anonymous> (/app/node_modules/mysql/lib/Connection.js:97:28)
2019-09-20T19:03:41.536488+00:00 app[web.1]: at Socket.<anonymous> (/app/node_modules/mysql/lib/Connection.js:525:10)
2019-09-20T19:03:41.53649+00:00 app[web.1]: at Socket.emit (events.js:203:15)
2019-09-20T19:03:41.536492+00:00 app[web.1]: at endReadableNT (_stream_readable.js:1145:12)
2019-09-20T19:03:41.536495+00:00 app[web.1]: at process._tickCallback (internal/process/next_tick.js:63:19)
2019-09-20T19:03:41.536497+00:00 app[web.1]: Emitted 'error' event at:
2019-09-20T19:03:41.536503+00:00 app[web.1]: at Connection._handleProtocolError (/app/node_modules/mysql/lib/Connection.js:426:8)
2019-09-20T19:03:41.536506+00:00 app[web.1]: at Protocol.emit (events.js:198:13)
2019-09-20T19:03:41.536509+00:00 app[web.1]: …