我的nodejs web服務正在關閉，出現這些錯誤

Question

這個錯誤發生在我的web服務連續運行8到10個小時後，連續運行永久模塊。

{ 
    "date": "Wed Sep 13 2017 21:22:25 GMT+0000 (UTC)", 
    "process": { 
     "pid": 24337, 
     "uid": 1000, 
     "gid": 1000, 
     "cwd": "/path/to/my/file/", 
     "execPath": "/path/to/my/nvm/.nvm/versions/node/v4.4.5/bin/node", 
     "version": "v4.4.5", 
     "argv": ["/path/to/my/nvm/.nvm/versions/node/v4.4.5/bin/node", "/path/to/my/file/app.js"], 
     "memoryUsage": { 
      "rss": 133083136, 
      "heapTotal": 83753568, 
      "heapUsed": 71120576 
     } 
    }, 
    "os": { 
     "loadavg": [0.0029296875, 0.0146484375, 0.04541015625], 
     "uptime": 397147 
    }, 
    "trace": [{ 
     "column": 13, 
     "file": "/path/to/my/file/node_modules/mysql/lib/protocol/Protocol.js", 
     "function": "Protocol.end", 
     "line": 109, 
     "method": "end", 
     "native": false 
    }, { 
     "column": 28, 
     "file": "/path/to/my/file/node_modules/mysql/lib/Connection.js", 
     "function": "", 
     "line": 102, 
     "method": null, 
     "native": false 
    }, { 
     "column": 20, 
     "file": "events.js", 
     "function": "emitNone", 
     "line": 72, 
     "method": null, 
     "native": false 
    }, { 
     "column": 7, 
     "file": "events.js", 
     "function": "Socket.emit", 
     "line": 166, 
     "method": "emit", 
     "native": false 
    }, { 
     "column": 12, 
     "file": "_stream_readable.js", 
     "function": "endReadableNT", 
     "line": 913, 
     "method": null, 
     "native": false 
    }, { 
     "column": 9, 
     "file": "node.js", 
     "function": "nextTickCallbackWith2Args", 
     "line": 442, 
     "method": null, 
     "native": false 
    }, { 
     "column": 17, 
     "file": "node.js", 
     "function": "process._tickDomainCallback", 
     "line": 397, 
     "method": "_tickDomainCallback", 
     "native": false 
    }], 
    "stack": ["Error: Connection lost: The server closed the connection.", " at Protocol.end (/path/to/my/file/node_modules/mysql/lib/protocol/Protocol.js:109:13)", " at Socket.<anonymous> (/path/to/my/file/node_modules/mysql/lib/Connection.js:102:28)", " at emitNone (events.js:72:20)", " at Socket.emit (events.js:166:7)", " at endReadableNT (_stream_readable.js:913:12)", " at nextTickCallbackWith2Args (node.js:442:9)", " at process._tickDomainCallback (node.js:397:17)"], 
    "level": "error", 
    "message": "uncaughtException: Connection lost: The server closed the connection.", 
    "timestamp": "2017-09-13T21:22:25.271Z" 
} 

無法找出爲什麼會發生這種情況？我也檢查了我的數據庫是否閒置，但我的數據庫是完美的，它不會閒置。那麼還有什麼會殺死我的節點進程？我已經做了幾個研究，哪些是殺死我的API我不知道。然後我開始通過api記錄請求，然後我發現了這個錯誤信息，並且只有在連續處理幾個小時後纔會出現。

Answer 1

您可以在堆棧跟蹤中看到您的MySQL數據庫連接正在被MySQL服務器自身關閉。

This issue給出了一點關於爲什麼服務器可能會斷開連接，以及如何增加MySQL服務器超時的背景。

Here is a similar question與一個答案，描述如何處理你的Node.js應用程序本身內的這個特定的錯誤事件。這對斷開連接時動態重新連接到MySQL服務器很有用。

如果您按照第二個鏈接中的示例安全地重新連接，則應該能夠阻止您的應用程序從這些數據庫超時。與簡單地延長超時長度相比，這是一個更爲嚴格的解決方案，尤其是因爲您不必完全依賴應用程序外部的行爲。