When connecting to MySQL from Node.js on AWS Lambda, “Quit inactivity timeout” appears.

When connecting to MySQL from Node.js on AWS Lambda, “Quit inactivity timeout” occasionally appears.In my case, this phenomenon has a 1/50 chance of getting an error.The module for MySQL connection that I used was installed as follows.

npm install mysql

The content of the error was as follows.

2020-12-31T09:53:06.051Z XXXX-XXXX-XXXX-XXXX-XXXX ERROR Uncaught Exception  {
    "errorType": "Error",
    "errorMessage": "Quit inactivity timeout",
    "code": "PROTOCOL_SEQUENCE_TIMEOUT",
    "fatal": true,
    "timeout": 30000,
    "stack": [
        "Error: Quit inactivity timeout",
        "    at Quit.<anonymous> (/var/task/node_modules/mysql/lib/protocol/Protocol.js:160:17)",
        "    at Quit.emit (events.js:314:20)",
        "    at Quit._onTimeout (/var/task/node_modules/mysql/lib/protocol/sequences/Sequence.js:124:8)",
        "    at Timer._onTimeout (/var/task/node_modules/mysql/lib/protocol/Timer.js:32:23)",
        "    at listOnTimeout (internal/timers.js:554:17)",
        "    at processTimers (internal/timers.js:497:7)"
    ]
}

I wrote “Quit inactivity timeout”, so I thought it was the end() function.So, I wrapped the end function processing with “Promise” function.By wrapping it with the “Promise” function, the error has disappeared so far.

Lambda Node.js MySQL接続でのUnknown application error occurred - Mjeld Technologies