Node.js MongoError:到群集的连接4已关闭

我使用Mongoose驱动程序在NodeJS中有一个函数，如下所示：

伪代码：

在步骤3，我得到以下错误：

MongoError: connection 4 to cluster closed
at Function.MongoError.create (/home/some-user/my-repo/node_modules/mongodb-core/lib/error.js:29:11)
at TLSSocket.<anonymous> (/home/some-user/my-repo/node_modules/mongodb-core/lib/connection/connection.js:202:22)
at Object.onceWrapper (events.js:293:19)
at emitOne (events.js:101:20)
at TLSSocket.emit (events.js:191:7)
at _handle.close (net.js:513:12)
at Socket.done (_tls_wrap.js:332:7)
at Object.onceWrapper (events.js:293:19)
at emitOne (events.js:101:20)
at Socket.emit (events.js:191:7)
at TCP._handle.close [as _onclose] (net.js:513:12)

---

我不明白为什么在第3步会出现这个错误。有人能帮我解决这个问题吗？

经过几个小时的调试，终于解决了这个问题。从第2步开始，我的第3步mongoose查询中的文档太多，大约有数百万个。mongoose的错误没有给出连接关闭的原因。像文档太多或查询太大这样的消息会大大节省时间

MongoError: connection 4 to cluster closed
at Function.MongoError.create (/home/some-user/my-repo/node_modules/mongodb-core/lib/error.js:29:11)
at TLSSocket.<anonymous> (/home/some-user/my-repo/node_modules/mongodb-core/lib/connection/connection.js:202:22)
at Object.onceWrapper (events.js:293:19)
at emitOne (events.js:101:20)
at TLSSocket.emit (events.js:191:7)
at _handle.close (net.js:513:12)
at Socket.done (_tls_wrap.js:332:7)
at Object.onceWrapper (events.js:293:19)
at emitOne (events.js:101:20)
at Socket.emit (events.js:191:7)
at TCP._handle.close [as _onclose] (net.js:513:12)

mongoose.connect(connStr, {
    server: {
        socketOptions: {
            keepAlive: 300000,
            connectTimeoutMS: 300000,
            socketTimeoutMS: 300000,
            auto_reconnect: true
        }
    }
});