Network Performance Issue with Mongoose Writes

Question

I have the following code to modify a user account in my application:

"use strict";

var mongoose = require("mongoose");

mongoose.set("debug", true);

mongoose.connect(process.env.MONGO_URL, {
    auth: {
        user: process.env.MONGO_USER,
        password: process.env.MONGO_PASSWD,
    },
    useNewUrlParser: true,
    useUnifiedTopology: false,
});

var db = mongoose.connection;

var schema = mongoose.Schema;

var user_schema = new schema(
    {
        id: { type: String, required: true, unique: true },
        username: { type: String, required: true },
        name: String,
        email: String,
        phone: String,
        created: Date,
        modified: Date,
    },
    { strict: false }
);

var query = user.where({ id: user_id }),
    user_id = "93", // temporarily hard-coded as an example
    user_modified = null,
    result = -1; // failure

db.on("error", console.error.bind(console, "connection error:"));
db.once("open", function () {
    async () => {
        await query.findOne(function (err, user) {
            if (err) {
                console.log(err);
            }
            if (user) {
                user.modified = Date();
                user_modified = user;
            }
        });

        if (user_modified) {
            try {
                let save_user = await user_modified.save();
                if (save_user) {
                    result = 1; // success
                }
            } catch (err) {
                console.log(err);
            }
        }

        console.log(result);
    };
});

This assumes that the user account 93 is already created in the MongoDB database:

{
  "_id": ObjectId("5e7d3c3d0a6467c8b554abf4"),
  "id": "93",
  "username": "foo",
  "name": "bar",
  "email": 'baz@mail.com',
  "phone": '1234567890',
  "created": "2000-01-01 01:10:01.553",
  "modified": "2000-01-01 01:10:01.553"
}

I have this code running on an ec2 instance in us-east-2, eu-west-1, and ap-southeast-1. I am also based in the Eastern United States.

Here is my MongoDB connection string:

MONGO_URL: "mongodb://us-east-2.foo.com:27017,eu-west-1.foo.com:27017,ap-southeast-1.foo.com:27017/bar?authSource=admin&replicaSet=bz0&readPreference=secondary"

When I hit the us-east-2 instance, it always returns 1 (success) for me. But if I try to hit the eu-west-1 or ap-southeast-1 instance(s), it inconsistently returns -1 (failure).

Note: I have also experienced failures by using a single MongoDB instance instead of a ReplicaSet. It fails whenever I try to connect across regions.

Reference(s):

This may be obvious, but have you made sure you can actually connect to your MongoDB from your EU instance? — codemonkey, Feb 02 '21 at 21:01

score 0 · Accepted Answer · answered Feb 08 '21 at 17:59

useUnifiedTopology - False by default. Set to true to opt in to using the MongoDB driver's new connection management engine. You should set this option to true, except for the unlikely case that it prevents you from maintaining a stable connection.

"use strict";

var mongoose = require("mongoose");

mongoose.set("debug", true);

mongoose.connect(process.env.MONGO_URL, {
    auth: {
        user: process.env.MONGO_USER,
        password: process.env.MONGO_PASSWD,
    },
    useNewUrlParser: true,
    useUnifiedTopology: true,
});

var db = mongoose.connection;

var schema = mongoose.Schema;

var user_schema = new schema(
    {
        id: { type: String, required: true, unique: true },
        username: { type: String, required: true },
        name: String,
        email: String,
        phone: String,
        created: Date,
        modified: Date,
    },
    { strict: false }
);

var query = user.where({ id: user_id }),
    user_id = "93", // temporarily hard-coded as an example
    user_modified = null,
    result = -1; // failure

db.on("error", console.error.bind(console, "connection error:"));
db.once("open", async function () {
    try {
        var user = await query.findOne();

        if (user) {
            user.modified = Date();
            user_modified = user;
        }

        if (user_modified) {
            try {
                let save_user = await user_modified.save();
                if (save_user) {
                    result = 1; // success
                }
            } catch (err) {
                console.log(err);
            }
        }
        console.log(result);
    } catch (err) {
        if (err) {
            console.log(err);
        }
    }
});

Reference(s):

Network Performance Issue with Mongoose Writes

1 Answers1