Using CreateConnections Only Slows Down the Server

[bailejl]

I am trying to restrict model access to one or more connections with the hope of limiting access based on user permissions. I have the code working, but when I remove the mongoose.connect, it slows everything down. The times are in the 20-50 seconds on my local desktop in development mode. However, If I add mongoose.connect, everything is under a second. Any help is appreciated.

db.js

"use strict";

var mongoose = require('mongoose');
var logger = require('winston');
var nconf = require('nconf');


var dbUrl = nconf.get("database:acl:url");

mongoose.connect(dbUrl, function (err) {
    if (err) {
        logger.error('Error connecting to DB from mongoose', err);
        throw err;
    }
    logger.info('Mongoose is connected to ' + dbUrl);
});

module.exports = mongoose;

var hostReadOnly = nconf.get("database:read-only:host");
var databaseReadOnly = nconf.get("database:read-only:database");
var portReadOnly = nconf.get("database:read-only:port");
var optionsReadOnly = nconf.get("database:read-only:options");

var readOnlyConnection = mongoose.createConnection(hostReadOnly, databaseReadOnly, portReadOnly, optionsReadOnly);
readOnlyConnection.on('error', function (err) {
    if (err) {
        logger.error('Error with Read-Only DB from mongoose', err);
        throw err;
    }
});
readOnlyConnection.on('connected', function(err){
    if (err) {
        logger.error('Error connecting with Read-Only DB from mongoose', err);
        throw err;
    }

    logger.info('Mongoose is connected to Read-Only DB via ' + hostReadOnly + ':' + portReadOnly +
        '/' + databaseReadOnly);
});


var hostReadWrite = nconf.get("database:read-write:host");
var databaseReadWrite = nconf.get("database:read-write:database");
var portReadWrite = nconf.get("database:read-write:port");
var optionsReadWrite = nconf.get("database:read-write:options");
var readWriteConnection = mongoose.createConnection(hostReadWrite, databaseReadWrite, portReadWrite, optionsReadWrite);
readWriteConnection.on('error', function (err) {
    if (err) {
        logger.error('Error with Read-Write DB from mongoose', err);
        throw err;
    }
});
readWriteConnection.on('connected', function(err){
    if (err) {
        logger.error('Error connecting with Read-Write DB from mongoose', err);
        throw err;
    }
    logger.info('Mongoose is connected to Read-Write DB via ' + hostReadWrite + ':' + portReadWrite + '/' +
        databaseReadWrite );
});

var hostAdmin = nconf.get("database:admin:host");
var databaseAdmin = nconf.get("database:admin:database");
var portAdmin = nconf.get("database:admin:port");
var optionsAdmin = nconf.get("database:admin:options");
var adminConnection = mongoose.createConnection(hostAdmin, databaseAdmin, portAdmin, optionsAdmin);
adminConnection.on('error', function (err) {
    if (err) {
        logger.error('Error with Admin DB from mongoose', err);
        throw err;
    }
});
adminConnection.on('connected', function(err){
    if (err) {
        logger.error('Error connecting with Admin DB from mongoose', err);
        throw err;
    }
    logger.info('Mongoose is connected to Admin DB via ' + hostAdmin + ':' + portAdmin + '/' +
        databaseAdmin );
});

module.exports.readOnlyConnection = readOnlyConnection;
module.exports.readWriteConnection = readWriteConnection;
module.exports.adminConnection = adminConnection;

permission.js

var mongoose = require('mongoose');
var createInfo = require('./plugins/creationInfo');
var modifiedOn = require('./plugins/modifiedOn');
var versionInfo = require('./plugins/versionInfo');
var db = require('../db');

var schema = new mongoose.Schema({
        name: { type: String, required: true },
        description: { type: String, required: false }
    }
);

schema.plugin(modifiedOn);
schema.plugin(createInfo);
schema.plugin(versionInfo);

db.readOnlyConnection.model('Permission', schema);
db.readWriteConnection.model('Permission', schema);
db.adminConnection.model('Permission', schema);

module.exports.schema = schema;

I access the model with the following code.

var db = require('../db'),
    User = db.readOnlyConnection.model('User');

[vkarpov15]

What times are you measuring?

[bailejl]

@vkarpov15 I appreciate you tagging it with help and question, but I found the issue. Express in our code is using the default Mongoose connection to store session info, which was causing the problem. After creating its own connection, the times went back to normal. I hope people can benefit from this problem.

[vkarpov15]

I'd recommend you use connect-mongodb-session for storage instead of connect-mongo: https://github.com/mongodb-js/connect-mongodb-session . I've seen far too many problems with the connection pool reuse with connect-mongo.