According to [connPoolStats][1]
this command .`connPoolStats`. returns information regarding the open outgoing connections from the current database instance to other members of the sharded cluster or replica set.
db.runCommand( { "connPoolStats" : 1 } )
The value of the argument (i.e. 1 ) does not affect the output of your the command.
According to [connection pool options][2]
The maximum number of connections in the connection pool.
**The default value is 100**.
According to this it can be done [deep-dive-into-connection-pooling][3]
var express = require('express');
var mongodb = require('mongodb');
var app = express();
var MONGODB_URI = 'mongo-uri';
app.get('/', function(req, res) {
// BAD! Creates a new connection pool for every request
mongodb.MongoClient.connect(MONGODB_URI, function(err, db) {
if(err) throw err;
var coll = db.collection('test');
coll.find({}, function(err, docs) {
docs.each(function(err, doc) {
if(doc) {
res.write(JSON.stringify(doc) + "\n");
}
else {
res.end();
}
});
});
});
});
// App may initialize before DB connection is ready
app.listen(3000);
console.log('Listening on port 3000');
[1]: https://docs.mongodb.com/manual/reference/command/connPoolStats/
[2]: https://docs.mongodb.com/manual/reference/connection-string/#connection-pool-options
[3]: https://blog.mlab.com/2013/11/deep-dive-into-connection-pooling/
If you opt for using mongoose in your application edit your app.js file with the following snippet
**app.js**
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/Your_Data_Base_Name', {useNewUrlParser:true})
.then((res) => {
console.log(' ########### Connected to mongDB ###########');
})
.catch((err) => {
console.log('Error in connecting to mongoDb' + err);
});`
**Next Step:**
Define Models for your application require them and perform CRUD operation directly for example
**blogSchema.js**
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const blogSchema = new Schema({
_id : mongoose.Schema.Types.ObjectId,
title : {
type : 'String',
unique : true,
required : true
},
description : String,
comments : [{type : mongoose.Schema.Types.ObjectId, ref: 'Comment'}]
});
module.exports = mongoose.model('Blog', blogSchema);
**Usage**
**createBlog.js**
const Blog = require('../models/blogSchema');
exports.createBlog = (req, res, next) => {
const blog = new Blog({
_id : new mongoose.Types.ObjectId,
title : req.body.title,
description : req.body.description,
});
blog.save((err, blog) => {
if(err){
console.log('Server Error save fun failed');
res.status(500).json({
msg : "Error occured on server side",
err : err
})
}else{
//do something....
}
U don't need to connect to mogoDB always ....
