node.js
DESCRIPTION
TRANSCRIPT
Introduction
"Node's goal is to provide an easy way to build scalable network programs."
Ryan Dahl
● Server-side Javascript
● Built on Google’s V8
● CommonJS module system
● Evented, non-blocking I/O. Similar to EventMachine or Twisted.
I/O needs to be done differently.
I/O Costs
●L1: 3 cycles
●L2: 14 cycles
●RAM: 250 cycles
●DISK: 41,000,000 cycles
●NETWORK: 240,000,000 cycles
http://nodejs.org/jsconf.pdf
Traditional way
var db = require('db');
row = db.query(' SELECT id, name FROM aaa');
row2 = db.query('SELECT id, name WHERE id = '+row.id );
// do your stuff hereconsole.log( row2.name );
I/O Costs
●L1: 3 cycles
●L2: 14 cycles
●RAM: 250 cycles
●DISK: 41,000,000 cycles
●NETWORK: 240,000,000 cycles
http://nodejs.org/jsconf.pdf
Node's first attempt
var db = require('db');
db.query(' SELECT id, name FROM table', function(row){ db.query('SELECT .... WHERE id = '+row.id, function(row2){
// do your stuff here console.log( row2.name ); });});
Better wayvar db = require('db');
frunction get(cb){ db.query('SELECT id, name FROM table', row1);}
function row1(row, cb){ db.query('SELECT .... WHERE id = '+ row.id, function(row){ cb( row ); });}
get(function(row){ console.log( row.name );});
speed
speed
var http = require(’http’);var b = new Buffer(1024*1024);
http.createServer(function(req, res){ res.writeHead(200); res.end(b);}).listen(8000);
by Ryan Dahl
speed
100 concurrent clients1 megabyte response
req/sec
node ~800nginx ~700
thin 85mongrel 4
(bigger is better)by Ryan Dahl
Questions?