hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

justinko

Dear Rubyists,

I just lost a contract because of my code in a Rails project.

The specific code in question is related to a "posting a comment" feature. Here are the details:

In this project, "posting a comment" does not simply entail inserting a row into the database. It involves a procedure to yes, insert a row, but also detect its language, check for spam, send emails, and "share" it to Twitter and Facebook. I believe this algorithm should be encapsulated. I do not believe it belongs in a controller or a model. I do not believe Active Record callbacks should be used.

The "senior developer", whom is the stake holder's right hand man, said this:

Fitzsimmons

This guide will get you started using Spark on Heroku/Cedar. Spark is basically a clone of Sinatra for Java. 'Nuff said.

Create your app

Create a single Java main class in src/main/java/HelloWorld.java:

import static spark.Spark.*;
import spark.*;

bschaeffer

ids = [1,2,3]

def targs(*ids)
  puts ids.length
  puts ids.flatten.length
end

targs ids
#=> 1
#=> 3

jesperfj

This guide will get you started using Spark on Heroku/Cedar. Spark is basically a clone of Sinatra for Java. 'Nuff said.

Create your app

Create a single Java main class in src/main/java/HelloWorld.java:

:::java
import static spark.Spark.*;
import spark.*;

pietern

require 'rubygems'
require 'sinatra'
require 'redis'

# To use, simply start your Redis server and boot this
# example app with:
#   ruby example_note_keeping_app.rb
#
# Point your browser to http://localhost:4567 and enjoy!
#