janetlee

Installing Cassandra on Mac OS X

Install Homebrew

Homebrew is a great little package manager for OS X. If you haven't already, installing it is pretty easy:

ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"

janetlee

/**
  * Write a function that, given two objects, returns whether or not the two
  * are deeply equivalent--meaning the structure of the two objects is the
  * same, and so is the structure of each of their corresponding descendants.
  *
  * Examples:
  *
  * deepEquals({a:1, b: {c:3}},{a:1, b: {c:3}}); // true
  * deepEquals({a:1, b: {c:5}},{a:1, b: {c:6}}); // false
  *

janetlee

Latency Comparison Numbers
--------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

janetlee

require 'csv'
require 'json'
require "set"

json = JSON.parse(File.open(ARGV[0]).read)["results"]
# Pass 1: Collect headings
headings = SortedSet.new
json.each do |hash|
  headings.merge(hash.keys)
end