Michal Bernhard michalbcz

NDJSON is a convenient format for storing or streaming structured data that may be processed one record at a time.

Each line is a valid JSON value
Line separator is ‘\n’

1. Convert JSON to NDJSON?

cat test.json | jq -c '.[]' > testNDJSON.json

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

	"use strict";

	var API_KEY = '__API_KEY__';
	var PHOTOSET_IDS = ['__ID1__', '__ID2__', '__ID3__'];

	var cartagenaApp = angular.module('cartagenaApp');

	cartagenaApp.directive('flickrBackground', function(Flickr, $http) {
	var _flickrBackground = function($scope, $element) {
	var nextPhoto;

	private void test(List<ExchangeRate> exchangeRates) {
	Map<String, ExchangeRate> rateType11Map = new HashMap<String, ExchangeRate>();
	Map<String, ExchangeRate> rateType12Map = new HashMap<String, ExchangeRate>();

	Collections.sort(exchangeRates, new Comparator<ExchangeRate>() {
	@Override
	public int compare(ExchangeRate e1, ExchangeRate e2) {
	return ComparisonChain.start()
	.compare(e1.getRateCurrency(), e2.getRateCurrency())
	.compare(e1.getRateType(), e2.getRateType())

	def generateMD5(String s) {
	MessageDigest digest = MessageDigest.getInstance("MD5")
	digest.update(s.bytes);
	new BigInteger(1, digest.digest()).toString(16).padLeft(32, '0')
	}

	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
	Send 1K bytes over 1 Gbps network 10,000 ns 0.01 ms
	Read 4K randomly from SSD* 150,000 ns 0.15 ms