jboner

Latency Comparison Numbers (~2012)
----------------------------------
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

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

samselikoff

This post is also on my blog, since Gist doesn't support @ notifications.

---

Components are taking center stage in Ember 2.0. Here are some things you can do today to make the transition as smooth as possible:

• Use Ember CLI
• In general, replace views + controllers with components
• Only use controllers at the top-level for receiving data from the route, and use Ember.Controller instead of Ember.ArrayController or Ember.ObjectController
• Fetch data in your route, and set it as normal properties on your top-level controller. Export an Ember.Controller, otherwise a proxy will be generated. You can use Ember.RSVP.hash to simulate setting normal props on your controller.

reborg

Rich Already Answered That!

A list of commonly asked questions, design decisions, reasons why Clojure is the way it is as they were answered directly by Rich (even when from many years ago, those answers are pretty much valid today!). Feel free to point friends and colleagues here next time they ask (again). Answers are pasted verbatim (I've made small adjustments for readibility, but never changed a sentence) from mailing lists, articles, chats.

How to use:

• The link in the table of content jumps at the copy of the answer on this page.
• The link on the answer itself points back at the original post.

Table of Content

merlinmann

Merlin's Wisdom Project

Or: “Everybody likes being given a glass of water.”

By Merlin Mann.

It's only advice for you because it had to be advice for me.

jamtur01

These are the Kickstarter Engineering and Data role definitions for both teams.

Technical	Data	People
Junior Software Engineer
Software Engineer	Data Analyst
Senior Software Engineer	Data Scientist	Engineering Manager
Staff Engineer	VP of Data	Engineering Director
Principal Engineer		CTO

jallspaw

Adrian -

I appreciate that you spent time in writing this post. I know I've been up until 2am writing similarly long ones as well. I will take responsibility for having what is likely an irrational response (I blame Twitter for that) to the term "NoOps", but I invite you to investigate why that might be. I'm certainly not the only one who feels this way, apparently, and thus far have decided this issue is easily the largest distraction in my field I've encountered in recent years. I have had the option to simply ignore my opposition to the term, and just let the chips fall where they may with how popular the term "NoOps" may or may not get. I have obviously not taken that option in the past, but I plan to in the future.

You're not an analyst saying "NoOps". Analysts are easy (for me) to ignore, because they're not practitioners. We have expectations of engineering maturity from practitioners in this field of web engineering, especially those we consider leaders. I don't have any expectations from analysts,

acolyer

Internet Scale Services Checklist

A checklist for designing and developing internet scale services, inspired by James Hamilton's 2007 paper "On Desgining and Deploying Internet-Scale Services."

• http://mvdirona.com/jrh/talksandpapers/jamesrh_lisa.pdf

Basic tenets

• Does the design expect failures to happen regularly and handle them gracefully?
• Have we kept things as simple as possible?

headius

class Proc
  def <<(other)
    case other
    when Proc
      Proc.new do |*args|
        call(other.call(*args))
      end
    else
      call(other)
    end