pesterhazy

So you want to write a sync system for a web app with offline and realtime support? Good luck. You might find the following resources useful.

Overview articles

• Database in a browser, a spec (Stepan Parunashvili)

  What problem are we trying to solve with a sync system?

• The web of tomorrow (Nikita Prokopov)

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

inexorabletash

Indexed DB - N-Dimensional Selection

The problem

We have an index with keys of the form:

[ dim1, dim2, dim3, ... ]

e.g. created with:

seanlinehan

appalled
ashamed
asshole
complicit
deplorable
deplore
disgraceful
disgusted
fuck
fucking

JuggoPop

# To Setup:
# 1) Save the .git-completion.bash file found here:
#    https://github.com/git/git/blob/master/contrib/completion/git-completion.bash
# 2) Add the following lines to your .bash_profile, be sure to reload (for example: source ~/.bash_profile) for the changes to take effect:

# Git branch bash completion
if [ -f ~/.git-completion.bash ]; then
  . ~/.git-completion.bash
  
  # Add git completion to aliases

adamwiggins

Make it real

Ideas are cheap. Make a prototype, sketch a CLI session, draw a wireframe. Discuss around concrete examples, not hand-waving abstractions. Don't say you did something, provide a URL that proves it.

Ship it

Nothing is real until it's being used by a real user. This doesn't mean you make a prototype in the morning and blog about it in the evening. It means you find one person you believe your product will help and try to get them to use it.

Do it with style

piscisaureus

Locate the section for your github remote in the .git/config file. It looks like this:

[remote "origin"]
	fetch = +refs/heads/*:refs/remotes/origin/*
	url = git@github.com:joyent/node.git

Now add the line fetch = +refs/pull/*/head:refs/remotes/origin/pr/* to this section. Obviously, change the github url to match your project's URL. It ends up looking like this:

semperos

;; Big thanks to Christophe Grand - https://groups.google.com/d/msg/clojure/L1GiqSyQVVg/m-WJogaqU8sJ
(defn scaffold [iface]
  (doseq [[iface methods] (->> iface .getMethods 
                            (map #(vector (.getName (.getDeclaringClass %)) 
                                    (symbol (.getName %))
                                    (count (.getParameterTypes %))))
                            (group-by first))]
    (println (str "  " iface))
    (doseq [[_ name argcount] methods]
      (println 

scy

Opening and closing an SSH tunnel in a shell script the smart way

I recently had the following problem:

• From an unattended shell script (called by Jenkins), run a command-line tool that accesses the MySQL database on another host.
• That tool doesn't know that the database is on another host, plus the MySQL port on that host is firewalled and not accessible from other machines.

We didn't want to open the MySQL port to the network, but it's possible to SSH from the Jenkins machine to the MySQL machine. So, basically you would do something like

ssh -L 3306:localhost:3306 remotehost

nickloewen

This is a plain-text version of Bret Victor’s reading list. It was requested by hf on Hacker News.

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Highly recommended things!

This is my five-star list. These are my favorite things in all the world.

A few of these works have had an extraordinary effect on my life or way of thinking. They get a sixth star. ★