mabenson00

# Basic key operators to query the JSON objects :

# #> : Get the JSON object at that path (if you need to do something fancy)
# -> : Get the JSON object at that path (if you don't)
# ->> : Get the JSON object at that path as text
# {obj, n} : Get the nth item in that object

# https://www.postgresql.org/docs/9.4/functions-json.html#FUNCTIONS-JSONB-OP-TABLE
# Date 
# date before today

alassek

I've been doing some work lately with JSON documents in PostgreSQL using jsonb columns. You can query these documents using a GIN index in PG, but the syntax can be a little cumbersome

SELECT "events".* FROM "events" WHERE "events"."body" @> '{"shift":{"user_id":2}}'

You have to construct the right side of the query as a JSON string, which is a bit annoying. So I wondered if I could adapt Arel to do the tedious stuff for me.

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

mathiasbynens

#!/bin/bash

if [ "$1" = "-h" -o "$1" = "--help" -o -z "$1" ]; then cat <<EOF
appify v3.0.1 for Mac OS X - http://mths.be/appify
Creates the simplest possible Mac app from a shell script.

Appify takes a shell script as its first argument:

    `basename "$0"` my-script.sh

hagenburger

// Example:

JavaScript.load("/javascripts/something.js");


// With callback (that’s the good thing):

JavaScript.load("http://www.someawesomedomain.com/api.js", function() {
  API.use(); // or whatever api.js provides ...
});