hellerbarde

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

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%' 

tototoshi

-- http://stackoverflow.com/questions/1124603/grouped-limit-in-postgresql-show-the-first-n-rows-for-each-group
-- http://www.postgresql.jp/document/9.2/html/tutorial-window.html

CREATE TABLE empsalary (
  depname varchar(10) not null
  , empno integer not null
  , salary integer not null
);

INSERT INTO empsalary (depname, empno, salary) VALUES ('develop', 11, 5200);

LeCoupa

#!/bin/bash
#####################################################
# Name: Bash CheatSheet for Mac OSX
# 
# A little overlook of the Bash basics
#
# Usage:
#
# Author: J. Le Coupanec
# Date: 2014/11/04

myusuf3

To remove a submodule you need to:

• Delete the relevant section from the .gitmodules file.
• Stage the .gitmodules changes git add .gitmodules
• Delete the relevant section from .git/config.
• Run git rm --cached path_to_submodule (no trailing slash).
• Run rm -rf .git/modules/path_to_submodule (no trailing slash).
• Commit git commit -m "Removed submodule "
• Delete the now untracked submodule files rm -rf path_to_submodule

akimboyko

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// #Using Actor

yiwenl

var saveJson = function(obj) {
	var str = JSON.stringify(obj);
	var data = encode( str );

	var blob = new Blob( [ data ], {
		type: 'application/octet-stream'
	});
	
	var url = URL.createObjectURL( blob );
	var link = document.createElement( 'a' );

skwasha

{
  "https://index.docker.io/v1/": {
    "auth": "<base64 encoded Docker username:password>",
    "email": "<Docker Account Email>"
  }
}

hbsdev

#!/bin/sh

# recursively removes all .pyc files and __pycache__ directories in the current
# directory

find . | grep -E "(__pycache__|\.pyc$)" | xargs rm -rf

needim

/*
  Based on:
  1. http://stephen.io/mediaqueries
  2. https://css-tricks.com/snippets/css/media-queries-for-standard-devices/
*/

/* iPhone X in portrait & landscape */
@media only screen 
and (min-device-width : 375px) 
and (max-device-width : 812px)