rkumar

#!/usr/bin/env ruby -w
## Using ruby's standard OptionParser to get subcommand's in command line arguments
## Note you cannot do: opt.rb help command
## other options are commander, main, GLI, trollop...

# run it as
# ruby opt.rb --help
# ruby opt.rb foo --help
# ruby opt.rb foo -q
# etc

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

apeckham

source :rubygems

gem 'thin'
gem 'sinatra-synchrony'
gem 'em-pg-client', require: %w'pg/em em-synchrony/pg'
gem 'rack-contrib'
gem 'rspec'
gem 'rack-test'

chanks

Turning PostgreSQL into a queue serving 10,000 jobs per second

RDBMS-based job queues have been criticized recently for being unable to handle heavy loads. And they deserve it, to some extent, because the queries used to safely lock a job have been pretty hairy. SELECT FOR UPDATE followed by an UPDATE works fine at first, but then you add more workers, and each is trying to SELECT FOR UPDATE the same row (and maybe throwing NOWAIT in there, then catching the errors and retrying), and things slow down.

On top of that, they have to actually update the row to mark it as locked, so the rest of your workers are sitting there waiting while one of them propagates its lock to disk (and the disks of however many servers you're replicating to). QueueClassic got some mileage out of the novel idea of randomly picking a row near the front of the queue to lock, but I can't still seem to get more than an an extra few hundred jobs per second out of it under heavy load.

So, many developers have started going straight t

jjwatt

(ns
    #^{:author "Jesse Wattenbarger"
       :doc "pulled out of a production program for gist."}
  coolquery.core
  (:gen-class)
  (:require [clojure.java.io :as io]
            [clojure.core.async :as a :refer
             [chan go go-loop close! <!! <! >! >!!]]
            [jdbc.core :as jdbc]            ;; good jdbc interop
            ))

terrybleger

package util.func

import co.paralleluniverse.fibers.*
import co.paralleluniverse.strands.SuspendableCallable
import co.paralleluniverse.strands.SuspendableRunnable
import io.vertx.core.Context
import io.vertx.core.Future
import io.vertx.core.Vertx
import java.util.concurrent.Executor

wfaler

sudo apt-get install bind9 bind9utils bind9-doc
wget https://dl.bintray.com/mitchellh/consul/0.5.2_linux_amd64.zip

/etc/bind/named.conf.options:
options {
        directory "/var/cache/bind";
        recursion yes;
        allow-query { localhost; };

        forwarders {

Faheetah

node {
    echo 'Results included as an inline comment exactly how they are returned as of Jenkins 2.121, with $BUILD_NUMBER = 1'
    echo 'No quotes, pipeline command in single quotes'
    sh 'echo $BUILD_NUMBER' // 1
    echo 'Double quotes are silently dropped'
    sh 'echo "$BUILD_NUMBER"' // 1
    echo 'Even escaped with a single backslash they are dropped'
    sh 'echo \"$BUILD_NUMBER\"' // 1
    echo 'Using two backslashes, the quotes are preserved'
    sh 'echo \\"$BUILD_NUMBER\\"' // "1"

grrywlsn

#!/bin/bash
# Set this script as the AWS user-data for a fresh CentOS AMI
# It will be run on startup, and logs to /var/log/cloud-init.log
rpm -iUvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
yum -y update
yum -y install epel-release
yum -y install ansible
yum -y install git
mkdir -p /home/centos/.ssh
cat <<EOF > /home/centos/.ssh/id_rsa

zloster

And the answer is:

688471 instructions

--@--:~$ uname -a
Linux 3.13.0-101-generic #148-Ubuntu SMP Thu Oct 20 22:09:17 UTC 2016 i686 i686 i686 GNU/Linux
--@--:~$ sudo perf stat echo test
test