PurpleBooth

Project Title

One Paragraph of project description goes here

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.

Prerequisites

pvdb

#
# This first version should work on Mac OS X and Linux, but it spawns a process
#
#     http://stackoverflow.com/questions/7220896/
#     https://github.com/rdp/os/blob/master/lib/os.rb#L127
#     http://www.ruby-doc.org/core-2.0/Process.html
#
# A better - but more complicated - way to achieve the same is documented here:
#
#     https://build.betterup.com/tracking-a-processs-memory-usage-in-ruby/

DGivney

section .text
global _start

_start:
  xor eax, eax              ; init eax 0
  xor ebx, ebx              ; init ebx 0
  xor esi, esi              ; init esi 0
  jmp _socket               ; jmp to _socket

_socket_call:

jstorimer

This is a proof-of-concept of a couple of concurrent data structures written in Ruby.

The implementations are heavily commented for those interested. There are benchmarks (with results) included below. The results are interesting, but, as always, take with a grain of salt.

Data structures

AtomicLinkedQueue is a lock-free queue, built on atomic CAS operations.

krisleech

class OrderController
  def new
    @order = Order.new
  end

  def create
    command = CreateOrder.new(current_user, params[:order])
    command.execute(:success => lambda { redirect_to orders_path },
                    :failure => lambda { |order| @order = order; render :action => :new })
  end

funny-falcon

Changes:

• this version includes backport of Greg Price's patch for speedup startup http://bugs.ruby-lang.org/issues/7158 .

  ruby-core prefers his way to do thing, so that I abandon cached-lp and sorted-lf patches of mine.

• this version integrates 'array as queue' patch, which improves performance when push/shift pattern is heavily used on Array.

  This patch is accepted into trunk for Ruby 2.0 and last possible bug is found by Yui Naruse. It is used in production* for a couple of months without issues even with this bug.

jnicklas

Capybara.add_selector :record do
  xpath { |record| XPath.css("#" + ActionController::RecordIdentifier.dom_id(record)) }
  match { |record| record.is_a?(ActiveRecord::Base) }
end

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%' 

terryjray

RAILS_ENV=production rake db:setup
# produces the error below.....hmmm.....it's a no-worky
psql:/yourprojectpath/yourproject/db/structure.sql:29: ERROR:  could not open extension control file "/usr/share/postgresql/9.1/extension/hstore.control": No such file or directory

# hstore postgresql extension needs to be installed, so....
sudo apt-get install postgresql-contrib

# now your extension should be available to enable so log in with psql
psql -d yourproject_production -U yourdbuser -W

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