RobinDaugherty

This is an analysis of the existing Widget PinCache performance trying different storage objects. The baseline is the implementation that uses LruRedux::TTL::Cache (which is not the threadsafe version).

I tried replacing this with a native Ruby Hash, and in the case of the negative cache, I also tried instead replacing it with a native Set object.

I also tried the same using a binary tree implemented within the Ruby interpreter.

Profiling was done with JRuby 1.7.22 in Ruby 2.0 mode. The process was restarted before each run.

1/5 Cache Hit Rate, 20% Negative Response Rate

RobinDaugherty

# Start with a broken commit, this will walk back to the first working commit.
until bundle; do
  cd ../rubygems
  git reset --hard HEAD^
  ruby setup.rb --no-document
  cd ../jruby-test
done

RobinDaugherty

$ dig rubygems.org

; <<>> DiG 9.9.5-3ubuntu0.7-Ubuntu <<>> rubygems.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10778
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096

RobinDaugherty

$ wget https://rubygems.org/gems/rake-10.5.0.gem
--2016-02-11 21:30:29--  https://rubygems.org/gems/rake-10.5.0.gem
Resolving rubygems.org (rubygems.org)... 54.186.104.15
Connecting to rubygems.org (rubygems.org)|54.186.104.15|:443... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https://rubygems.global.ssl.fastly.net/gems/rake-10.5.0.gem [following]
--2016-02-11 21:30:30--  https://rubygems.global.ssl.fastly.net/gems/rake-10.5.0.gem
Resolving rubygems.global.ssl.fastly.net (rubygems.global.ssl.fastly.net)... 185.31.19.249, 185.31.18.249
Connecting to rubygems.global.ssl.fastly.net (rubygems.global.ssl.fastly.net)|185.31.19.249|:443... connected.
HTTP request sent, awaiting response... 200 OK

RobinDaugherty

1. check the cache and return the value if found
2. with mutex locked 1. if the ID is currently in flight, get its condition variable 2. if ID is not in flight, check the cache again for the item
   1. if it was in the cache, return the item
   2. if not in the cache
   3. if there's room for another in-flight request 1. add a condition variable to the list of in-flight requests
3. if the ID was already in flight, wait on the condition variable we got for it
4. when the condition variable signals, return the item from the cache

RobinDaugherty

module Concerns
  module HasOneAutoCreated
    extend ActiveSupport::Concern

    module ClassMethods
      def has_one_auto_created(association_name, options = {})
        has_one association_name, options

        alias_method "existing_#{association_name}", association_name

RobinDaugherty

class CreateGadgets < ActiveRecord::Migration
  def change
    create_table "gadgets" do |t|
      t.string "info"
    end
  end
end

RobinDaugherty

class CreateGadgets < ActiveRecord::Migration
  def change
    create_table "gadgets" do |t|
      t.json "info"
    end
  end
end

RobinDaugherty

brew tap josegonzalez/homebrew-php
brew tap homebrew/dupes
brew install --enable-cgi php56

RobinDaugherty

require 'github_api'

github = Github.new(
  oauth_token: 'fill-me-in',
  auto_pagination: true,
)

# Returns ALL OPEN ISSUES. Learned the hard way that the `label` parameter does nothing here.
open_issues = github.issues.list(user: 'lemurheavy', repo: 'coveralls', state: 'open')