jaimerson

 [alias]
 # lazy commit
 friday-night = !git commit -am 'Finish stuff' && git push origin `git symbolic-ref --short -q HEAD`
    
 # delete merged branches
 delete-merged = !git branch --merged | grep -v \* | xargs git branch -d

jaimerson

" Set vim-specific functions available, breaking compatibility with vi
set nocompatible
" Line Number
set number
" Syntax highlighting options
syntax on
set t_Co=256
" Search Options
set incsearch
set hlsearch

jaimerson

require 'rails_helper'

shared_examples 'a bikes report approach' do
  subject(:approach) { described_class.new }

  describe '#to_a' do
    let(:cheap_bike) { create(:bike, price: 3.14) }
    let(:expensive_bike) { create(:bike, price: 210) }

    let!(:cheap_rentals) do

jaimerson

class BikesReport::NaiveApproach
  def to_a
    rentals.group_by { |r| r.bike_id }.reduce([]) do |result, (id, rentals)|
      rental = rentals.first
      result << {
        name: rental.bike.name,
        model: rental.bike.model,
        times_rented: rentals.count,
        revenue: rental.bike.price * total_interval(rentals)
      }

jaimerson

Benchmark.bm { |x| x.report { BikesReport::NaiveApproach.new.to_a } }
#       user     system      total        real
#     9.670000   0.650000  10.320000 ( 10.540757)

jaimerson

class BikesReport::ActiveRecordSqlApproach
  def to_a
    Rental.joins(:bike)
      .select(query)
      .group('bikes.id')
      .order('times_rented DESC')
      .as_json(except: :id)
      .map { |r| r.symbolize_keys!.merge!(model: MODELS.fetch(r[:model])) }
  end

jaimerson

Benchmark.bm do |x|
   x.report(:naive) { BikesReport::NaiveApproach.new.to_a }
   x.report(:ar_and_sql) { BikesReport::ActiveRecordSqlApproach.new.to_a }
end
#        user     system      total        real
#   9.600000   0.790000  10.390000 ( 10.639153)
#   0.020000   0.000000   0.020000 (  0.137610)

jaimerson

class CreateBikesReportView < ActiveRecord::Migration
  def change
    reversible do |dir|
      dir.up do
        execute(
          <<-QUERY
            CREATE MATERIALIZED VIEW bikes_reports AS
              SELECT
              bikes.name, bikes.model,
              count(rentals.id) as times_rented,

jaimerson

class CreateBikesReports < ActiveRecord::Migration
  def change
    create_view :bikes_reports, materialized: true
  end
end

jaimerson

class BikesReport < ActiveRecord::Base
  def self.refresh
    Scenic
      .database
      .refresh_materialized_view(table_name, concurrently: false)
  end

  def readonly?
    true
  end