all4miller

drop table if exists datadz;
    
create table if not exists datadz (
    datestmp date,
    user_id integer,
    stat double precision
);

insert into datadz
select date(datestmp),

all4miller

drop table if exists datatz;
    
create table if not exists datatz (
    timestmp timestamp,
    user_id integer,
    stat double precision
);

insert into datatz
select timestmp,

all4miller

# BAD each iteration loads invoice model

class Company < ApplicationRecord
  has_many :invoices
end

class Invoice < ApplicationRecord
  belongs_to :company
end

all4miller

Given the below PostgreSQL compatible SQL

with calendar
as (
	select t.day::date,
		trunc(random() * 3 + 1) max_version_daily,
		trunc(random() * 3 + 1) max_version_hourly
	from generate_series(timestamp '2010-01-01', timestamp '2022-01-31', interval '1 day') as t(day)
	),

all4miller

  "browserify": {
    "transform": [
      [
        "coffeeify",
        {
          "extension": ".js.coffee"
        }
      ],
      [
        "babelify",

all4miller

drop table if exists shipments;
create table shipments (
  id serial primary key not null,
  sender_address_id integer not null,
  sender_contact_id integer not null,
  receiver_address_id integer not null,
  receiver_contact_id integer not null,
  created_at timestamp not null default current_timestamp,
  units integer not null,
  zar_value numeric not null

all4miller

create view dbo.FuckingSlow
as
  select 'derivatives'                    as section,
         Rtrim(Accounts.indicator)
         + Rtrim(Departments.indicator)
         + Rtrim(Products.indicator)    as 'Account',
         Rtrim(Accounts.indicator)
         + Rtrim(Departments.indicator)
         + Rtrim(Products.indicator) + '0000'
         + Rtrim(Derivatives.indicator) as 'FullAccount',

all4miller

# frozen_string_literal: true

require 'benchmark'
require 'benchmark/ips'
require 'benchmark/memory'
require 'csv'

N_NUMBER_OF = 100_000

ary = Array.new(N_NUMBER_OF) { ['one', 'two', 'three', 'four', 'five', 'six'] }

all4miller

  def average_time_in_hours_to_2_or_more_views
    Businesss.where.not(date_achieved_2_views: nil).pluck('sum(abs(extract(epoch from created_at - date_achieved_2_links)/3600)) / count(*)').first
  end

all4miller

  def average_time_in_hours_to_2_or_more_view
    businesses = Businesss.where.not(date_achieved_2_views: nil)
    hours_sum = 0
    businesses.map do |business|
      hours_sum += TimeDifference.between(business.created_at, business.date_achieved_2_views).in_hours
    end
    return nil if hours_sum.blank? || businesses.count.blank?
    hours_sum / businesses.count
  end