all.rb

require_relative 'migration_helpers'
require_relative 'hypertable_helpers'

chunk.rb

module Timescale
  class Chunk < ActiveRecord::Base
    self.table_name = "timescaledb_information.chunks"

    def compress!
      execute("SELECT compress_chunk(#{chunk_relation})")
    end

    def decompress!
      execute("SELECT decompress_chunk(#{chunk_relation})")
    end

    def chunk_relation
      "('#{chunk_schema}.#{chunk_name}')::regclass"
    end

    def execute(sql)
      self.class.connection.execute(sql)
    end
  end
end

Gemfile

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.6.5'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 6.0.3', '>= 6.0.3.6'
# Use postgresql as the database for Active Record
gem 'pg', '>= 0.18', '< 2.0'
# Use Puma as the app server
gem 'puma', '~> 4.1'
# Use SCSS for stylesheets
gem 'sass-rails', '>= 6'
# Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '~> 5'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.7'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use Active Model has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Active Storage variant
# gem 'image_processing', '~> 1.2'

# Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', '>= 1.4.2', require: false

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
end

group :development do
  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '~> 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

group :test do
  # Adds support for Capybara system testing and selenium driver
  gem 'capybara', '>= 2.15'
  gem 'selenium-webdriver'
  # Easy installation and use of web drivers to run system tests with browsers
  gem 'webdrivers'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

gem "pry-rails", "~> 0.3.9"

gem "dotenv-rails"

gem "rspec-rails", "~> 5.0"

hypertable.rb

module Timescale
  class Hypertable < ActiveRecord::Base
    self.table_name = "timescaledb_information.hypertables"
  end
end

hypertable_helpers.rb

require_relative 'chunk'
require_relative 'hypertable'
module Timescale
  module HypertableHelpers
    extend ActiveSupport::Concern

    included do
      scope :chunks, -> () do
        Chunk.where(hypertable_name: self.table_name)
      end
      scope :hypertable, -> () do
        Hypertable.where(hypertable_name: self.table_name)
      end

      scope :last_month, -> { where('created_at > ?', 1.month.ago) }
      scope :last_week, -> { where('created_at > ?', 1.week.ago) }
      scope :last_hour, -> { where('created_at > ?', 1.hour.ago) }
      scope :yesterday, -> { where('DATE(created_at) = ?', 1.day.ago.to_date) }
      scope :today, -> { where('DATE(created_at) = ?', Date.today) }

      scope :counts_per, -> (time_dimension) {
        select("time_bucket('#{time_dimension}', created_at) as time, identifier, count(1) as total")
          .group(:time, :identifier).order(:time)
          .map {|result| [result.time, result.identifier, result.total]}
      }

      scope :detailed_size, -> do
        self.connection.execute("SELECT * from chunks_detailed_size('#{self.table_name}')")
          .map(&OpenStruct.method(:new))
      end

      scope :compression_stats, -> do
        self.connection.execute("SELECT * from hypertable_compression_stats('#{self.table_name}')")
          .map(&OpenStruct.method(:new))
      end
    end
  end
end

migration_helpers.rb

require 'active_record/connection_adapters/postgresql_adapter'

# Useful methods to run TimescaleDB in you Ruby app.
module Timescale
  # Migration helpers can help you to setup hypertables by default.
  module MigrationHelpers
    # create_table can receive `hypertable` argument
    # @example
    #  options = {
    #    time_column: 'created_at',
    #    chunk_time_interval: '1 min',
    #    compress_segmentby: 'identifier',
    #    compression_interval: '7 days'
    #  }
    #
    #  create_table(:events, id: false, hypertable: options) do |t|
    #    t.string :identifier, null: false
    #    t.jsonb :payload
    #    t.timestamps
    #  end
    def create_table(table_name, id: :primary_key, primary_key: nil, force: nil, **options)
      super
      setup_hypertable_options(table_name, **options[:hypertable]) if options.key?(:hypertable)
    end

    # Setup hypertable from options
    # @see create_table with the hypertable options.
    def setup_hypertable_options(table_name,
                                 time_column: 'created_at',
                                 chunk_time_interval: '1 week',
                                 compress_segmentby: nil,
                                 compression_interval: nil
                                )
      execute "SELECT create_hypertable('#{table_name}', '#{time_column}',
      chunk_time_interval => INTERVAL '#{chunk_time_interval}')"

      if compress_segmentby
        execute <<~SQL
        ALTER TABLE events SET (
          timescaledb.compress,
          timescaledb.compress_segmentby = '#{compress_segmentby}'
        )
        SQL
      end
      if compression_interval
        execute "SELECT add_compression_policy('#{table_name}', INTERVAL '#{compression_interval}')"
      end
    end
  end
end

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.include(Timescale::MigrationHelpers)

page_load.rb

class PageLoad < ApplicationRecord
  include Timescale::HypertableHelpers

  attribute :value
  scope :per_minute, -> { time_bucket('1 minute') }
  scope :per_hour, -> { time_bucket('1 hour') }
  scope :per_day, -> { time_bucket('1 day') }
  scope :per_week, -> { time_bucket('1 week') }
  scope :per_month, -> { time_bucket('1 month') }

  scope :average_response_time_per_minute, -> { time_bucket('1 minute', value: 'avg(performance)') }
  scope :average_response_time_per_hour,   -> { time_bucket('1 hour', value: 'avg(performance)') }
  scope :worst_response_time_last_minute,  -> { time_bucket('1 minute', value: 'max(performance)') }
  scope :worst_response_time_last_hour,    -> { time_bucket('1 hour', value: 'max(performance)') }
  scope :best_response_time_last_hour,     -> { time_bucket('1 hour', value: 'min(performance)') }

  scope :paths, -> { distinct.pluck(:path) }


  def self.statistics
    paths.each_with_object({}) do |path,resume |
      resume[path] = resume_for(path)
    end
  end

  def self.resume_for(path)
     filter = where(path: path)
     get = -> (scope_name) {  filter.send(scope_name).first.value}
     metrics.each_with_object({}) do |metric, resume|
       resume[metric] = get[metric]
     end
  end

  def self.metrics
    methods.grep /response_time/
  end
end

page_load_spec.rb

require 'rails_helper'
RSpec.describe PageLoad do
  describe "#create" do
    it "works as a hypertable" do
      expect do
        PageLoad.create user_agent: "test", path: "/", performance: 0.4
      end.to change { PageLoad.chunks.size }.from(0).to(1)
    end
  end

end

rails_helper.rb

# This file is copied to spec/ when you run 'rails generate rspec:install'
require 'spec_helper'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../config/environment', __dir__)
# Prevent database truncation if the environment is production
abort("The Rails environment is running in production mode!") if Rails.env.production?
require 'rspec/rails'
# Add additional requires below this line. Rails is not loaded until this point!

# Requires supporting ruby files with custom matchers and macros, etc, in
# spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
# run as spec files by default. This means that files in spec/support that end
# in _spec.rb will both be required and run as specs, causing the specs to be
# run twice. It is recommended that you do not name files matching this glob to
# end with _spec.rb. You can configure this pattern with the --pattern
# option on the command line or in ~/.rspec, .rspec or `.rspec-local`.
#
# The following line is provided for convenience purposes. It has the downside
# of increasing the boot-up time by auto-requiring all files in the support
# directory. Alternatively, in the individual `*_spec.rb` files, manually
# require only the support files necessary.
#
# Dir[Rails.root.join('spec', 'support', '**', '*.rb')].sort.each { |f| require f }

# Checks for pending migrations and applies them before tests are run.
# If you are not using ActiveRecord, you can remove these lines.
begin
  ActiveRecord::Migration.maintain_test_schema!
rescue ActiveRecord::PendingMigrationError => e
  puts e.to_s.strip
  exit 1
end
RSpec.configure do |config|
  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
  config.fixture_path = "#{::Rails.root}/spec/fixtures"

  # If you're not using ActiveRecord, or you'd prefer not to run each of your
  # examples within a transaction, remove the following line or assign false
  # instead of true.
  config.use_transactional_fixtures = true

  # You can uncomment this line to turn off ActiveRecord support entirely.
  # config.use_active_record = false

  # RSpec Rails can automatically mix in different behaviours to your tests
  # based on their file location, for example enabling you to call `get` and
  # `post` in specs under `spec/controllers`.
  #
  # You can disable this behaviour by removing the line below, and instead
  # explicitly tag your specs with their type, e.g.:
  #
  #     RSpec.describe UsersController, type: :controller do
  #       # ...
  #     end
  #
  # The different available types are documented in the features, such as in
  # https://relishapp.com/rspec/rspec-rails/docs
  config.infer_spec_type_from_file_location!

  # Filter lines from Rails gems in backtraces.
  config.filter_rails_from_backtrace!
  # arbitrary gems may also be filtered via:
  # config.filter_gems_from_backtrace("gem name")
  #
  # Timescale Befor Start Suite, set Hypertables
  config.before(:suite) do

    hypertable_models = ApplicationRecord
      .descendants
      .select{|clazz| clazz.ancestors.include?( Timescale::HypertableHelpers)}
    hypertable_models.each do |clazz|
      if clazz.hypertable.exists?
        ApplicationRecord.logger.info "skip recreating hypertable for '#{clazz.table_name}'."
        next
      end
      ApplicationRecord.connection.execute <<~SQL
        SELECT create_hypertable('#{clazz.table_name}', 'created_at')
      SQL

    end

  end
end

timescale.rb

require 'timescale/all'