really faster stats by precomputing some of them

app/controllers/stats_controller.rb

@@ -4,7 +4,7 @@ class StatsController < ApplicationController
   MEAN_NUMBER_OF_CHAMPS_IN_A_FORM = 24.0
 
   def index
-    @dossiers_states = dossiers_states
+    stat = Stat.first
 
     procedures = Procedure.publiees_ou_closes
     dossiers = Dossier.state_not_brouillon
@@ -12,22 +12,27 @@ class StatsController < ApplicationController
     @procedures_numbers = procedures_numbers(procedures)
 
     @dossiers_numbers = dossiers_numbers(
-      @dossiers_states['not_brouillon'],
+      stat.dossiers_not_brouillon,
-      @dossiers_states['last_30_days_count'],
+      stat.dossiers_depose_avant_30_jours,
-      @dossiers_states['previous_count']
+      stat.dossiers_deposes_entre_60_et_30_jours
     )
 
     @satisfaction_usagers = satisfaction_usagers
 
     @contact_percentage = contact_percentage
 
-    @dossiers_states_for_pie = @dossiers_states.slice("Brouillon", "En construction", "En instruction", "Terminé")
+    @dossiers_states_for_pie = {
+      "Brouillon" => stat.dossiers_brouillon,
+      "En construction" => stat.dossiers_en_construction,
+      "En instruction" => stat.dossiers_en_instruction,
+      "Terminé" => stat.dossiers_termines
+    }
 
     @procedures_cumulative = cumulative_hash(procedures, :published_at)
     @procedures_in_the_last_4_months = last_four_months_hash(procedures, :published_at)
 
-    @dossiers_cumulative = cumulative_hash(dossiers, :en_construction_at)
+    @dossiers_cumulative = stat.dossiers_cumulative
-    @dossiers_in_the_last_4_months = last_four_months_hash(dossiers, :en_construction_at)
+    @dossiers_in_the_last_4_months = stat.dossiers_in_the_last_4_months
 
     if administration_signed_in?
       @dossier_instruction_mean_time = Rails.cache.fetch("dossier_instruction_mean_time", expires_in: 1.day) do
@@ -118,25 +123,6 @@ class StatsController < ApplicationController
     }
   end
 
-  def dossiers_states
-    query = <<-EOF
-      SELECT
-        COUNT(*) FILTER ( WHERE state != 'brouillon' ) AS "not_brouillon",
-        COUNT(*) FILTER ( WHERE state != 'brouillon' and en_construction_at BETWEEN :one_month_ago AND :now ) AS "last_30_days_count",
-        COUNT(*) FILTER ( WHERE state != 'brouillon' and en_construction_at BETWEEN :two_months_ago AND :one_month_ago ) AS "previous_count",
-        COUNT(*) FILTER ( WHERE state = 'brouillon' ) AS "Brouillon",
-        COUNT(*) FILTER ( WHERE state = 'en_construction' ) AS "En construction",
-        COUNT(*) FILTER ( WHERE state = 'en_instruction' ) AS "En instruction",
-        COUNT(*) FILTER ( WHERE state in ('accepte', 'refuse', 'sans_suite') ) AS "Terminé"
-      FROM dossiers
-      WHERE hidden_at IS NULL
-    EOF
-
-    sanitized_query = ActiveRecord::Base.sanitize_sql([query, now: Time.zone.now, one_month_ago: 1.month.ago, two_months_ago: 2.months.ago])
-
-    Dossier.connection.select_all(sanitized_query).first
-  end
-
   def satisfaction_usagers
     legend = {
       Feedback.ratings.fetch(:unhappy) => "Mécontents",

app/jobs/update_stats_job.rb

@@ -0,0 +1,7 @@
+class UpdateStatsJob < CronJob
+  self.schedule_expression = "every 1 hour"
+
+  def perform(*args)
+    Stat.update_stats
+  end
+end

app/models/stat.rb

@@ -0,0 +1,91 @@
+# == Schema Information
+#
+# Table name: stats
+#
+#  id                                    :bigint           not null, primary key
+#  dossiers_brouillon                    :bigint           default(0)
+#  dossiers_cumulative                   :jsonb            not null
+#  dossiers_depose_avant_30_jours        :bigint           default(0)
+#  dossiers_deposes_entre_60_et_30_jours :bigint           default(0)
+#  dossiers_en_construction              :bigint           default(0)
+#  dossiers_en_instruction               :bigint           default(0)
+#  dossiers_in_the_last_4_months         :jsonb            not null
+#  dossiers_not_brouillon                :bigint           default(0)
+#  dossiers_termines                     :bigint           default(0)
+#  created_at                            :datetime         not null
+#  updated_at                            :datetime         not null
+#
+class Stat < ApplicationRecord
+  class << self
+    def update_stats
+      states = dossiers_states
+      stat = Stat.first || Stat.new
+
+      stat.update(
+        dossiers_en_construction: states['en_construction'],
+        dossiers_en_instruction: states['en_instruction'],
+        dossiers_brouillon: states['brouillon'],
+        dossiers_depose_avant_30_jours: states['dossiers_depose_avant_30_jours'],
+        dossiers_deposes_entre_60_et_30_jours: states['dossiers_deposes_entre_60_et_30_jours'],
+        dossiers_not_brouillon: states['not_brouillon'],
+        dossiers_termines: states['termines'],
+        dossiers_cumulative: cumulative_hash(Dossier.state_not_brouillon, :en_construction_at),
+        dossiers_in_the_last_4_months: last_four_months_hash(Dossier.state_not_brouillon, :en_construction_at)
+      )
+    end
+
+    private
+
+    def dossiers_states
+      query = <<-EOF
+      SELECT
+        COUNT(*) FILTER ( WHERE state != 'brouillon' ) AS "not_brouillon",
+        COUNT(*) FILTER ( WHERE state != 'brouillon' and en_construction_at BETWEEN :one_month_ago AND :now ) AS "dossiers_depose_avant_30_jours",
+        COUNT(*) FILTER ( WHERE state != 'brouillon' and en_construction_at BETWEEN :two_months_ago AND :one_month_ago ) AS "dossiers_deposes_entre_60_et_30_jours",
+        COUNT(*) FILTER ( WHERE state = 'brouillon' ) AS "brouillon",
+        COUNT(*) FILTER ( WHERE state = 'en_construction' ) AS "en_construction",
+        COUNT(*) FILTER ( WHERE state = 'en_instruction' ) AS "en_instruction",
+        COUNT(*) FILTER ( WHERE state in ('accepte', 'refuse', 'sans_suite') ) AS "termines"
+      FROM dossiers
+      WHERE hidden_at IS NULL
+      EOF
+
+      sanitized_query = ActiveRecord::Base.sanitize_sql([
+        query,
+        now: Time.zone.now,
+        one_month_ago: 1.month.ago,
+        two_months_ago: 2.months.ago
+      ])
+
+      Dossier.connection.select_all(sanitized_query).first
+    end
+
+    def last_four_months_hash(association, date_attribute)
+      min_date = 3.months.ago.beginning_of_month.to_date
+
+      association
+        .where(date_attribute => min_date..max_date)
+        .group("DATE_TRUNC('month', #{date_attribute})")
+        .count
+        .to_a
+        .sort_by { |a| a[0] }
+        .map { |e| [I18n.l(e.first, format: "%B %Y"), e.last] }
+    end
+
+    def cumulative_hash(association, date_attribute)
+      sum = 0
+      association
+        .where("#{date_attribute} < ?", max_date)
+        .group("DATE_TRUNC('month', #{date_attribute})")
+        .count
+        .to_a
+        .sort_by { |a| a[0] }
+        .map { |x, y| { x => (sum += y) } }
+        .reduce({}, :merge)
+    end
+
+    def max_date
+      Time.zone.now.beginning_of_month - 1.second
+    end
+  end
+end

db/migrate/20201002124154_create_stats.rb

@@ -0,0 +1,18 @@
+class CreateStats < ActiveRecord::Migration[6.0]
+  def change
+    create_table :stats do |t|
+      t.bigint :dossiers_not_brouillon, default: 0
+      t.bigint :dossiers_brouillon, default: 0
+      t.bigint :dossiers_en_construction, default: 0
+      t.bigint :dossiers_en_instruction, default: 0
+      t.bigint :dossiers_termines, default: 0
+      t.bigint :dossiers_depose_avant_30_jours, default: 0
+      t.bigint :dossiers_deposes_entre_60_et_30_jours, default: 0
+
+      t.jsonb :dossiers_cumulative, null: false, default: '{}'
+      t.jsonb :dossiers_in_the_last_4_months, null: false, default: '{}'
+
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_09_30_143755) do
+ActiveRecord::Schema.define(version: 2020_10_02_124154) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -586,6 +586,20 @@ ActiveRecord::Schema.define(version: 2020_09_30_143755) do
     t.index ["administrateur_id"], name: "index_services_on_administrateur_id"
   end
 
+  create_table "stats", force: :cascade do |t|
+    t.bigint "dossiers_not_brouillon", default: 0
+    t.bigint "dossiers_brouillon", default: 0
+    t.bigint "dossiers_en_construction", default: 0
+    t.bigint "dossiers_en_instruction", default: 0
+    t.bigint "dossiers_termines", default: 0
+    t.bigint "dossiers_depose_avant_30_jours", default: 0
+    t.bigint "dossiers_deposes_entre_60_et_30_jours", default: 0
+    t.jsonb "dossiers_cumulative", default: "{}", null: false
+    t.jsonb "dossiers_in_the_last_4_months", default: "{}", null: false
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+  end
+
   create_table "task_records", id: false, force: :cascade do |t|
     t.string "version", null: false
   end