Optimize Deployment related counters

Add index_deployments_on_id_and_status
Add index_deployments_on_user_id_status_and_created_at

changelogs/unreleased/208886-optimize-deployment-counters-related-to-the-deployment.yml

+---
+title: Optimize Deployment related counters
+merge_request: 26757
+author:
+type: performance

db/migrate/20200311084025_add_index_on_user_id_status_created_at_to_deployments.rb

+# frozen_string_literal: true
+
+class AddIndexOnUserIdStatusCreatedAtToDeployments < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :deployments, [:user_id, :status, :created_at]
+  end
+
+  def down
+    remove_concurrent_index :deployments, [:user_id, :status, :created_at]
+  end
+end

db/migrate/20200311094020_add_index_on_id_and_status_to_deployments.rb

+# frozen_string_literal: true
+
+class AddIndexOnIdAndStatusToDeployments < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :deployments, [:id, :status]
+  end
+
+  def down
+    remove_concurrent_index :deployments, [:id, :status]
+  end
+end

db/schema.rb

@@ -1409,6 +1409,7 @@ ActiveRecord::Schema.define(version: 2020_03_11_165635) do
     t.index ["environment_id", "id"], name: "index_deployments_on_environment_id_and_id"
     t.index ["environment_id", "iid", "project_id"], name: "index_deployments_on_environment_id_and_iid_and_project_id"
     t.index ["environment_id", "status"], name: "index_deployments_on_environment_id_and_status"
+    t.index ["id", "status"], name: "index_deployments_on_id_and_status"
     t.index ["id"], name: "partial_index_deployments_for_legacy_successful_deployments", where: "((finished_at IS NULL) AND (status = 2))"
     t.index ["project_id", "id"], name: "index_deployments_on_project_id_and_id", order: { id: :desc }
     t.index ["project_id", "iid"], name: "index_deployments_on_project_id_and_iid", unique: true
@@ -1417,6 +1418,7 @@ ActiveRecord::Schema.define(version: 2020_03_11_165635) do
     t.index ["project_id", "status"], name: "index_deployments_on_project_id_and_status"
     t.index ["project_id", "updated_at", "id"], name: "index_deployments_on_project_id_and_updated_at_and_id", order: { updated_at: :desc, id: :desc }
     t.index ["project_id"], name: "partial_index_deployments_for_project_id_and_tag", where: "(tag IS TRUE)"
+    t.index ["user_id", "status", "created_at"], name: "index_deployments_on_user_id_and_status_and_created_at"
   end
 
   create_table "description_versions", force: :cascade do |t|