Optimize projects slack with service counter

- usage ping is currently timing out on this query and we need
  to get it working.

changelogs/unreleased/208887-optimize-project-counters-with-slack-service.yml

+---
+title: Optimize Project related count with slack service
+merge_request: 26686
+author:
+type: performance

db/migrate/20200306192548_add_index_on_project_id_and_type_to_services.rb

+# frozen_string_literal: true
+
+class AddIndexOnProjectIdAndTypeToServices < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :services, [:project_id, :type]
+  end
+
+  def down
+    remove_concurrent_index :services, [:project_id, :type]
+  end
+end

db/migrate/20200306193236_add_index_on_id_and_creator_id_to_projects.rb

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

db/schema.rb

@@ -3473,6 +3473,7 @@ ActiveRecord::Schema.define(version: 2020_03_11_165635) do
     t.index ["creator_id", "created_at"], name: "index_projects_on_mirror_creator_id_created_at", where: "((mirror = true) AND (mirror_trigger_builds = true))"
     t.index ["creator_id"], name: "index_projects_on_creator_id"
     t.index ["description"], name: "index_projects_on_description_trigram", opclass: :gin_trgm_ops, using: :gin
+    t.index ["id", "creator_id"], name: "index_projects_on_id_and_creator_id"
     t.index ["id", "repository_storage", "last_repository_updated_at"], name: "idx_projects_on_repository_storage_last_repository_updated_at"
     t.index ["id"], name: "index_on_id_partial_with_legacy_storage", where: "((storage_version < 2) OR (storage_version IS NULL))"
     t.index ["id"], name: "index_projects_on_id_partial_for_visibility", unique: true, where: "(visibility_level = ANY (ARRAY[10, 20]))"
@@ -3944,7 +3945,7 @@ ActiveRecord::Schema.define(version: 2020_03_11_165635) do
     t.boolean "comment_on_event_enabled", default: true, null: false
     t.boolean "template", default: false
     t.boolean "instance", default: false, null: false
-    t.index ["project_id"], name: "index_services_on_project_id"
+    t.index ["project_id", "type"], name: "index_services_on_project_id_and_type"
     t.index ["template"], name: "index_services_on_template"
     t.index ["type", "instance"], name: "index_services_on_type_and_instance", unique: true, where: "(instance IS TRUE)"
     t.index ["type", "template"], name: "index_services_on_type_and_template", unique: true, where: "(template IS TRUE)"