From 0206476ae2a2d659fd0fb42338050253a9a91439 Mon Sep 17 00:00:00 2001 From: Sean McGivern Date: Thu, 7 Jun 2018 12:14:27 +0100 Subject: [PATCH] Fix some N+1s when calculating notification recipients First N+1: we may have loaded a user's notification settings already, but not have loaded their sources. Because we're iterating through, we'd potentially load sources that are completely unrelated, just because they belong to this user. Second N+1: we do a separate query for each user who could be subscribed to or unsubcribed from the target. It's actually more efficient in this case to get all subscriptions at once, as we will need to check most of them. We can fix both by the slightly unpleasant means of checking IDs manually, rather than object equality. --- app/models/notification_recipient.rb | 2 +- app/models/user.rb | 5 ++- .../n-plus-one-notification-recipients.yml | 5 +++ .../notification_recipient_service_spec.rb | 36 +++++++++++++++++++ 4 files changed, 46 insertions(+), 2 deletions(-) create mode 100644 changelogs/unreleased/n-plus-one-notification-recipients.yml create mode 100644 spec/services/notification_recipient_service_spec.rb diff --git a/app/models/notification_recipient.rb b/app/models/notification_recipient.rb index 2c3580bbdc6..79458bd048a 100644 --- a/app/models/notification_recipient.rb +++ b/app/models/notification_recipient.rb @@ -64,7 +64,7 @@ class NotificationRecipient return false unless @target return false unless @target.respond_to?(:subscriptions) - subscription = @target.subscriptions.find_by_user_id(@user.id) + subscription = @target.subscriptions.find { |subscription| subscription.user_id == @user.id } subscription && !subscription.subscribed end diff --git a/app/models/user.rb b/app/models/user.rb index e219ab800ad..8e0dc91b2a7 100644 --- a/app/models/user.rb +++ b/app/models/user.rb @@ -1038,7 +1038,10 @@ class User < ActiveRecord::Base def notification_settings_for(source) if notification_settings.loaded? - notification_settings.find { |notification| notification.source == source } + notification_settings.find do |notification| + notification.source_type == source.class.base_class.name && + notification.source_id == source.id + end else notification_settings.find_or_initialize_by(source: source) end diff --git a/changelogs/unreleased/n-plus-one-notification-recipients.yml b/changelogs/unreleased/n-plus-one-notification-recipients.yml new file mode 100644 index 00000000000..91c31e4c930 --- /dev/null +++ b/changelogs/unreleased/n-plus-one-notification-recipients.yml @@ -0,0 +1,5 @@ +--- +title: Fix some sources of excessive query counts when calculating notification recipients +merge_request: +author: +type: performance diff --git a/spec/services/notification_recipient_service_spec.rb b/spec/services/notification_recipient_service_spec.rb new file mode 100644 index 00000000000..340d4585e0c --- /dev/null +++ b/spec/services/notification_recipient_service_spec.rb @@ -0,0 +1,36 @@ +require 'spec_helper' + +describe NotificationRecipientService do + let(:service) { described_class } + let(:assignee) { create(:user) } + let(:project) { create(:project, :public) } + let(:other_projects) { create_list(:project, 5, :public) } + + describe '#build_new_note_recipients' do + let(:issue) { create(:issue, project: project, assignees: [assignee]) } + let(:note) { create(:note_on_issue, noteable: issue, project_id: issue.project_id) } + + def create_watcher + watcher = create(:user) + create(:notification_setting, project: project, user: watcher, level: :watch) + + other_projects.each do |other_project| + create(:notification_setting, project: other_project, user: watcher, level: :watch) + end + end + + it 'avoids N+1 queries' do + create_watcher + + service.build_new_note_recipients(note) + + control_count = ActiveRecord::QueryRecorder.new do + service.build_new_note_recipients(note) + end + + create_watcher + + expect { service.build_new_note_recipients(note) }.not_to exceed_query_limit(control_count) + end + end +end