Fix performance on instances list in admin UI (#15282)

- Reduce duplicate queries
- Remove n+1 queries
- Add accounts count to detailed view
- Add separate action log entry for updating existing domain blocks

27 files changed, 326 insertions, 166 deletions

diff --git a/Gemfile b/Gemfile
index 63becb7cc..3aee5d7cc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -82,6 +82,7 @@ gem 'mario-redis-lock', '~> 1.2', require: 'redis_lock'
 gem 'rqrcode', '~> 1.1'
 gem 'ruby-progressbar', '~> 1.10'
 gem 'sanitize', '~> 5.2'
+gem 'scenic', '~> 1.5'
 gem 'sidekiq', '~> 6.1'
 gem 'sidekiq-scheduler', '~> 3.0'
 gem 'sidekiq-unique-jobs', '~> 6.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index f7192d084..c4c8d9904 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -561,6 +561,9 @@ GEM
       crass (~> 1.0.2)
       nokogiri (>= 1.8.0)
       nokogumbo (~> 2.0)
+    scenic (1.5.4)
+      activerecord (>= 4.0.0)
+      railties (>= 4.0.0)
     securecompare (1.0.0)
     semantic_range (2.3.0)
     sidekiq (6.1.2)
@@ -782,6 +785,7 @@ DEPENDENCIES
   rubocop-rails (~> 2.8)
   ruby-progressbar (~> 1.10)
   sanitize (~> 5.2)
+  scenic (~> 1.5)
   sidekiq (~> 6.1)
   sidekiq-bulk (~> 0.2.0)
   sidekiq-scheduler (~> 3.0)
diff --git a/app/controllers/admin/domain_blocks_controller.rb b/app/controllers/admin/domain_blocks_controller.rb
index 74a36b79c..6a5b41a74 100644
--- a/app/controllers/admin/domain_blocks_controller.rb
+++ b/app/controllers/admin/domain_blocks_controller.rb
@@ -29,6 +29,7 @@ module Admin
           @domain_block = existing_domain_block
           @domain_block.update(resource_params)
         end
+
         if @domain_block.save
           DomainBlockWorker.perform_async(@domain_block.id)
           log_action :create, @domain_block
@@ -40,7 +41,7 @@ module Admin
     end
 
     def update
-      authorize :domain_block, :create?
+      authorize :domain_block, :update?
 
       @domain_block.update(update_params)
 
@@ -48,7 +49,7 @@ module Admin
 
       if @domain_block.save
         DomainBlockWorker.perform_async(@domain_block.id, severity_changed)
-        log_action :create, @domain_block
+        log_action :update, @domain_block
         redirect_to admin_instances_path(limited: '1'), notice: I18n.t('admin.domain_blocks.created_msg')
       else
         render :edit
diff --git a/app/controllers/admin/instances_controller.rb b/app/controllers/admin/instances_controller.rb
index 1790becbf..b5918d231 100644
--- a/app/controllers/admin/instances_controller.rb
+++ b/app/controllers/admin/instances_controller.rb
@@ -2,65 +2,31 @@
 
 module Admin
   class InstancesController < BaseController
-    before_action :set_domain_block, only: :show
-    before_action :set_domain_allow, only: :show
+    before_action :set_instances, only: :index
     before_action :set_instance, only: :show
 
     def index
       authorize :instance, :index?
-
-      @instances = ordered_instances
     end
 
     def show
       authorize :instance, :show?
-
-      @following_count = Follow.where(account: Account.where(domain: params[:id])).count
-      @followers_count = Follow.where(target_account: Account.where(domain: params[:id])).count
-      @reports_count   = Report.where(target_account: Account.where(domain: params[:id])).count
-      @blocks_count    = Block.where(target_account: Account.where(domain: params[:id])).count
-      @available       = DeliveryFailureTracker.available?(params[:id])
-      @media_storage   = MediaAttachment.where(account: Account.where(domain: params[:id])).sum(:file_file_size)
-      @private_comment = @domain_block&.private_comment
-      @public_comment  = @domain_block&.public_comment
     end
 
     private
 
-    def set_domain_block
-      @domain_block = DomainBlock.rule_for(params[:id])
-    end
-
-    def set_domain_allow
-      @domain_allow = DomainAllow.rule_for(params[:id])
-    end
-
     def set_instance
-      resource   = Account.by_domain_accounts.find_by(domain: params[:id])
-      resource ||= @domain_block
-      resource ||= @domain_allow
+      @instance = Instance.find(params[:id])
+    end
 
-      if resource
-        @instance = Instance.new(resource)
-      else
-        not_found
-      end
+    def set_instances
+      @instances = filtered_instances.page(params[:page])
     end
 
     def filtered_instances
       InstanceFilter.new(whitelist_mode? ? { allowed: true } : filter_params).results
     end
 
-    def paginated_instances
-      filtered_instances.page(params[:page])
-    end
-
-    helper_method :paginated_instances
-
-    def ordered_instances
-      paginated_instances.map { |resource| Instance.new(resource) }
-    end
-
     def filter_params
       params.slice(*InstanceFilter::KEYS).permit(*InstanceFilter::KEYS)
     end
diff --git a/app/controllers/api/v1/instances/peers_controller.rb b/app/controllers/api/v1/instances/peers_controller.rb
index 9fa440935..2877fec52 100644
--- a/app/controllers/api/v1/instances/peers_controller.rb
+++ b/app/controllers/api/v1/instances/peers_controller.rb
@@ -8,7 +8,7 @@ class Api::V1::Instances::PeersController < Api::BaseController
 
   def index
     expires_in 1.day, public: true
-    render_with_cache(expires_in: 1.day) { Account.remote.domains }
+    render_with_cache(expires_in: 1.day) { Instance.where.not(domain: DomainBlock.select(:domain)).pluck(:domain) }
   end
 
   private
diff --git a/app/models/account.rb b/app/models/account.rb
index ed11a514d..e21b353e9 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -67,6 +67,7 @@ class Account < ApplicationRecord
   include Paginable
   include AccountCounters
   include DomainNormalizable
+  include DomainMaterializable
   include AccountMerging
 
   TRUST_LEVELS = {
@@ -103,7 +104,6 @@ class Account < ApplicationRecord
   scope :bots, -> { where(actor_type: %w(Application Service)) }
   scope :groups, -> { where(actor_type: 'Group') }
   scope :alphabetic, -> { order(domain: :asc, username: :asc) }
-  scope :by_domain_accounts, -> { group(:domain).select(:domain, 'COUNT(*) AS accounts_count').order('accounts_count desc') }
   scope :matches_username, ->(value) { where(arel_table[:username].matches("#{value}%")) }
   scope :matches_display_name, ->(value) { where(arel_table[:display_name].matches("#{value}%")) }
   scope :matches_domain, ->(value) { where(arel_table[:domain].matches("%#{value}%")) }
@@ -438,10 +438,6 @@ class Account < ApplicationRecord
       super - %w(statuses_count following_count followers_count)
     end
 
-    def domains
-      reorder(nil).pluck(Arel.sql('distinct accounts.domain'))
-    end
-
     def inboxes
       urls = reorder(nil).where(protocol: :activitypub).group(:preferred_inbox_url).pluck(Arel.sql("coalesce(nullif(accounts.shared_inbox_url, ''), accounts.inbox_url) AS preferred_inbox_url"))
       DeliveryFailureTracker.without_unavailable(urls)
diff --git a/app/models/concerns/domain_materializable.rb b/app/models/concerns/domain_materializable.rb
new file mode 100644
index 000000000..88337f8c0
--- /dev/null
+++ b/app/models/concerns/domain_materializable.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module DomainMaterializable
+  extend ActiveSupport::Concern
+
+  included do
+    after_create_commit :refresh_instances_view
+  end
+
+  def refresh_instances_view
+    Instance.refresh unless domain.nil? || Instance.where(domain: domain).exists?
+  end
+end
diff --git a/app/models/domain_allow.rb b/app/models/domain_allow.rb
index 5fe0e3a29..4b0a89c18 100644
--- a/app/models/domain_allow.rb
+++ b/app/models/domain_allow.rb
@@ -12,6 +12,7 @@
 
 class DomainAllow < ApplicationRecord
   include DomainNormalizable
+  include DomainMaterializable
 
   validates :domain, presence: true, uniqueness: true, domain: true
 
diff --git a/app/models/domain_block.rb b/app/models/domain_block.rb
index 2b18e01fa..829d7583b 100644
--- a/app/models/domain_block.rb
+++ b/app/models/domain_block.rb
@@ -16,6 +16,7 @@
 
 class DomainBlock < ApplicationRecord
   include DomainNormalizable
+  include DomainMaterializable
 
   enum severity: [:silence, :suspend, :noop]
 
diff --git a/app/models/instance.rb b/app/models/instance.rb
index 3c740f8a2..29be03662 100644
--- a/app/models/instance.rb
+++ b/app/models/instance.rb
@@ -1,26 +1,63 @@
 # frozen_string_literal: true
+# == Schema Information
+#
+# Table name: instances
+#
+#  domain         :string           primary key
+#  accounts_count :bigint(8)
+#
 
-class Instance
-  include ActiveModel::Model
+class Instance < ApplicationRecord
+  self.primary_key = :domain
 
-  attr_accessor :domain, :accounts_count, :domain_block
+  has_many :accounts, foreign_key: :domain, primary_key: :domain
 
-  def initialize(resource)
-    @domain         = resource.domain
-    @accounts_count = resource.respond_to?(:accounts_count) ? resource.accounts_count : nil
-    @domain_block   = resource.is_a?(DomainBlock) ? resource : DomainBlock.rule_for(domain)
-    @domain_allow   = resource.is_a?(DomainAllow) ? resource : DomainAllow.rule_for(domain)
+  belongs_to :domain_block, foreign_key: :domain, primary_key: :domain
+  belongs_to :domain_allow, foreign_key: :domain, primary_key: :domain
+
+  scope :matches_domain, ->(value) { where(arel_table[:domain].matches("%#{value}%")) }
+
+  def self.refresh
+    Scenic.database.refresh_materialized_view(table_name, concurrently: true, cascade: false)
   end
 
-  def countable?
-    @accounts_count.present?
+  def readonly?
+    true
   end
 
-  def to_param
-    domain
+  def delivery_failure_tracker
+    @delivery_failure_tracker ||= DeliveryFailureTracker.new(domain)
+  end
+
+  def following_count
+    @following_count ||= Follow.where(account: accounts).count
+  end
+
+  def followers_count
+    @followers_count ||= Follow.where(target_account: accounts).count
+  end
+
+  def reports_count
+    @reports_count ||= Report.where(target_account: accounts).count
   end
 
-  def cache_key
+  def blocks_count
+    @blocks_count ||= Block.where(target_account: accounts).count
+  end
+
+  def public_comment
+    domain_block&.public_comment
+  end
+
+  def private_comment
+    domain_block&.private_comment
+  end
+
+  def media_storage
+    @media_storage ||= MediaAttachment.where(account: accounts).sum(:file_file_size)
+  end
+
+  def to_param
     domain
   end
 end
diff --git a/app/models/instance_filter.rb b/app/models/instance_filter.rb
index 9c467bc27..0598d8fea 100644
--- a/app/models/instance_filter.rb
+++ b/app/models/instance_filter.rb
@@ -13,18 +13,27 @@ class InstanceFilter
   end
 
   def results
-    if params[:limited].present?
-      scope = DomainBlock
-      scope = scope.matches_domain(params[:by_domain]) if params[:by_domain].present?
-      scope.order(id: :desc)
-    elsif params[:allowed].present?
-      scope = DomainAllow
-      scope = scope.matches_domain(params[:by_domain]) if params[:by_domain].present?
-      scope.order(id: :desc)
+    scope = Instance.includes(:domain_block, :domain_allow).order(accounts_count: :desc)
+
+    params.each do |key, value|
+      scope.merge!(scope_for(key, value.to_s.strip)) if value.present?
+    end
+
+    scope
+  end
+
+  private
+
+  def scope_for(key, value)
+    case key.to_s
+    when 'limited'
+      Instance.joins(:domain_block).reorder(Arel.sql('domain_blocks.id desc'))
+    when 'allowed'
+      Instance.joins(:domain_allow).reorder(Arel.sql('domain_allows.id desc'))
+    when 'by_domain'
+      Instance.matches_domain(value)
     else
-      scope = Account.remote
-      scope = scope.matches_domain(params[:by_domain]) if params[:by_domain].present?
-      scope.by_domain_accounts
+      raise "Unknown filter: #{key}"
     end
   end
 end
diff --git a/app/models/unavailable_domain.rb b/app/models/unavailable_domain.rb
index e2918b586..5e8870bde 100644
--- a/app/models/unavailable_domain.rb
+++ b/app/models/unavailable_domain.rb
@@ -12,6 +12,8 @@
 class UnavailableDomain < ApplicationRecord
   include DomainNormalizable
 
+  validates :domain, presence: true, uniqueness: true
+
   after_commit :reset_cache!
 
   private
diff --git a/app/policies/domain_block_policy.rb b/app/policies/domain_block_policy.rb
index 47c0a81af..543259cce 100644
--- a/app/policies/domain_block_policy.rb
+++ b/app/policies/domain_block_policy.rb
@@ -13,6 +13,10 @@ class DomainBlockPolicy < ApplicationPolicy
     admin?
   end
 
+  def update?
+    admin?
+  end
+
   def destroy?
     admin?
   end
diff --git a/app/presenters/instance_presenter.rb b/app/presenters/instance_presenter.rb
index c150bf742..1bfdd40ac 100644
--- a/app/presenters/instance_presenter.rb
+++ b/app/presenters/instance_presenter.rb
@@ -29,7 +29,7 @@ class InstancePresenter
   end
 
   def domain_count
-    Rails.cache.fetch('distinct_domain_count') { Account.distinct.count(:domain) }
+    Rails.cache.fetch('distinct_domain_count') { Instance.count }
   end
 
   def sample_accounts
diff --git a/app/views/admin/instances/_instance.html.haml b/app/views/admin/instances/_instance.html.haml
new file mode 100644
index 000000000..188d0d984
--- /dev/null
+++ b/app/views/admin/instances/_instance.html.haml
@@ -0,0 +1,25 @@
+.directory__tag
+  = link_to admin_instance_path(instance) do
+    %h4
+      = instance.domain
+      %small
+        - if instance.domain_block
+          - first_item = true
+          - if !instance.domain_block.noop?
+            = t("admin.domain_blocks.severity.#{instance.domain_block.severity}")
+            - first_item = false
+          - unless instance.domain_block.suspend?
+            - if instance.domain_block.reject_media?
+              - unless first_item
+                &bull;
+              = t('admin.domain_blocks.rejecting_media')
+              - first_item = false
+            - if instance.domain_block.reject_reports?
+              - unless first_item
+                &bull;
+              = t('admin.domain_blocks.rejecting_reports')
+        - elsif whitelist_mode?
+          = t('admin.accounts.whitelisted')
+        - else
+          = t('admin.accounts.no_limits_imposed')
+    .trends__item__current{ title: t('admin.instances.known_accounts', count: instance.accounts_count) }= number_to_human instance.accounts_count, strip_insignificant_zeros: true
diff --git a/app/views/admin/instances/index.html.haml b/app/views/admin/instances/index.html.haml
index 696ba3c7f..5f20e7ec0 100644
--- a/app/views/admin/instances/index.html.haml
+++ b/app/views/admin/instances/index.html.haml
@@ -32,32 +32,10 @@
 
 %hr.spacer/
 
-- @instances.each do |instance|
-  .directory__tag
-    = link_to admin_instance_path(instance) do
-      %h4
-        = instance.domain
-        %small
-          - if instance.domain_block
-            - first_item = true
-            - if !instance.domain_block.noop?
-              = t("admin.domain_blocks.severity.#{instance.domain_block.severity}")
-              - first_item = false
-            - unless instance.domain_block.suspend?
-              - if instance.domain_block.reject_media?
-                - unless first_item
-                  &bull;
-                = t('admin.domain_blocks.rejecting_media')
-                - first_item = false
-              - if instance.domain_block.reject_reports?
-                - unless first_item
-                  &bull;
-                = t('admin.domain_blocks.rejecting_reports')
-          - elsif whitelist_mode?
-            = t('admin.accounts.whitelisted')
-          - else
-            = t('admin.accounts.no_limits_imposed')
-      - if instance.countable?
-        .trends__item__current{ title: t('admin.instances.known_accounts', count: instance.accounts_count) }= number_to_human instance.accounts_count, strip_insignificant_zeros: true
-
-= paginate paginated_instances
+- if @instances.empty?
+  %div.muted-hint.center-text
+    = t 'admin.instances.empty'
+- else
+  = render @instances
+
+= paginate @instances
diff --git a/app/views/admin/instances/show.html.haml b/app/views/admin/instances/show.html.haml
index 92e14c0df..0b9382771 100644
--- a/app/views/admin/instances/show.html.haml
+++ b/app/views/admin/instances/show.html.haml
@@ -3,57 +3,59 @@
 
 .dashboard__counters
   %div
+    = link_to admin_accounts_path(remote: '1', by_domain: @instance.domain) do
+      .dashboard__counters__num= number_with_delimiter @instance.accounts_count
+      .dashboard__counters__label= t 'admin.accounts.title'
+  %div
+    = link_to admin_reports_path(by_target_domain: @instance.domain) do
+      .dashboard__counters__num= number_with_delimiter @instance.reports_count
+      .dashboard__counters__label= t 'admin.instances.total_reported'
+  %div
     %div
-      .dashboard__counters__num= number_with_delimiter @following_count
-      .dashboard__counters__label= t 'admin.instances.total_followed_by_them'
+      .dashboard__counters__num= number_to_human_size @instance.media_storage
+      .dashboard__counters__label= t 'admin.instances.total_storage'
   %div
     %div
-      .dashboard__counters__num= number_with_delimiter @followers_count
-      .dashboard__counters__label= t 'admin.instances.total_followed_by_us'
+      .dashboard__counters__num= number_with_delimiter @instance.following_count
+      .dashboard__counters__label= t 'admin.instances.total_followed_by_them'
   %div
     %div
-      .dashboard__counters__num= number_to_human_size @media_storage
-      .dashboard__counters__label= t 'admin.instances.total_storage'
+      .dashboard__counters__num= number_with_delimiter @instance.followers_count
+      .dashboard__counters__label= t 'admin.instances.total_followed_by_us'
   %div
     %div
-      .dashboard__counters__num= number_with_delimiter @blocks_count
+      .dashboard__counters__num= number_with_delimiter @instance.blocks_count
       .dashboard__counters__label= t 'admin.instances.total_blocked_by_us'
-  %div
-    = link_to admin_reports_path(by_target_domain: @instance.domain) do
-      .dashboard__counters__num= number_with_delimiter @reports_count
-      .dashboard__counters__label= t 'admin.instances.total_reported'
+
   %div
     %div
       .dashboard__counters__num
-        - if @available
+        - if @instance.delivery_failure_tracker.available?
           = fa_icon 'check'
         - else
           = fa_icon 'times'
       .dashboard__counters__label= t 'admin.instances.delivery_available'
 
-- if @private_comment.present?
+- if @instance.private_comment.present?
   .speech-bubble
     .speech-bubble__bubble
-      = simple_format(h(@private_comment))
+      = simple_format(h(@instance.private_comment))
     .speech-bubble__owner= t 'admin.instances.private_comment'
 
-- if @public_comment.present?
+- if @instance.public_comment.present?
   .speech-bubble
     .speech-bubble__bubble
-      = simple_format(h(@public_comment))
+      = simple_format(h(@instance.public_comment))
     .speech-bubble__owner= t 'admin.instances.public_comment'
 
 %hr.spacer/
 
 %div.action-buttons
   %div
-    = link_to t('admin.accounts.title'), admin_accounts_path(remote: '1', by_domain: @instance.domain), class: 'button'
-
-  %div
-    - if @domain_allow
-      = link_to t('admin.domain_allows.undo'), admin_domain_allow_path(@domain_allow), class: 'button button--destructive', data: { confirm: t('admin.accounts.are_you_sure'), method: :delete }
-    - elsif @domain_block
-      = link_to t('admin.domain_blocks.edit'), edit_admin_domain_block_path(@domain_block), class: 'button'
-      = link_to t('admin.domain_blocks.undo'), admin_domain_block_path(@domain_block), class: 'button'
+    - if @instance.domain_allow
+      = link_to t('admin.domain_allows.undo'), admin_domain_allow_path(@instance.domain_allow), class: 'button button--destructive', data: { confirm: t('admin.accounts.are_you_sure'), method: :delete }
+    - elsif @instance.domain_block
+      = link_to t('admin.domain_blocks.edit'), edit_admin_domain_block_path(@instance.domain_block), class: 'button'
+      = link_to t('admin.domain_blocks.undo'), admin_domain_block_path(@instance.domain_block), class: 'button'
     - else
       = link_to t('admin.domain_blocks.add_new'), new_admin_domain_block_path(_domain: @instance.domain), class: 'button'
diff --git a/app/workers/scheduler/instance_refresh_scheduler.rb b/app/workers/scheduler/instance_refresh_scheduler.rb
new file mode 100644
index 000000000..917404bec
--- /dev/null
+++ b/app/workers/scheduler/instance_refresh_scheduler.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class Scheduler::InstanceRefreshScheduler
+  include Sidekiq::Worker
+
+  sidekiq_options lock: :until_executed, retry: 0
+
+  def perform
+    Instance.refresh
+  end
+end
diff --git a/config/brakeman.ignore b/config/brakeman.ignore
index baa993c78..dcbfd02b4 100644
--- a/config/brakeman.ignore
+++ b/config/brakeman.ignore
@@ -103,6 +103,37 @@
       "note": ""
     },
     {
+      "warning_type": "Dynamic Render Path",
+      "warning_code": 15,
+      "fingerprint": "4704e8093e3e0561bf705f892e8fc6780419f8255f4440b1c0afd09339bd6446",
+      "check_name": "Render",
+      "message": "Render path contains parameter value",
+      "file": "app/views/admin/instances/index.html.haml",
+      "line": 39,
+      "link": "https://brakemanscanner.org/docs/warning_types/dynamic_render_path/",
+      "code": "render(action => filtered_instances.page(params[:page]), {})",
+      "render_path": [
+        {
+          "type": "controller",
+          "class": "Admin::InstancesController",
+          "method": "index",
+          "line": 10,
+          "file": "app/controllers/admin/instances_controller.rb",
+          "rendered": {
+            "name": "admin/instances/index",
+            "file": "app/views/admin/instances/index.html.haml"
+          }
+        }
+      ],
+      "location": {
+        "type": "template",
+        "template": "admin/instances/index"
+      },
+      "user_input": "params[:page]",
+      "confidence": "Weak",
+      "note": ""
+    },
+    {
       "warning_type": "Redirect",
       "warning_code": 18,
       "fingerprint": "5fad11cd67f905fab9b1d5739d01384a1748ebe78c5af5ac31518201925265a7",
@@ -125,6 +156,26 @@
     {
       "warning_type": "SQL Injection",
       "warning_code": 0,
+      "fingerprint": "6e4051854bb62e2ddbc671f82d6c2328892e1134b8b28105ecba9b0122540714",
+      "check_name": "SQL",
+      "message": "Possible SQL injection",
+      "file": "app/models/account.rb",
+      "line": 491,
+      "link": "https://brakemanscanner.org/docs/warning_types/sql_injection/",
+      "code": "find_by_sql([\"          WITH first_degree AS (\\n            SELECT target_account_id\\n            FROM follows\\n            WHERE account_id = ?\\n            UNION ALL\\n            SELECT ?\\n          )\\n          SELECT\\n            accounts.*,\\n            (count(f.id) + 1) * ts_rank_cd(#{textsearch}, #{query}, 32) AS rank\\n          FROM accounts\\n          LEFT OUTER JOIN follows AS f ON (accounts.id = f.account_id AND f.target_account_id = ?)\\n          WHERE accounts.id IN (SELECT * FROM first_degree)\\n            AND #{query} @@ #{textsearch}\\n            AND accounts.suspended_at IS NULL\\n            AND accounts.moved_to_account_id IS NULL\\n          GROUP BY accounts.id\\n          ORDER BY rank DESC\\n          LIMIT ? OFFSET ?\\n\".squish, account.id, account.id, account.id, limit, offset])",
+      "render_path": null,
+      "location": {
+        "type": "method",
+        "class": "Account",
+        "method": "advanced_search_for"
+      },
+      "user_input": "textsearch",
+      "confidence": "Medium",
+      "note": ""
+    },
+    {
+      "warning_type": "SQL Injection",
+      "warning_code": 0,
       "fingerprint": "6f075c1484908e3ec9bed21ab7cf3c7866be8da3881485d1c82e13093aefcbd7",
       "check_name": "SQL",
       "message": "Possible SQL injection",
@@ -163,23 +214,23 @@
       "note": ""
     },
     {
-      "warning_type": "Mass Assignment",
-      "warning_code": 105,
-      "fingerprint": "8f63dec68951d9bcf7eddb15af9392b2e1333003089c41fb76688dfd3579f394",
-      "check_name": "PermitAttributes",
-      "message": "Potentially dangerous key allowed for mass assignment",
-      "file": "app/controllers/api/v1/crypto/deliveries_controller.rb",
-      "line": 23,
-      "link": "https://brakemanscanner.org/docs/warning_types/mass_assignment/",
-      "code": "params.require(:device).permit(:account_id, :device_id, :type, :body, :hmac)",
+      "warning_type": "SQL Injection",
+      "warning_code": 0,
+      "fingerprint": "9251d682c4e2840e1b2fea91e7d758efe2097ecb7f6255c065e3750d25eb178c",
+      "check_name": "SQL",
+      "message": "Possible SQL injection",
+      "file": "app/models/account.rb",
+      "line": 460,
+      "link": "https://brakemanscanner.org/docs/warning_types/sql_injection/",
+      "code": "find_by_sql([\"        SELECT\\n          accounts.*,\\n          ts_rank_cd(#{textsearch}, #{query}, 32) AS rank\\n        FROM accounts\\n        WHERE #{query} @@ #{textsearch}\\n          AND accounts.suspended_at IS NULL\\n          AND accounts.moved_to_account_id IS NULL\\n        ORDER BY rank DESC\\n        LIMIT ? OFFSET ?\\n\".squish, limit, offset])",
       "render_path": null,
       "location": {
         "type": "method",
-        "class": "Api::V1::Crypto::DeliveriesController",
-        "method": "resource_params"
+        "class": "Account",
+        "method": "search_for"
       },
-      "user_input": ":account_id",
-      "confidence": "High",
+      "user_input": "textsearch",
+      "confidence": "Medium",
       "note": ""
     },
     {
@@ -274,6 +325,26 @@
       "note": ""
     },
     {
+      "warning_type": "SQL Injection",
+      "warning_code": 0,
+      "fingerprint": "e21d8fee7a5805761679877ca35ed1029c64c45ef3b4012a30262623e1ba8bb9",
+      "check_name": "SQL",
+      "message": "Possible SQL injection",
+      "file": "app/models/account.rb",
+      "line": 507,
+      "link": "https://brakemanscanner.org/docs/warning_types/sql_injection/",
+      "code": "find_by_sql([\"          SELECT\\n            accounts.*,\\n            (count(f.id) + 1) * ts_rank_cd(#{textsearch}, #{query}, 32) AS rank\\n          FROM accounts\\n          LEFT OUTER JOIN follows AS f ON (accounts.id = f.account_id AND f.target_account_id = ?) OR (accounts.id = f.target_account_id AND f.account_id = ?)\\n          WHERE #{query} @@ #{textsearch}\\n            AND accounts.suspended_at IS NULL\\n            AND accounts.moved_to_account_id IS NULL\\n          GROUP BY accounts.id\\n          ORDER BY rank DESC\\n          LIMIT ? OFFSET ?\\n\".squish, account.id, account.id, limit, offset])",
+      "render_path": null,
+      "location": {
+        "type": "method",
+        "class": "Account",
+        "method": "advanced_search_for"
+      },
+      "user_input": "textsearch",
+      "confidence": "Medium",
+      "note": ""
+    },
+    {
       "warning_type": "Mass Assignment",
       "warning_code": 105,
       "fingerprint": "e867661b2c9812bc8b75a5df12b28e2a53ab97015de0638b4e732fe442561b28",
@@ -294,6 +365,6 @@
       "note": ""
     }
   ],
-  "updated": "2020-06-01 18:18:02 +0200",
-  "brakeman_version": "4.8.0"
+  "updated": "2020-12-07 01:17:13 +0100",
+  "brakeman_version": "4.10.0"
 }
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 59f561aa3..f89f50e4d 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -255,6 +255,7 @@ en:
         unsuspend_account: Unsuspend Account
         update_announcement: Update Announcement
         update_custom_emoji: Update Custom Emoji
+        update_domain_block: Update Domain Block
         update_status: Update Status
       actions:
         assigned_to_self_report: "%{name} assigned report %{target} to themselves"
@@ -295,6 +296,7 @@ en:
         unsuspend_account: "%{name} unsuspended %{target}'s account"
         update_announcement: "%{name} updated announcement %{target}"
         update_custom_emoji: "%{name} updated emoji %{target}"
+        update_domain_block: "%{name} updated domain block for %{target}"
         update_status: "%{name} updated status by %{target}"
       deleted_status: "(deleted status)"
       empty: No logs found.
@@ -437,6 +439,7 @@ en:
     instances:
       by_domain: Domain
       delivery_available: Delivery is available
+      empty: No domains found.
       known_accounts:
         one: "%{count} known account"
         other: "%{count} known accounts"
diff --git a/config/sidekiq.yml b/config/sidekiq.yml
index 5de25de23..a71c1098e 100644
--- a/config/sidekiq.yml
+++ b/config/sidekiq.yml
@@ -36,3 +36,6 @@
   pghero_scheduler:
     cron: '0 0 * * *'
     class: Scheduler::PgheroScheduler
+  instance_refresh_scheduler:
+    cron: '0 * * * *'
+    class: Scheduler::InstanceRefreshScheduler
diff --git a/db/migrate/20201206004238_create_instances.rb b/db/migrate/20201206004238_create_instances.rb
new file mode 100644
index 000000000..a4b866894
--- /dev/null
+++ b/db/migrate/20201206004238_create_instances.rb
@@ -0,0 +1,9 @@
+class CreateInstances < ActiveRecord::Migration[5.2]
+  def change
+    create_view :instances, materialized: true
+
+    # To be able to refresh the view concurrently,
+    # at least one unique index is required
+    safety_assured { add_index :instances, :domain, unique: true }
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 873c37f67..2f9d369be 100644
--- a/db/schema.rb
+++ b/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_10_17_234926) do
+ActiveRecord::Schema.define(version: 2020_12_06_004238) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -1045,4 +1045,29 @@ ActiveRecord::Schema.define(version: 2020_10_17_234926) do
   add_foreign_key "web_push_subscriptions", "users", on_delete: :cascade
   add_foreign_key "web_settings", "users", name: "fk_11910667b2", on_delete: :cascade
   add_foreign_key "webauthn_credentials", "users"
+
+  create_view "instances", materialized: true, sql_definition: <<-SQL
+      WITH domain_counts(domain, accounts_count) AS (
+           SELECT accounts.domain,
+              count(*) AS accounts_count
+             FROM accounts
+            WHERE (accounts.domain IS NOT NULL)
+            GROUP BY accounts.domain
+          )
+   SELECT domain_counts.domain,
+      domain_counts.accounts_count
+     FROM domain_counts
+  UNION
+   SELECT domain_blocks.domain,
+      COALESCE(domain_counts.accounts_count, (0)::bigint) AS accounts_count
+     FROM (domain_blocks
+       LEFT JOIN domain_counts ON (((domain_counts.domain)::text = (domain_blocks.domain)::text)))
+  UNION
+   SELECT domain_allows.domain,
+      COALESCE(domain_counts.accounts_count, (0)::bigint) AS accounts_count
+     FROM (domain_allows
+       LEFT JOIN domain_counts ON (((domain_counts.domain)::text = (domain_allows.domain)::text)));
+  SQL
+  add_index "instances", ["domain"], name: "index_instances_on_domain", unique: true
+
 end
diff --git a/db/views/instances_v01.sql b/db/views/instances_v01.sql
new file mode 100644
index 000000000..94acd61a1
--- /dev/null
+++ b/db/views/instances_v01.sql
@@ -0,0 +1,17 @@
+WITH domain_counts(domain, accounts_count)
+AS (
+  SELECT domain, COUNT(*) as accounts_count
+  FROM accounts
+  WHERE domain IS NOT NULL
+  GROUP BY domain
+)
+SELECT domain, accounts_count
+FROM domain_counts
+UNION
+SELECT domain_blocks.domain, COALESCE(domain_counts.accounts_count, 0)
+FROM domain_blocks
+LEFT OUTER JOIN domain_counts ON domain_counts.domain = domain_blocks.domain
+UNION
+SELECT domain_allows.domain, COALESCE(domain_counts.accounts_count, 0)
+FROM domain_allows
+LEFT OUTER JOIN domain_counts ON domain_counts.domain = domain_allows.domain
diff --git a/lib/mastodon/domains_cli.rb b/lib/mastodon/domains_cli.rb
index 5433ddd9d..3c2dfd4ec 100644
--- a/lib/mastodon/domains_cli.rb
+++ b/lib/mastodon/domains_cli.rb
@@ -53,6 +53,8 @@ module Mastodon
       custom_emojis_count = custom_emojis.count
       custom_emojis.destroy_all unless options[:dry_run]
 
+      Instance.refresh unless options[:dry_run]
+
       say("Removed #{custom_emojis_count} custom emojis", :green)
     end
 
@@ -83,7 +85,7 @@ module Mastodon
       processed       = Concurrent::AtomicFixnum.new(0)
       failed          = Concurrent::AtomicFixnum.new(0)
       start_at        = Time.now.to_f
-      seed            = start ? [start] : Account.remote.domains
+      seed            = start ? [start] : Instance.pluck(:domain)
       blocked_domains = Regexp.new('\\.?' + DomainBlock.where(severity: 1).pluck(:domain).join('|') + '$')
       progress        = create_progress_bar
 
diff --git a/spec/controllers/admin/instances_controller_spec.rb b/spec/controllers/admin/instances_controller_spec.rb
index 412b81443..8c0b309f2 100644
--- a/spec/controllers/admin/instances_controller_spec.rb
+++ b/spec/controllers/admin/instances_controller_spec.rb
@@ -9,10 +9,10 @@ RSpec.describe Admin::InstancesController, type: :controller do
 
   describe 'GET #index' do
     around do |example|
-      default_per_page = Account.default_per_page
-      Account.paginates_per 1
+      default_per_page = Instance.default_per_page
+      Instance.paginates_per 1
       example.run
-      Account.paginates_per default_per_page
+      Instance.paginates_per default_per_page
     end
 
     it 'renders instances' do
diff --git a/spec/models/account_spec.rb b/spec/models/account_spec.rb
index 75f628076..1d000ed4d 100644
--- a/spec/models/account_spec.rb
+++ b/spec/models/account_spec.rb
@@ -440,13 +440,6 @@ RSpec.describe Account, type: :model do
     end
   end
 
-  describe '.domains' do
-    it 'returns domains' do
-      Fabricate(:account, domain: 'domain')
-      expect(Account.remote.domains).to match_array(['domain'])
-    end
-  end
-
   describe '#statuses_count' do
     subject { Fabricate(:account) }
 
@@ -737,20 +730,6 @@ RSpec.describe Account, type: :model do
       end
     end
 
-    describe 'by_domain_accounts' do
-      it 'returns accounts grouped by domain sorted by accounts' do
-        2.times { Fabricate(:account, domain: 'example.com') }
-        Fabricate(:account, domain: 'example2.com')
-
-        results = Account.where('id > 0').by_domain_accounts
-        expect(results.length).to eq 2
-        expect(results.first.domain).to eq 'example.com'
-        expect(results.first.accounts_count).to eq 2
-        expect(results.last.domain).to eq 'example2.com'
-        expect(results.last.accounts_count).to eq 1
-      end
-    end
-
     describe 'local' do
       it 'returns an array of accounts who do not have a domain' do
         account_1 = Fabricate(:account, domain: nil)