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

3 files changed, 58 insertions, 53 deletions

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
+                •
+              = t('admin.domain_blocks.rejecting_media')
+              - first_item = false
+            - if instance.domain_block.reject_reports?
+              - unless first_item
+                •
+              = 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
-                  •
-                = t('admin.domain_blocks.rejecting_media')
-                - first_item = false
-              - if instance.domain_block.reject_reports?
-                - unless first_item
-                  •
-                = 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'