Update total storage size when changing size of artifacts

app/models/project_statistics.rb

@@ -5,7 +5,7 @@ class ProjectStatistics < ActiveRecord::Base
   before_save :update_storage_size
 
   COLUMNS_TO_REFRESH = [:repository_size, :lfs_objects_size, :commit_count].freeze
-  INCREMENTABLE_COLUMNS = [:build_artifacts_size].freeze
+  INCREMENTABLE_COLUMNS = { build_artifacts_size: %i[storage_size] }.freeze
 
   def total_repository_size
     repository_size + lfs_objects_size
@@ -38,11 +38,28 @@ class ProjectStatistics < ActiveRecord::Base
     self.storage_size = repository_size + lfs_objects_size + build_artifacts_size
   end
 
+  # Since this incremental update method does not call update_storage_size above,
+  # we have to update the storage_size here as additional column.
+  # Additional columns are updated depending on key => [columns], which allows
+  # to update statistics which are and also those which aren't included in storage_size
+  # or any other additional summary column in the future.
   def self.increment_statistic(project_id, key, amount)
-    raise ArgumentError, "Cannot increment attribute: #{key}" unless key.in?(INCREMENTABLE_COLUMNS)
+    raise ArgumentError, "Cannot increment attribute: #{key}" unless INCREMENTABLE_COLUMNS.key?(key)
     return if amount == 0
 
     where(project_id: project_id)
-      .update_all(["#{key} = COALESCE(#{key}, 0) + (?)", amount])
+      .columns_to_increment(key, amount)
+  end
+
+  def self.columns_to_increment(key, amount)
+    updates = ["#{key} = COALESCE(#{key}, 0) + (#{amount})"]
+
+    if (additional = INCREMENTABLE_COLUMNS[key])
+      additional.each do |column|
+        updates << "#{column} = COALESCE(#{column}, 0) + (#{amount})"
+      end
+    end
+
+    update_all(updates.join(', '))
   end
 end

changelogs/unreleased/fix-storage-size-for-artifacts-change.yml

+---
+title: Update total storage size when changing size of artifacts
+merge_request: 20697
+author: Peter Marko
+type: fixed

spec/models/project_statistics_spec.rb

@@ -128,6 +128,12 @@ describe ProjectStatistics do
         .by(13)
     end
 
+    it 'increases also storage size by that amount' do
+      expect { described_class.increment_statistic(project.id, :build_artifacts_size, 20) }
+        .to change { statistics.reload.storage_size }
+        .by(20)
+    end
+
     context 'when the amount is 0' do
       it 'does not execute a query' do
         project