1 files changed, 41 insertions, 0 deletions
diff --git a/lib/gitlab/database/tables_sorted_by_foreign_keys.rb b/lib/gitlab/database/tables_sorted_by_foreign_keys.rb
new file mode 100644
index 00000000000..9f096904d31
--- /dev/null
+++ b/lib/gitlab/database/tables_sorted_by_foreign_keys.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Database
+    class TablesSortedByForeignKeys
+      include TSort
+
+      def initialize(connection, tables)
+        @connection = connection
+        @tables = tables
+      end
+
+      def execute
+        strongly_connected_components
+      end
+
+      private
+
+      def tsort_each_node(&block)
+        tables_dependencies.each_key(&block)
+      end
+
+      def tsort_each_child(node, &block)
+        tables_dependencies[node].each(&block)
+      end
+
+      # it maps the tables to the tables that depend on it
+      def tables_dependencies
+        @tables.to_h do |table_name|
+          [table_name, all_foreign_keys[table_name]&.map(&:from_table).to_a]
+        end
+      end
+
+      def all_foreign_keys
+        @all_foreign_keys ||= @tables.flat_map do |table_name|
+          @connection.foreign_keys(table_name)
+        end.group_by(&:to_table)
+      end
+    end
+  end
+end