1 files changed, 31 insertions, 0 deletions
diff --git a/db/migrate/20210107105306_add_diff_type_to_merge_request_diffs.rb b/db/migrate/20210107105306_add_diff_type_to_merge_request_diffs.rb
new file mode 100644
index 00000000000..0b9b5e93054
--- /dev/null
+++ b/db/migrate/20210107105306_add_diff_type_to_merge_request_diffs.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class AddDiffTypeToMergeRequestDiffs < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  UNIQUE_INDEX_NAME = 'index_merge_request_diffs_on_unique_merge_request_id'
+
+  def up
+    unless column_exists?(:merge_request_diffs, :diff_type)
+      with_lock_retries do
+        add_column :merge_request_diffs, :diff_type, :integer, null: false, limit: 2, default: 1
+      end
+    end
+
+    add_concurrent_index :merge_request_diffs, :merge_request_id, unique: true, where: 'diff_type = 2', name: UNIQUE_INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name(:merge_request_diffs, UNIQUE_INDEX_NAME)
+
+    if column_exists?(:merge_request_diffs, :diff_type)
+      with_lock_retries do
+        remove_column :merge_request_diffs, :diff_type
+      end
+    end
+  end
+end