1 files changed, 29 insertions, 0 deletions
diff --git a/db/migrate/20210818055357_add_unique_commit_design_user_mention_indexes.rb b/db/migrate/20210818055357_add_unique_commit_design_user_mention_indexes.rb
new file mode 100644
index 00000000000..d9d05f2b737
--- /dev/null
+++ b/db/migrate/20210818055357_add_unique_commit_design_user_mention_indexes.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+class AddUniqueCommitDesignUserMentionIndexes < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  COMMIT_INDEX_NAME = 'commit_id_and_note_id_index'
+  DESIGN_INDEX_NAME = 'design_user_mentions_on_design_id_and_note_id_index'
+
+  COMMIT_UNIQUE_INDEX_NAME = 'commit_user_mentions_on_commit_id_and_note_id_unique_index'
+  DESIGN_UNIQUE_INDEX_NAME = 'design_user_mentions_on_design_id_and_note_id_unique_index'
+
+  def up
+    add_concurrent_index :commit_user_mentions, [:commit_id, :note_id], unique: true, name: COMMIT_UNIQUE_INDEX_NAME
+    add_concurrent_index :design_user_mentions, [:design_id, :note_id], unique: true, name: DESIGN_UNIQUE_INDEX_NAME
+
+    remove_concurrent_index_by_name :commit_user_mentions, COMMIT_INDEX_NAME
+    remove_concurrent_index_by_name :design_user_mentions, DESIGN_INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index :design_user_mentions, [:design_id, :note_id], name: DESIGN_INDEX_NAME
+    add_concurrent_index :commit_user_mentions, [:commit_id, :note_id], name: COMMIT_INDEX_NAME
+
+    remove_concurrent_index_by_name :design_user_mentions, DESIGN_UNIQUE_INDEX_NAME
+    remove_concurrent_index_by_name :commit_user_mentions, COMMIT_UNIQUE_INDEX_NAME
+  end
+end