1 files changed, 28 insertions, 0 deletions
diff --git a/db/post_migrate/20231016001000_fix_design_user_mentions_design_id_note_id_index_for_self_managed.rb b/db/post_migrate/20231016001000_fix_design_user_mentions_design_id_note_id_index_for_self_managed.rb
new file mode 100644
index 00000000000..454158ecbee
--- /dev/null
+++ b/db/post_migrate/20231016001000_fix_design_user_mentions_design_id_note_id_index_for_self_managed.rb
@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+class FixDesignUserMentionsDesignIdNoteIdIndexForSelfManaged < Gitlab::Database::Migration[2.1]
+  include Gitlab::Database::MigrationHelpers::ConvertToBigint
+
+  disable_ddl_transaction!
+
+  TABLE_NAME = 'design_user_mentions'
+  INDEX_NAME = 'design_user_mentions_on_design_id_and_note_id_unique_index'
+
+  def up
+    return if com_or_dev_or_test_but_not_jh?
+    return if index_exists?(TABLE_NAME, [:design_id, :note_id], unique: true, name: INDEX_NAME)
+
+    add_concurrent_index TABLE_NAME, [:design_id, :note_id], unique: true, name: "#{INDEX_NAME}_int8"
+
+    with_lock_retries(raise_on_exhaustion: true) do
+      execute "LOCK TABLE #{TABLE_NAME} IN ACCESS EXCLUSIVE MODE"
+
+      execute "DROP INDEX IF EXISTS #{INDEX_NAME}"
+      rename_index TABLE_NAME, "#{INDEX_NAME}_int8", INDEX_NAME
+    end
+  end
+
+  def down
+    # no-op
+  end
+end