Starting with version 12.10.xC4, you can resolve in-place alter operations by running the admin( ) or task( ) SQL administration command with the table update_ipa or fragment update_ipa argument. You can include the parallel option to run the operation in parallel. For example, the following statement removes in-place alter operations in parallel from a table that is named auto:
EXECUTE FUNCTION task('table update_ipa parallel','auto');
See the table and fragment arguments: Compress and optimize storage topic for details.