If they are defined, they can override table-level settings.
{
    MutationCommands commands = getFirstAlterMutationCommandsForPart(part);
    AlterConversions result{};
    for (const auto & command : commands)
        /
        /
        /
        if (command.type == MutationCommand::Type::RENAME_COLUMN)
            result.rename_map[command.rename_to] = command.column_name;
    return result;
}
MergeTreeData::WriteAheadLogPtr MergeTreeData::getWriteAheadLog()