I am reading clickhouse mutation code. In StorageMergeTree->selectPartsToMutate() function, there is a check 
`if (current_ast_elements + commands_size >= max_ast_elements)
                break;`

I think if there are many mutations then the check result will be true, so that it will skip the remaining mutations.
But the new part's mutation is set to the last one in mutation map, and it does not apply the remaining mutations actually.
`new_part_info.mutation = current_mutations_by_version.rbegin()->first;`

Then the new part will miss the remaining mutations in future mutation job.

I think it's wrong here. Am I right?

If it is right, I will submit a PR 

}
        bool miss_column = true;
        for (const auto & column : columns)
        {
            if (column.name == sign_column)
            {
                if (!typeid_cast<const DataTypeInt8 *>(column.type.get()))
                    throw Exception("Sign column (" + sign_column + ") for storage " + storage + " must have type Int8."
                            " Provided column of type " + column.type->getName() + ".", ErrorCodes::BAD_TYPE_OF_FIELD);
                miss_column = false;
                break;
            }
        }
        if (miss_column)
            throw Exception("Sign column " + sign_column + " does not exist in table declaration.", ErrorCodes::NO_SUCH_COLUMN_IN_TABLE);
    };
    
    auto check_version_column = [this, & columns](bool is_optional, const std::string & storage)
    {
        if (version_column.empty())
        {
            if (is_optional)
                return;
            throw Exception("Logical error: Version column for storage " + storage + " is empty", ErrorCodes::LOGICAL_ERROR);
        }
        bool miss_column = true;
        for (const auto & column : columns)
        {
            if (column.name == version_column)
            {