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 

{
    if (from->getName() == to->getName())
        return true;
    
    
    
    if (const auto * from_enum8 = typeid_cast<const DataTypeEnum8 *>(from))
    {
        if (const auto * to_enum8 = typeid_cast<const DataTypeEnum8 *>(to))
            return to_enum8->contains(*from_enum8);
        if (typeid_cast<const DataTypeInt8 *>(to))
            return true;    
        return false;
    }
    if (const auto * from_enum16 = typeid_cast<const DataTypeEnum16 *>(from))
    {
        if (const auto * to_enum16 = typeid_cast<const DataTypeEnum16 *>(to))
            return to_enum16->contains(*from_enum16);
        if (typeid_cast<const DataTypeInt16 *>(to))
            return true;    
        return false;
    }
    if (const auto * from_lc = typeid_cast<const DataTypeLowCardinality *>(from))
        return from_lc->getDictionaryType()->equals(*to);
    if (const auto * to_lc = typeid_cast<const DataTypeLowCardinality *>(to))
        return to_lc->getDictionaryType()->equals(*from);
    return false;
}
void checkVersionColumnTypesConversion(const IDataType * old_type, const IDataType * new_type, const String column_name)