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 

{
            throw Exception(
                "ALTER ADD INDEX is not supported for tables with the old syntax",
                ErrorCodes::BAD_ARGUMENTS);
        }
        if (command.type == AlterCommand::ADD_PROJECTION && !is_custom_partitioned)
        {
            throw Exception(
                "ALTER ADD PROJECTION is not supported for tables with the old syntax",
                ErrorCodes::BAD_ARGUMENTS);
        }
        if (command.type == AlterCommand::RENAME_COLUMN)
        {
            if (columns_in_keys.count(command.column_name))
            {
                throw Exception(
                    "Trying to ALTER RENAME key " + backQuoteIfNeed(command.column_name) + " column which is a part of key expression",
                    ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN);
            }
        }
        else if (command.type == AlterCommand::DROP_COLUMN)
        {
            if (columns_in_keys.count(command.column_name))
            {
                throw Exception(
                    "Trying to ALTER DROP key " + backQuoteIfNeed(command.column_name) + " column which is a part of key expression",
                    ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN);
            }
            if (!command.clear)
            {