22.2.1.4422.

```
create table test_alias (K Int64, D Date, S String, B Int64 Alias length(S)) Engine=MergeTree order by K;
insert into test_alias select number, today(), 'sdfsdfsdfsdfsdfds' from numbers(10000000);

session1: 
clickhouse-benchmark -c 10 <<< "insert into test_alias select number, today(), 'sdfsdfsdfsdfsdfds' from numbers(10000)"

session2: 
alter table test_alias drop column B;
0 rows in set. Elapsed: 251.043 sec.
```

especially it can be a problem with S3 disks

Alias columns do not persist in parts even in columns.txt
{
    if (property.empty())
        return AlterCommand::RemoveProperty::NO_PROPERTY;
    else if (property == "DEFAULT")
        return AlterCommand::RemoveProperty::DEFAULT;
    else if (property == "MATERIALIZED")
        return AlterCommand::RemoveProperty::MATERIALIZED;
    else if (property == "ALIAS")
        return AlterCommand::RemoveProperty::ALIAS;
    else if (property == "COMMENT")
        return AlterCommand::RemoveProperty::COMMENT;
    else if (property == "CODEC")
        return AlterCommand::RemoveProperty::CODEC;
    else if (property == "TTL")
        return AlterCommand::RemoveProperty::TTL;
    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Cannot remove unknown property '{}'", property);
}
}
std::optional<AlterCommand> AlterCommand::parse(const ASTAlterCommand * command_ast)