```sql
drop table if exists src;

create table src( A Int64, B String, C String) Engine=MergeTree order by A
SETTINGS min_bytes_for_wide_part=0;
insert into src values(1, 'one', 'test');

alter table src detach partition tuple();

alter table src modify column B Nullable(String);

alter table src attach partition tuple();
select * from src;
┌─A─┬─B───┬─C────┐
│ 1 │ one │ test │
└───┴─────┴──────┘

alter table src update C = 'test1' where 1 settings mutations_sync=2;

select * from src;
┌─A─┬─B────┬─C─────┐
│ 1 │ ᴺᵁᴸᴸ │ test1 │   -- expected B='one'
└───┴──────┴───────┘
```

```sql
drop table if exists src;
create table src( A String, B String, C String) Engine=MergeTree order by A
SETTINGS min_bytes_for_wide_part=0;
insert into src values('one', 'one', 'test');

alter table src detach partition tuple();

alter table src modify column A LowCardinality(String);

alter table src attach partition tuple();

select * from src;
┌─A───┬─B───┬─C────┐
│ one │ one │ test │
└─────┴─────┴──────┘

alter table src update C = 'test1' where 1 settings mutations_sync=2;

select * from src;

Received exception from server (version 22.9.1):
Code: 49. DB::Exception: Received from localhost:9000. DB::Exception: 
Got empty stream for SerializationLowCardinality keys.: (while reading column A): 
(while reading from part /var/lib/clickhouse/store/11b/11b74812-48b9-4c1f-9bdc-3e7a28137a9e/all_3_3_0_4/ from mark 0 with max_rows_to_read = 1): 
While executing MergeTreeInOrder. (LOGICAL_ERROR)

```

```sql
drop table if exists src;
create table src( A String, B String, C String) Engine=MergeTree order by A
SETTINGS min_bytes_for_wide_part=0;
insert into src values('one', 'one', 'test');

alter table src detach partition tuple();

alter table src modify column A LowCardinality(String);

alter table src attach partition tuple();

select * from src;
┌─A───┬─B───┬─C────┐
│ one │ one │ test │
└─────┴─────┴──────┘

alter table src modify column C LowCardinality(String);

select * from src;

Received exception from server (version 22.9.3):
Code: 49. DB::Exception: Received from localhost:9000. 
DB::Exception: Got empty stream for SerializationLowCardinality keys.: 
```

related https://github.com/ClickHouse/ClickHouse/issues/42083 , https://github.com/ClickHouse/ClickHouse/issues/42074
(basically it's the same one issue, but I opened this one, because I think the root issue is in `alter update`.

it seems `alter update` updates columns.txt for all columns even if they are not participated in the `alter update`.
{
        auto & current_level_parts = level_parts[current_level];
        auto & next_level_parts = level_parts[next_level];
        MergeTreeData::MutableDataPartsVector selected_parts;
        while (selected_parts.size() < max_parts_to_merge_in_one_level && !current_level_parts.empty())
        {
            selected_parts.push_back(std::move(current_level_parts.back()));
            current_level_parts.pop_back();
        }
        if (selected_parts.empty())
        {
            if (next_level_parts.empty())
            {
                LOG_WARNING(log, "There is no projection parts merged");
                
                return false;
            }
            current_level = next_level;
            ++next_level;
        }
        else if (selected_parts.size() == 1)
        {
            if (next_level_parts.empty())
            {
                LOG_DEBUG(log, "Merged a projection part in level {}", current_level);
                auto builder = selected_parts[0]->data_part_storage->getBuilder();
                selected_parts[0]->renameTo(projection.name + ".proj", true, builder);
                selected_parts[0]->name = projection.name;
                selected_parts[0]->is_temp = false;
                builder->commit();