```
milovidov-desktop :) CREATE TABLE perf_lc_num(　        num UInt8,　        arr Array(LowCardinality(Int64)) default [num]　        ) ENGINE = TinyLog

CREATE TABLE perf_lc_num
(
    `num` UInt8,
    `arr` Array(LowCardinality(Int64)) DEFAULT [num]
)
ENGINE = TinyLog

Query id: e95f9a71-5795-4dea-8d80-4729fc8016b9

Ok.

0 rows in set. Elapsed: 0.002 sec. 

milovidov-desktop :) INSERT INTO perf_lc_num (num)
:-]         SELECT toUInt8(number)
:-]         FROM numbers(100000000)

INSERT INTO perf_lc_num (num) SELECT toUInt8(number)
FROM numbers(100000000)

Query id: 1101fd75-a545-4809-acb5-8afa2fae80c0


Received exception from server (version 20.13.1):
Code: 49. DB::Exception: Received from localhost:9000. DB::Exception: Got empty stream for DataTypeLowCardinality keys.: While executing SinkToOutputStream. 

0 rows in set. Elapsed: 0.045 sec. 

milovidov-desktop :) INSERT INTO perf_lc_num (num)　        SELECT toUInt8(number)　        FROM numbers(100000000)

INSERT INTO perf_lc_num (num) SELECT toUInt8(number)
FROM numbers(100000000)

Query id: 0ad8532a-5c6e-4590-84cd-7e00759d152d


Received exception from server (version 20.13.1):
Code: 49. DB::Exception: Received from localhost:9000. DB::Exception: Got empty stream for DataTypeLowCardinality keys.: While executing SinkToOutputStream. 

0 rows in set. Elapsed: 0.033 sec.
```

{
public:
    static Block getHeader(const NamesAndTypesList & columns)
    {
        Block res;
        for (const auto & name_type : columns)
            res.insert({ name_type.type->createColumn(), name_type.type, name_type.name });
        return Nested::flatten(res);
    }
    TinyLogSource(
        size_t block_size_,
        const NamesAndTypesList & columns_,
        StorageTinyLog & storage_,
        size_t max_read_buffer_size_,
        FileChecker::Map file_sizes_)
        : SourceWithProgress(getHeader(columns_))
        , block_size(block_size_), columns(columns_), storage(storage_)
        , max_read_buffer_size(max_read_buffer_size_), file_sizes(std::move(file_sizes_))
    {
    }
    String getName() const override { return "TinyLog"; }