https://clickhouse-test-reports.s3.yandex.net/17375/99073c26ee2692f8efe2ab14b2d8ae0fd813b80e/fuzzer/fuzzer.log

```
SELECT
    k,
    topK(v)
FROM 
(
    SELECT
        number % 7 AS k,
        arrayMap(x -> arrayMap(x -> if(x = 0, NULL, toString(x)), range(x)), range(intDiv(number, 1))) AS v
    FROM system.numbers
    LIMIT 257
)
GROUP BY k
ORDER BY k ASC
```
{
            if (!is_initialized || is_eof)
                throw DB::Exception("No available data", DB::ErrorCodes::NO_AVAILABLE_DATA);
            return cell.getValue();
        }
    private:
        DB::ReadBuffer & in;
        Cell cell;
        size_t read_count = 0;
        size_t size = 0;
        bool is_eof = false;
        bool is_initialized = false;
    };
    class iterator : public iterator_base<iterator, false>