```
$ echo '20210101,A' | clickhouse-local --input-format CSV --structure 'd Date, s String' --query "SELECT * FROM table"
Code: 27. DB::Exception: Cannot parse input: expected ',' before: '20210101,A\n': 
Row 1:
Column 0,   name: d, type: Date,   ERROR: text "20210101,A" is not like Date

: While executing ParallelParsingBlockInputFormat: While executing File. (CANNOT_PARSE_INPUT_ASSERTION_FAILED)
```

**How to solve**

Disambiguate while parsing by absense of separators between YYYY-MM-DD.
{
    assert(current >= in.position());
    assert(current <= in.buffer().end());
    const size_t old_bytes = memory.size();
    const size_t additional_bytes = current - in.position();
    const size_t new_bytes = old_bytes + additional_bytes;
    
    
    if (new_bytes == 0)
        return;
    assert(in.position() + additional_bytes <= in.buffer().end());
    memory.resize(new_bytes);
    memcpy(memory.data() + old_bytes, in.position(), additional_bytes);
    in.position() = current;
}
bool loadAtPosition(ReadBuffer & in, Memory<> & memory, char * & current)