**Describe the situation**
https://markify.dev/p/zfrQMV2/text

**How to reproduce**
On aws `c5ad.24xlarge` run a query:

```
SET max_memory_usage = '100G', max_threads = 1000, max_insert_threads = 96

INSERT INTO wikistat WITH
    parseDateTimeBestEffort(extract(toLowCardinality(_path), 'pageviews-([\\d\\-]+)\\.gz$')) AS time,
    splitByChar(' ', line) AS values,
    splitByChar('.', values[1]) AS projects
SELECT
    time,
    projects[1] AS project,
    projects[2] AS subproject,
    values[2] AS path,
    CAST(values[3], 'UInt64') AS hits
FROM s3('https://....s3.eu-central-1.amazonaws.com/wikistat/original/*.gz', '...', '...', LineAsString, auto)
WHERE length(values) >= 3
```

Performance is not bad (22 million rows are inserted per second) but can be better.
{
    static constexpr bool throw_exception = std::is_same_v<ReturnType, void>;
    auto error = []
    {
        if constexpr (throw_exception)
            throw Exception("Cannot parse date: value is too short", ErrorCodes::CANNOT_PARSE_DATE);
        return ReturnType(false);
    };
    auto append_digit = [&](auto & x)
    {
        if (!buf.eof() && isNumericASCII(*buf.position()))
        {
            x = x * 10 + (*buf.position() - '0');
            ++buf.position();
            return true;
        }
        else
            return false;
    };
    UInt16 year = 0;
    UInt8 month = 0;
    UInt8 day = 0;
    if (!append_digit(year)
        || !append_digit(year) 
        || !append_digit(year) 
        || !append_digit(year)) 
        return error();
    if (buf.eof())
        return error();