```
ubuntu@ip-172-31-79-147:/opt/downloads$ clickhouse-local --max_threads 8 --query "WITH parseDateTimeBestEffort(extract(_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, (values[3])::UInt64 AS hits FROM file('pageviews*.gz', LineAsString) WHERE length(values) >= 3" | pv > /dev/null
^C01GiB 0:01:08 [ 129MiB/s] [                                                                                                                                                                   <=>                                                                                    ]

ubuntu@ip-172-31-79-147:/opt/downloads$ clickhouse-local --max_threads 8 --query "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, (values[3])::UInt64 AS hits FROM file('pageviews*.gz', LineAsString) WHERE length(values) >= 3" | pv > /dev/null
^C46GiB 0:00:48 [ 175MiB/s] [                                                                                                                                                                                                                                        <=>               ]
```

{
}
String StorageS3Source::KeysIterator::next()
{
    return pimpl->next();
}
Block StorageS3Source::getHeader(Block sample_block, bool with_path_column, bool with_file_column)
{
    if (with_path_column)
        sample_block.insert({DataTypeString().createColumn(), std::make_shared<DataTypeString>(), "_path"});
    if (with_file_column)
        sample_block.insert({DataTypeString().createColumn(), std::make_shared<DataTypeString>(), "_file"});
    return sample_block;
}
StorageS3Source::StorageS3Source(
    bool need_path,
    bool need_file,
    const String & format_,
    String name_,
    const Block & sample_block_,
    ContextPtr context_,
    std::optional<FormatSettings> format_settings_,
    const ColumnsDescription & columns_,
    UInt64 max_block_size_,