```
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] [                                                                                                                                                                                                                                        <=>               ]
```

{
    for (const auto & file : file_infos.file_names)
    {
        auto & file_ctx = findInMap(file_infos.context_by_name, file);
        if (file_ctx.status != FileStatus::NO_CHANGE)
        {
            file_ctx.reader.emplace(getFullDataPath(file));
            auto & reader = file_ctx.reader.value();
            assertStreamGood(reader);
            reader.seekg(0, reader.end);
            assertStreamGood(reader);
            auto file_end = reader.tellg();
            assertStreamGood(reader);
            auto & meta = findInMap(file_infos.meta_by_inode, file_ctx.inode);
            if (meta.last_writen_position > static_cast<UInt64>(file_end))
            {
                throw Exception(
                    ErrorCodes::CANNOT_READ_ALL_DATA,
                    "Last saved offsset for File {} is bigger than file size ({} > {})",
                    file,
                    meta.last_writen_position,
                    file_end);
            }
            
            meta.last_open_end = file_end;
            reader.seekg(meta.last_writen_position);
            assertStreamGood(reader);
        }
    }