```
touch /tmp/aaa.csv

CREATE TABLE log (A String) ENGINE= FileLog('/tmp/aaa.csv', 'CSV');
DB::Exception: The absolute data path should be inside `user_files_path`(/var/lib/clickhouse/user_files/). (BAD_ARGUMENTS)


CREATE TABLE log (A String) ENGINE= FileLog('/tmp/aaa.csv', 'CSV');
DB::Exception: Metadata files already exist by path: /var/lib/clickhouse/.filelog_storage_metadata/default/log, remove them manually if it is intended. (TABLE_METADATA_ALREADY_EXISTS)
```
if (file_infos.file_names.empty())
    {
        LOG_WARNING(log, "There is a idle table named {}, no files need to parse.", getName());
        return Pipe{};
    }
    auto modified_context = Context::createCopy(local_context);
    auto max_streams_number = std::min<UInt64>(filelog_settings->max_threads, file_infos.file_names.size());
    
    openFilesAndSetPos();
    Pipes pipes;
    pipes.reserve(max_streams_number);
    for (size_t stream_number = 0; stream_number < max_streams_number; ++stream_number)
    {
        pipes.emplace_back(std::make_shared<FileLogSource>(
            *this,
            metadata_snapshot,
            modified_context,
            column_names,
            getMaxBlockSize(),
            getPollTimeoutMillisecond(),
            stream_number,
            max_streams_number));
    }
    return Pipe::unitePipes(std::move(pipes));
}
void StorageFileLog::increaseStreams()
{
    running_streams += 1;
}
void StorageFileLog::reduceStreams()