**Describe the situation**

```
SELECT * FROM test.hits INTO OUTFILE 'dump.csv' FORMAT CSV

8873898 rows in set. Elapsed: 32.487 sec. Processed 8.87 million rows, 8.46 GB (273.15 thousand rows/s., 260.42 MB/s.)
```

is bounded by single CPU core. Too slow :(
initBlockOutputStream(block, parsed_query
    output_format->setTotals(block
}
void ClientBase::onExtremes(Block & block, ASTPtr parsed_query)
{
    initBlockOutputStream(block, parsed_query
    output_format->setExtremes(block
}
void ClientBase::onReceiveExceptionFromServer(std::unique_ptr<Exception> && e)
{
    have_error = true;
    server_exception = std::move(e
    resetOutput(
}
void ClientBase::onProfileInfo(const ProfileInfo & profile_info)
{
    if (profile_info.hasAppliedLimit() && output_format)
        output_format->setRowsBeforeLimit(profile_info.getRowsBeforeLimit()
}
void ClientBase::initBlockOutputStream(const Block & block, ASTPtr parsed_query)
{
    if (!output_format)
    {
        /// Ignore all results when fuzzing as they can be huge.
        if (query_fuzzer_runs)
        {
            output_format = std::make_shared<NullOutputFormat>(block
            return;
        }
        WriteBuffer * out_buf = nullptr;