suggestion regarding dbConnect params

[alanpaulkwan]

Looking at the dbConnect, it seems there's basically no way to specify the max_memory_usage and max_bytes_before_external_group_by etc. for dbConnect. Would this be possible to change? I figure it's a good idea to be able to map all clickhouse--client params -- these are fairly important ones.

[inkrement]

Sounds like a good idea! We will take a look at it, but you can also provide a pull request.