Read multiple rows faster than iter method

[Hardik Madhu]

Hi All,

Total Go noob here!!!

Context: We have python app already running on production, but trying to migrate to Go for improved performance and better scalability.

We always need to read upwards of 20 rows at a time, max 60, median is in 30 to 40 range. Python Datastax cassandra drivers' documentation provides a pretty good mechanism for doing these queries - link. With execute async, and callback, we're able query the data with very little additional penalty. i.e. if the Cassandra server took ~40ms to respond, we would have the data in ~50ms. 

I'm trying to do the same queries in go with the iter() method and I see latency in the range of 80-110ms. My go implementation is based on the pagination example. This difference is a quite huge for us, every millisecond counts!! I wonder if this is because of the iterative - fetchOne - nature of the code.

Tried many different things, but I didn't find anything close to execute_async() / fetchall() on a low level yet. Closest I found is "BindMap" on scylla/gosqlx, but it requires quite a lot of setup, and I'm not sure it'll be helpful at the end. Being a complete go newbie i'm not sure what to even "search" for. I would also be more than happy to implement something low level using go routines, but not sure how to go about that either. 

Thanks in advanced!

Best,

Hardik