I have to say, this problem has not been well solved. But we've still been doing something:

- We used gRPC with no compression before, and we tune an acceptable compression level to achieve a balance of performance and data volume.

- Improve our SQL optimizer to consider the network cost more accurately and data placement rule to balance data more logically to reduce data transfer crossing AZ.

- As a cloud service, we will also expose the cost transparently to our customers like MongoDB Atlas does. :-)