[nojvek]

This goes into CAP theorem. Do you want async/inconsistent read replicas or consistent replicas with guaranteed “read new info after write everywhere” semantics.

To get consistent reads, every write needs to wait to ensure every node has acknowledged the write and then return.

So yes, you can have single digit ms sql queries, but you’d pay the price of writes being bottlenecked by speed of all nodes acknowledging the writes.