searching about asynchronous /non-obstructing fittings for mysql i went essentially to this post

However, it has been 24 months and following what is happening on drizzle is a little confusing right now. libdrizzle would be a separate dependency sooner or later however they made the decision to merge it using the relaxation from the project. Exist other available choices for asynchronous database access from c++?

I have been searching at OTL, ODB and OpenDBX, however they all appear to become synchronous (need a separate thread for non-obstructing operation)

I'd exactly the same desire and found the final outcome it's not supported. Despite the MySQL C API you should use the reduced-level functions to problem queries and wait for response asynchronously, however, you cannot find yourself getting full asynchronous result collection--you usually finish up obstructing from the moment the very first bit of it makes sense came back before the last.

I do not have direct knowledge about it, but I have read that Postgres does support full asynchrony (a minimum of within the C API).