[rkarthik007]

Hi @manigandham, great question. As it stands now, YugaByte would not be a PG extension. It will be a fully distributed but standalone PG cluster called "YSQL" API layer. We have started with the 10.4 version of PG for building distributed YSQL.

PG is planning the pluggable storage API for version 12.0, but these will only address user tables. This is certainly essential, but not sufficient for true distributed SQL. Some of the other pieces are: * Pluggable storage for system tables * Ability to create the initial set of system tables in a pluggable manner (initdb equivalent) * A number of other changes to the upper half of PG in order to make it "stateless" and scale-out, such as modifications to how certain operations are executed, which locks are held, what operations are pushed down to the underlying storage layer, etc. * Support for different types of indexes * Enhancing the optimizer to understand different storage types (in this case a distributed store)

In our current implementation, we have tried to make APIs for the above where ever possible. We need to explore how we can make runtime hooks for the other places. The plan is to see how to contribute these to the open source over the longer time frame so that we can create a self contained extension (though we are nowhere close to that today). Since our PG modifications code-base is open-sourced, the hope is that it would make contributing these changes back to PG easier.