PostgreSQL 10: Partitions of partitions

No primary/unique keys on the partition table and only on the partitions still seems like a common dealbreaker.

Is anyone that was using pg_partman before migrated to native partitioning yet? No support for ON CONFLICT and PKs are serious limitations that are available with pg_partman.

Can anyone offer a really basic summary of what problems can be solved with PostgreSQL partitions?

How is this better than inherited tables with indexes and constraints ala <a href="https:&#x2F;&#x2F;stackoverflow.com&#x2F;a&#x2F;3075248" rel="nofollow">https:&#x2F;&#x2F;stackoverflow.com&#x2F;a&#x2F;3075248</a>