pg_pathman extension had been developed by Postgres Professional several years ago. It provides the most effective way to partition tables in a database, capable of having thousands of partitions per table. Later a similar partitioning functionality had appeared in community PostgreSQL, being easier in administration, but remarkably less effective. Now we are working on the unification of both partitioning engines.
pg_pathman extension(see blog post) has some functionality which exceeds that of built-in PostgreSQL partitioning, e.g. automatic partition creation and lock-free table partitioning in a "concurrently" style.
Now our goal is to merge the advantages of pg_pathman with the convenience of declarative partitioning. The results are intended to be committed to open source PostgreSQL.