Goal: Explore Postgres 11’s Declarative Partitioning features This entire post is detailed explanation of a thread in postgresql mailing list and wonderful answers by David Rowley Why do I need partitions? I already have an index! A partition is a logical unit that can be drop-ed and removed from queried dataset as well as the database detach-ed from the frequently queried dataset, but retained in the database for adhoc queries detach-ed and attach-ed somewhere else (say, another table in same postgres instance) Whenever optmizer decides to fall back to a sequential scan, you would be scanning a smaller table.