“Big data” features coming in PostgreSQL 9.5
Today, it is still heavily used in mid-sized data warehouses and “data marts”, meaning databases in the one to ten terabyte range.
.. There are some drawbacks to BRIN indexes, though. They can’t be used to enforce uniqueness or support keys. BRIN works much better on values that are incrementally increasing with each row inserted, like timestamps and incrementing integers. Most of all, BRIN indexes handle updates and deletes on the underlying table inefficiently, so they’re best used with append-only tables.