I'm not sure I understand precisely what kind of data you are processing and in what way, but it sounds like a PostgreSQL job on a beefy server (lots of RAM) with SSD storage. Postgres is very good at complex queries and concurrent write loads and if you need to scale quickly beyond single server setups, you can probably move your stuff to Amazon Redshift with little effort. Wouldn't recommend "big data" i.e distributed setups at that size yet unless your queries are extremely parallel workloads and you can pay the cost.
In my previous job we processed 100s of millions of row updates daily on a table with much contention and ~200G size and used a single PostgreSQL server with (now somewhat obsoleted by modern PCIe SSDs) TMS RamSAN storage, i.e. Fibre-Channel based Flash. We had some performance bottlenecks due to many indexes, triggers etc. but overall, live query performance was very good.
In my previous job we processed 100s of millions of row updates daily on a table with much contention and ~200G size and used a single PostgreSQL server with (now somewhat obsoleted by modern PCIe SSDs) TMS RamSAN storage, i.e. Fibre-Channel based Flash. We had some performance bottlenecks due to many indexes, triggers etc. but overall, live query performance was very good.