I'm guessing he means a "Real-time Operational Database". This seems to be a generic term for system like a data warehouse that contains current data, instead of just historical data. If you are taking the output of a Spark flow and storing it in Postgres or MongoDB or HBase for applications to query, then those could be considered RODBs.

Since this is Amazon, I suspect he is referring to SPICE (or their internal version), which was released last fall as part of AWS's QuickSight BI offering...

"SPICE: One of the key ingredients that make QuickSight so powerful is the Super-fast, Parallel, In-memory Calculation Engine (SPICE). SPICE is a new technology built from the ground up by the same team that has also built technologies such as DynamoDB, Amazon Redshift, and Amazon Aurora. SPICE enables QuickSight to scale to many terabytes of analytical data and deliver response time for most visualization queries in milliseconds. When you point QuickSight to a data source, data is automatically ingested into SPICE for optimal analytical query performance. SPICE uses a combination of columnar storage, in-memory technologies enabled through the latest hardware innovations, machine code generation, and data compression to allow users to run interactive queries on large datasets and get rapid responses."

http://www.allthingsdistributed.com/2015/10/amazon-quicksigh...

Read-only DB. Think of it as read-only memory mapped key/value store.

Good question. Is it this [0]?

[0] http://researcher.watson.ibm.com/researcher/view_group.php?i...

Like rocksdb or lmdb but optimized for reads. Read-only DB.