Big data databases store petabytes of unstructured, semi-structured and structured data without rigid schemas. They are mostly NoSQL (non-relational) databases built on a horizontal architecture, which enable quick and cost-effective processing of large volumes of big data as well as multiple concurrent queries.

Even though non-relational databases have proved to be better for high-performance and agile processing of data at scale, such solutions as Amazon Redshift and Azure Synapse Analytics are now optimized for querying massive data sets, which makes them sufficient when dealing with big data.