Shortly after Google announced Bigtable, Amazon followed with the announcement of its internal Dynamo database at the 21st ACM Symposium on Operating Systems Principles held in October, 2007 (http://www.sosp2007.org).

In the paper, now available on Werner Vogels' site at http://www.allthingsdistributed.com/files/amazon-dynamo-sosp2007.pdf, Amazon described a key-value store called Dynamo that was used to power some of Amazon's most critical internal services such as S3 on AWS. The paper brought to bear some key concepts such as key-value storage, consistent hashing, and vector clocks, among others, that were implemented in Dynamo.

Thus, Dynamo offered an alternative to Bigtable's columnar storage for large-scale datasets by introducing a fundamentally different method that leveraged key-value associations.

In the next few sections, we will discuss the various types of NoSQL technologies and how each of them has characteristics that make them optimal for certain use cases. NoSQL has ushered in a paradigm shift in how we treat databases, and has provided a much-needed alternative view to data management at a scale that was not feasible previously.