Amazon SimpleDB

Amazon SimpleDB is a distributed database believed to be written in Erlang by Amazon.com. It is used as a web service in concert with Amazon Elastic Compute Cloud (EC2) and Amazon S3 and is part of Amazon Web Services. It was announced on December 13, 2007.

As with EC2 and S3, Amazon charges fees for SimpleDB storage, transfer, and throughput over the Internet. Transfer to other Amazon Web Services is free of charge.

Nitin Borwankar of GigaOM called SimpleDB "hugely disruptive" [in a positive way] to the database market. It has some similarities to CouchDB.

Limitations of SimpleDB

Maximum size of domains

10GB

Maximum domains

100

Maximum attributes per item

256

Maximum size per attribute

1024 characters

Maximum attributes per domain

250,000,000

Maximum items returned in a query response

250

Maximum seconds a query may run

5

Maximum attribute names per query predicate

1

Maximum operators per predicate

5

Maximum predicates per query

5