Amazon on Thursday plans to announce Amazon SimpleDB, a new Web service for querying structured data.

Adam Selipsky, VP of Product Management and Developer Relations, said that Amazon plans post details on the about SimpleDB on its Web site in advance of a limited beta release. The database service will be made available to a limited number of beta testers in the next few weeks. Those wishing to try it will be able to provide an e-mail address to Amazon, which will select and notify beta testers on a first-come, first-serve basis.

Launched in 2002, Amazon Web Services represents a major bet that Amazon can sell access to its IT infrastructure as a utility. In an InformationWeek interview last year, Amazon CEO Jeff Bezos described AWS thus: "What we're doing is leveling the playing field so that small companies can have access to the same low-cost structure as big companies for very reliable backend infrastructure, and to do that in a pay-by-the-drink way -- so that you don't have these big fixed-cost steps that you have to subject yourself to."

There are currently more than 290,000 AWS developers, according to an Amazon spokesperson. At the Web 2.0 Expo 2007 in April, Bezos said that while Amazon intended to make money selling on-demand computing services, AWS was not yet profitable.

SimpleDB is designed to complement two other offerings from Amazon Web Services, Amazon Simple Storage Service (S3), and Amazon Elastic Compute Cloud (EC2).

While S3 is designed to store large objects or files, SimpleDB is optimized for storing smaller bits of data and accessing that data swiftly. "SimpleDB is great for indexing data, for being able to query that data very quickly and efficiently and to be able to return the result," said Selipsky.

Thus specialized search companies are using the service for their document indices.

"It's basically a great place to store metadata and information about objects," said Selipsky. "And often those objects are going to be stored in S3. In addition to being a standalone service, it's really designed to be tightly integrated with our other services."

Selipsky said that SimpleDB was designed to provide an online alternative to traditional relational databases. While the service is not intended for sophisticated database operations like complex joins or advanced mathematical operations, it will be broadly useful for many applications, he said. "Any kind of product catalog will be a popular use case," he said.

Amazon's own Alexa Web information service relies on SimpleDB. Some of the companies using Amazon Web Services include G.ho.st, ElephantDrive, Powerset, and SmugMug.

The SimpleDB documentation notes that traditional relational databases tend to be more complex and costly than necessary.

"Many developers simply want to store, process, and query their data without worrying about managing schemas, maintaining indexes, tuning performance or scaling access to their data," the documentation explains. "Amazon SimpleDB removes the need to maintain a schema, while your attributes are automatically indexed to provide fast real-time lookup and querying capabilities."

SimpleDB costs 14 cents per machine hour, with no minimum fee. This is normalized to the hourly capacity of a 2007 1.7 GHz Xeon processor. There's also a data transfer charge of 10 cents per Gbyte transferred in. For data transferred out, the rate starts at 18 cents per Gbyte for first 10 Tbytes per month, then drops to 16 cents for the next 40 Tbytes per month, and finally drops to 13 cents per Gbyte for 50 Tbytes and beyond per month. These fees apply to data transferred in and out of Amazon SimpleDB. Data transferred between SimpleDB and other Amazon Web services is moved without additional cost. There's also a $1.50 fee per Gbyte per month for the storage of structured data.

There's one significant cost that SimpleDB users can avoid: keeping a database administrator on the payroll.