Amazon SimpleDB Functionality

Amazon SimpleDB provides a simple web services interface to create and store multiple data sets, query your data easily, and return the results. Your data is automatically indexed, making it easy to quickly find the information that you need. There is no need to pre-define a schema or change a schema if new data is added later. And scale-out is as simple as creating new domains, rather than building out new servers.

To use Amazon SimpleDB you:

• Build your data set

  • Use CreateDomain, DeleteDomain, ListDomains, DomainMetadata to create and manage query domains
  • Use Put, Batch Put, & Delete to create and manage the data set within each query domain

• Retrieve your data

  • Use GetAttributes to retrieve a specific item
  • Use Select to query your data set for items that meet specified criteria

• Pay only for the resources that you consume

Service Highlights

Simple to use – Amazon SimpleDB provides streamlined access to the store and query functions that traditionally are achieved using a relational database cluster – while leaving out other complex, often-unused database operations. The service allows you to quickly add data and easily retrieve or edit that data through a simple set of API calls.

Low touch – Accessing these capabilities through the AWS cloud eliminates the complexity of maintaining and scaling these operations in-house. The service allows you to focus on value-added application development, rather than arduous and time-consuming database administration.

Scalable – Amazon SimpleDB allows you to easily scale-out your database processing as demand for your application grows. Horizontal scale-out, via the creation of new domains, allows you to easily respond to growth in both data volume and requests.

Highly available – The service runs within Amazon’s high-availability data centers. Data stored in Amazon SimpleDB is geographically dispersed and automatically replicated for high availability and durability.

Fast – Amazon SimpleDB provides quick, efficient storage and retrieval of your data to support high performance web applications. Applications running fully within the Amazon cloud (e.g. a SimpleDB request originating from an application running on Amazon EC2), will provide near-LAN latency.

Flexible – With Amazon SimpleDB, it is not necessary to pre-define all of the data formats you will need to store; simply add new attributes to your Amazon SimpleDB data set when needed, and the system will automatically index your data accordingly. The ability to store structured data without first defining a schema provides developers with greater flexibility when building applications, and eliminates the need to re-factor an entire database as those applications evolve.

Designed for use with other Amazon Web Services – Amazon SimpleDB is designed to integrate easily with other AWS services such as Amazon S3 and EC2, providing the infrastructure for creating web-scale applications. For example, developers can run their applications in Amazon EC2 and store their data objects in Amazon S3. Amazon SimpleDB can then be used to query the object metadata from within the application in Amazon EC2 and return pointers to the objects stored in Amazon S3.

Inexpensive – Amazon SimpleDB passes on to you the financial benefits of Amazon’s scale. You pay only for resources you actually consume. Compare this with the significant up-front expenditures traditionally required to obtain software licenses and purchase and maintain hardware, either in-house or hosted. This frees you from many of the complexities of capacity planning, transforms large capital expenditures into much smaller operating costs, and eliminates the need to over-buy “safety net” capacity to handle periodic traffic spikes.

Pricing

As your demand grows, you still pay only for what you use. As with other AWS services, there is no minimum fee and no long-term commitment.

Machine Utilization

• First 25 Amazon SimpleDB Machine Hours consumed per month are free
• $0.14 per Amazon SimpleDB Machine Hour consumed thereafter

Amazon SimpleDB measures the machine utilization of each request and charges based on the amount of machine capacity used to complete the particular request (SELECT, GET, PUT, etc.), normalized to the hourly capacity of a circa 2007 1.7 GHz Xeon processor.

Data Transfer

• First 1 GB of data transferred in per month is free
• $0.100 per GB – all data transfer in thereafter

• First 1 GB of data transferred out per month is free; thereafter:
• $0.170 per GB – first 10 TB / month data transfer out
• $0.130 per GB – next 40 TB / month data transfer out
• $0.110 per GB – next 100 TB / month data transfer out
• $0.100 per GB – data transfer out / month over 150 TB

Data transfer “in” and “out” refers to transfer into and out of Amazon SimpleDB. Data transferred between Amazon SimpleDB and other Amazon Web Services within the same region is free of charge (i.e., $0.00 per GB). Data transferred across regions (i.e. between Amazon EC2 in the E.U. and SimpleDB), will be charged at Internet Data Transfer rates on both sides of the transfer.

Structured Data Storage

• First 1 GB stored per month is free**
• $0.25 per GB-month thereafter

Amazon SimpleDB measures the size of your billable data by adding the raw byte size of the data you upload + 45 bytes of overhead for each item, attribute name and attribute-value pair.

Amazon SimpleDB is designed to store relatively small amounts of data and is optimized for fast data access and flexibility in how that data is expressed. In order to minimize your costs across AWS services, large objects or files should be stored in Amazon S3, while the pointers and the meta-data associated with those files can be stored in Amazon SimpleDB. This will allow you to quickly search for and access your files, while minimizing overall storage costs. See below for detailed descriptions on calculating your own structured data storage requirements and for a more detailed explanation of how storage in Amazon SimpleDB and storage in Amazon S3 differ.

* The free tier is a monthly offer. Free usage does not accumulate.

** Any data stored as part of the free tier program must be actively used. If a domain is not accessed for a period of 6 months, it will be subject to removal at the discretion of Amazon Web Services.

(Amazon SimpleDB is licensed by Amazon Web Services LLC.)

Resources

Developer Resources

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• WSDL
• Documentation
• Release Notes
• Sample Code & Libraries
• Developer Tools
• Articles & Tutorials
• Community Forum

Additional Product Information

• FAQs
• Amazon Web Services Customer Agreement
• Service Health Dashboard

Related Services

• AWS Premium Support
• Amazon Elastic Compute Cloud
• Amazon Simple Storage Service
• Amazon Simple Queue Service

Detailed Description

The Data Model: Domains, Items, Attributes and Values

The data model used by Amazon SimpleDB makes it easy to input, manage and query your structured data. Developers organize their data-set into domains and can run queries across all of the data stored in a particular domain. Domains are collections of items that are described by attribute-value pairs.

Think of these terms as analogous to concepts in a traditional spreadsheet table. For example, take the details of a customer management database shown in the table below and consider how they would be represented in Amazon SimpleDB. The whole table would be your domain named “customers.” Individual customers would be rows in the table or items in your domain. The contact information would be described by column headers (attributes). Values are in individual cells. Now imagine the records below are new customers you would like to add to your domain.

In Amazon SimpleDB, to add the records above, you would PUT the CustomerIDs into your domain along with the attribute-value pairs for each of the customers. Without the specific syntax, it would look something like this:

PUT (item, 123), (First name, Bob), (Last name, Smith), (Street address, 123 Main St.), (City, Springfield), (State, MO), (Zip, 65801), (Telephone, 222-333-4444) PUT (item, 456), First name, James), (Last name, Johnson), (Street address, 456 Front St.), (City, Seattle), (State, WA), (Zip, 98104), (Telephone, 333-444-5555)

Amazon SimpleDB differs from tables of traditional databases in several important ways. First, you have the flexibility to easily go back later on and add new attributes that only apply to certain records. For example, imagine you begin to capture your customers’ email addresses to enable real-time alerts on order status. Rather than rebuilding your “customer” table, re-writing your queries, rebuilding your indices, and so on, you would simply add the new records and any additional attributes to your existing “customers” domain. The resulting domain might look something like this:

API Summary

Amazon SimpleDB provides a small number of simple API calls which implement writing, indexing and querying data. The interface and feature set are intentionally focused on core functionality, providing a basic API for developers to build upon and making the service easy to learn and simple to use.

• CreateDomain — Create a domain that contains your dataset.
• DeleteDomain — Delete a domain.
• ListDomains — List all domains.
• DomainMetadata — Retrieve information about creation time for the domain, storage information both as counts of item names and attributes, as well as total size in bytes.
• PutAttributes — Add or update an item and its attributes, or add attribute-value pairs to items that exist already. Items are automatically indexed as they are received.
• BatchPutAttributes — For greater overall throughput of bulk writes, perform up to 25 PutAttribute operations in a single call.
• DeleteAttributes — Delete an item, an attribute, or an attribute value.
• GetAttributes — Retrieve an item and all or a subset of its attributes and values.
• Select — Query the data set in the familiar, “select target from domain_name where query_expression” syntax. Supported value tests are: =, !=, <, > <=, >=, like, not like, between, is null, is not null, and every (). Example: select * from mydomain where every(keyword) = ‘Book’. Order results using the SORT operator, and count items that meet the condition(s) specified by the predicate(s) in a query using the Count operator.

Amazon SimpleDB and Relational Databases within AWS

Today, many developers correlate the word “database” with Relational Database Management Systems (RDBMS). While RDBMS offerings provide deep functionality, for many use cases, they introduce more complexity (and more cost) than is 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. Amazon SimpleDB removes the need to maintain a schema, while your attributes are automatically indexed to provide fast real-time lookup and querying capabilities. This flexibility minimizes the performance tuning required as the demands for your data increase.

Amazon SimpleDB eliminates administrative complexity by providing a simple set of APIs focused on the core functionality necessary to store, process, and query your data. The simplicity of this set of APIs, and the ability to access this service “in the cloud,” allow you to quickly develop sophisticated applications without employing a DBA. Amazon SimpleDB allows you to easily scale your application based on your needs. You can quickly create new domains as your data grows or your request throughput increases. You no longer have to be concerned about obtaining software licenses, purchasing and maintain hardware, and managing capacity. You pay only for what you use.

Some developers do require a complex schema or broader functionality, and will undertake the extra work required to run their own relational database. Many developers are doing just this by hosting their own databases inside the Amazon EC2 compute environment. This approach provides flexibility in choosing a database solution, while still offering the benefits of Amazon’s computing infrastructure, including the ability to scale capacity up and down instantly.

Either choice is fine with us. Over time, we plan to continue to add features that make it as easy as possible for developers to pursue whichever option they prefer for obtaining database functionality.

Data Storage in Amazon SimpleDB vs. Data Storage in Amazon S3

Unlike Amazon S3, Amazon SimpleDB is not storing raw data. Rather, it takes your data as input and expands it to create indices across multiple dimensions, which enables you to quickly query that data. Additionally, Amazon S3 and Amazon SimpleDB use different types of physical storage. Amazon S3 uses dense storage drives that are optimized for storing larger objects inexpensively. Amazon SimpleDB stores smaller bits of data and uses less dense drives that are optimized for data access speed.

In order to optimize your costs across AWS services, large objects or files should be stored in Amazon S3, while smaller data elements or file pointers (possibly to Amazon S3 objects) are best saved in Amazon SimpleDB. Because of the close integration between services and the free data transfer within the AWS environment, developers can easily take advantage of both the speed and querying capabilities of Amazon SimpleDB as well as the low cost of storing data in Amazon S3, by integrating both services into their applications.

For the Beta release, a single Amazon SimpleDB domain may grow to 10 GB and you are initially allocated a maximum of 100 domains; however, over time these allocations may be raised. Please complete this form if you require additional domains.

Calculating Your Storage Needs

The best way to predict the size of your structured data storage is as follows:

Raw byte size (GB) of all item IDs + 45 bytes per item + Raw byte size (GB) of all attribute names + 45 bytes per attribute name + Raw byte size (GB) of all attribute-value pairs + 45 bytes per attribute-value pair

To calculate your estimated monthly storage cost, take the resulting size in GB and multiply by $0.25.

Machine Utilization Example

Amazon SimpleDB measures the machine utilization of each request and charges based on the amount of machine capacity used to complete the particular request (SELECT, GET, PUT, etc.), normalized to the hourly capacity of a circa 2007 1.7 GHz Xeon processor. Machine utilization is driven by the amount of data (# of attributes, length of attributes) processed by each request. A GET operation that retrieves 256 attributes will use more resources than a GET that retrieves only 1 attribute. A multi-predicate SELECT that examines 100,000 attributes will cost more than a single predicate query that examines 250.

In the response message for each request, Amazon SimpleDB returns a field called Box Usage. Box Usage is the measure of machine resources consumed by each request. It does not include bandwidth or storage. Box usage is reported as the portion of a machine hour used to complete a particular request. The cost of an individual request is Box Usage (expressed in hours) * $0.14 per Amazon SimpleDB Machine hour. The cost of all your requests is the sum of Box Usage (expressed in hours) * $0.14.

For example, if over the course of a month, the sum of the Box Usage for your requests uses the equivalent of one 1.7 GHz Xeon processor for 9 hours, your charge will be:

9 hours * $0.14 per Amazon SimpleDB Machine hour = $1.26.

Getting Started

The best way to understand Amazon SimpleDB is to work through the Getting Started Guide, part of our Technical Documentation. Within a few minutes, you will be able to create your domain and start building your index!

Intended Usage and Restrictions

Your use of this service is subject to the Amazon Web Services Customer Agreement