Amazon DynamoDB On-Demand – No Capacity Planning and Pay-Per-Request Pricing

Just a few years ago, creating a database that could support your business at any scale while providing consistent low latency was a daunting task. That changed for me in 2012 while reading Werner Vogels’ blog post announcing Amazon DynamoDB (it was a few months before I joined AWS). DynamoDB was built on the principles in the original Dynamo paper that Amazon published in 2007. Over the years, lots of new features have been introduced to further simplify how AWS customers use databases. You can now create fully managed, multi-region, multi-master database tables with features such as encryption at rest, point-in-time recovery, in-memory caching, and a 99.99% uptime service level agreement (SLA).

Amazon DynamoDB on-demand

Today we are introducing Amazon DynamoDB on-demand, a flexible new billing option for DynamoDB capable of serving thousands of requests per second without capacity planning. DynamoDB on-demand offers simple pay-per-request pricing for read and write requests so that you only pay for what you use, making it easy to balance costs and performance. For tables using on-demand mode, DynamoDB instantly accommodates customers’ workloads as they ramp up or down to any previously observed traffic level. If the level of traffic hits a new peak, DynamoDB adapts rapidly to accommodate the workload.

In the DynamoDB console, you can choose the on-demand read/write capacity mode when creating a new table, or change it later in the Capacity tab.

Tables using on-demand mode support all DynamoDB features (such as encryption at rest, point-in-time recovery, global tables, and so on) with the exception of auto scaling, which is not applicable with this mode.

Indexes created on a table using on-demand mode inherit the same scalability and billing model. You don’t need to specify throughput capacity settings for indexes, and you pay by their use. If you don’t have read/write traffic to a table using on-demand mode and its indexes, you only pay for the data storage.

DynamoDB on-demand is useful if your application traffic is difficult to predict and control, your workload has large spikes of short duration, or if your average table utilization is well below the peak. For example:

• New applications, or applications whose database workload is complex to forecast
• Developers working on serverless stacks with pay-per-use pricing
• SaaS provider and independent software vendors (ISVs) who want the simplicity and resource isolation of deploying a table per subscriber

You can change a table from provisioned capacity to on-demand once per day. You can go from on-demand capacity to provisioned as often as you want.

A quick performance test

Let’s test some load on a newly created DynamoDB table using on-demand mode!

I created two serverless applications:

• The first application creates a REST API on top of a DynamoDB table using an AWS Lambda function and Amazon API Gateway. Using this API, you can read, add, update, and delete items in the table using HTTP methods such as get, post, put, delete.
• The second application starts 1,000 Lambda functions in parallel to generate load on the API endpoint, using random HTTP methods and random data for the items.

Each load generating function runs 100 concurrent requests, and when they are all terminated starts another 100, and so on, for one minute. There is no ramp-up period. Load generation starts immediately at full speed!

As you can see in the metrics tab for this table in the DynamoDB console, I reached a peak of almost 5,000 requests per second very quickly and without any throttling.

The scaling of the serverless stack, from API Gateway to the Lambda function and the DynamoDB table, was fully managed. I didn’t have to plan for the right throughput, and I could focus on the application logic I was building.

With DynamoDB on-demand you pay only for what you use. For example, in the US East (N. Virginia) region, you are charged $1.25 per million write requests units and $0.25 per million read request units, plus the usual data storage costs.

You can use the AWS Command Line Interface (AWS CLI), AWS SDKs, and AWS CloudFormation to create a table using on-demand mode or to change the read/write capacity mode of an existing table.

Available now

The DynamoDB on-demand is available globally in all commercial regions.

You can learn more on the read/write capacity modes in the DynamoDB developer guide.

I am really excited by the new possibilities for developers, ISVs and SaaS providers, and I look forward to seeing what you build with pay-per-request billing.