DynamoDB

DynamoDB

What is Amazon DynamoDB? - Amazon DynamoDBAmazon DynamoDB

• AWS's Serverless, NoSQL fully managed database.

  • Provides zero downtime maintenance and it has no versions (major, minor, or patch).

  • As NoSQL it does not support JOIN operations.

  • It is recommended to denormalize your data models to reduce round trips and processing power to queries.

  • But it still provides read consistency and ACID transactions.

• It's purpose for operational workloads that require consistent performance at any scale.

  • Ex.: It delivers single-digit milisecond performance for a shopping cart use case, whether you have 10 or 100 million users.

• Uses IAM to help you securely control access to your DynamoDB resources.

  • Because of this, there are no usernames or passwords for accessing it.

• By default DynamoDB encrypts all custumer data at rest.

• By default, DynamoDB automatically replicates your data across three AZs.

• Continuous backups provide you per-second granularity to recovery.

  • You can restore a table to any point in time up to the second during the last 35 days.

  • And these backups and restores don't use provisioned capacity.

  • And put no impact on the performance or availability of your applications.

Global Tables

DynamoDB global tables enable a 99.999% availability and multi-Region resilience.

Capacity Modes

Provisioned

• You specify the number of reads and writes per second that you expect your application to require.

• You can use autoscaling can adjust provisioned capacity based on demand.

• Use cases:

  • Predictable traffic.

  • Traffic is consistent or ramps gradually.

On-Demand

• Pay-as-you-go pricing for read and write requests.

• Instantly scales up or down your tables to adjust for capacity. (Zero capacity planning)

• Also scales down to zero so you don't pay for throughput when your table doesn't have traffic.

• No cold starts.

• Use cases:

  • Unpredictable traffic.

  • Traffic hard to forecast.

Usual Table Example

• Tables: ex.: Person.

• Attributes: ex.: FirstName, LastName, Email, ...

• Items: ex.: Persons table contains items of individual people.

• Partition Keys and optional Sort Key defined for fast access to items.

Basic Price Models

• DynamoDB charges for reading, writing and storing data in your tables, along with any optional features you choose to enable.

• Price also depends on the capacity mode:

  • on-demand: Pay only for what you use.

  • provisioned: You will be charged for the throughput capacity event if not fully utilized.

• It offers a free tier that provides 25GB of storage, and can handle 200 Million requests per month.