Amazon DynamoDB vs Amazon SimpleDB: What are the differences?

Introduction

Amazon DynamoDB and Amazon SimpleDB are both NoSQL databases offered by Amazon Web Services (AWS). While they are both designed to handle large volumes of data, there are key differences between these two services that make them suitable for different use cases. This article outlines the main differences between Amazon DynamoDB and Amazon SimpleDB.

1. Scalability and Performance: One of the main differences between Amazon DynamoDB and Amazon SimpleDB is their scalability and performance capabilities. DynamoDB is designed to handle massive workloads and can scale horizontally across multiple servers to handle high read and write request rates. It also provides predictable performance with low latency, making it suitable for applications that require high throughput. On the other hand, SimpleDB is designed for smaller, less demanding workloads and does not scale as easily as DynamoDB.

2. Data Model: Another major difference between DynamoDB and SimpleDB is their data model. DynamoDB is a key-value store, where each item in the database is uniquely identified by a primary key. It supports both single-item retrieval and batch retrieval, and also provides secondary indexes for flexible querying. SimpleDB, on the other hand, is a schemaless database that uses attributes to store data. Each item can have multiple attributes, and you can perform queries using the attributes as conditions.

3. Consistency Model: Amazon DynamoDB and Amazon SimpleDB have different consistency models. DynamoDB offers both eventually consistent reads and strongly consistent reads. Eventually consistent reads are faster but may not always reflect the latest write operations. Strongly consistent reads ensure that you get the latest data, but may have higher latency. SimpleDB, on the other hand, only supports eventual consistency, so there may be a slight delay in getting the most up-to-date data.

4. Size Limitations: While DynamoDB can handle large datasets, it has certain limitations on the size of individual items and the total amount of data you can store. Each item in DynamoDB can be up to 400 KB in size, and the maximum total size of all items in a table is 10 GB. In comparison, SimpleDB has a more restrictive limit of 1.1 MB for each item.

5. Cost: The pricing structure for DynamoDB and SimpleDB also differs. DynamoDB charges for provisioned throughput, storage, and additional features like global tables. SimpleDB, on the other hand, charges based on the amount of data stored and the number of requests made. For smaller workloads, SimpleDB may be more cost-effective, while DynamoDB is better suited for high-scale applications where performance and scalability are critical.

6. Query Capabilities: DynamoDB and SimpleDB have different query capabilities. DynamoDB supports rich query operations, including both primary key and secondary index queries, as well as conditional queries. It also provides a flexible Query API that allows you to specify filtering conditions. SimpleDB, on the other hand, has a simpler query model that supports basic querying using attributes as conditions.

In summary, Amazon DynamoDB is a highly scalable, performance-oriented NoSQL database that is suitable for large workloads and high throughput applications. It offers strong consistency, rich querying capabilities, and provides flexibility in data modeling. Amazon SimpleDB, on the other hand, is a more lightweight and cost-effective solution that is suitable for smaller workloads and simpler querying needs. It has limitations on scalability and performance, but offers eventual consistency and a simpler data model.