How to Fetch the Latest 10 Records in DynamoDB Without Using Scan

Discover efficient techniques for retrieving the latest entries from DynamoDB using Global Secondary Indexes (GSI) without resorting to scans.
---
This video is based on the question https://stackoverflow.com/q/73149447/ asked by the user 'tan' ( https://stackoverflow.com/u/6423160/ ) and on the answer https://stackoverflow.com/a/73149585/ provided by the user 'hunterhacker' ( https://stackoverflow.com/u/538697/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Fetching top 10 records without using scan in DynamoDB

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Fetch the Latest 10 Records in DynamoDB Without Using Scan

When working with large datasets in DynamoDB, efficiently retrieving records is crucial for optimal performance. One common scenario is needing to fetch the latest products based on their creation timestamps. However, performing a scan to retrieve this information can be highly inefficient, especially for extensive datasets, as it reads every item in the table. In this guide, we’ll delve into an effective strategy to fetch the top 10 records without using scan operations, leveraging the power of Global Secondary Indexes (GSI).

The Problem Statement

Imagine you have a DynamoDB table configured as follows:

Primary Key (PK): productID

Attributes: name, description, url, createTimestamp, etc.

You want to retrieve the latest 10 products sorted by their createTimestamp, similar to the SQL query:

[[See Video to Reveal this Text or Code Snippet]]

This requirement poses a challenge because using a scan for retrieval would not be optimal due to performance issues, particularly with large amounts of data frequently accessed by users.

Understanding the Solution Using GSI

Creating a Global Secondary Index

To efficiently solve this problem, you can create a Global Secondary Index (GSI). This index will help you access your data in a sorted manner based on the createTimestamp attribute while avoiding the need for a scan operation. Here’s how to set it up properly:

Partition Key (PK): A constant value (e.g., 'Products')

Sort Key (SK): createTimestamp

This setup allows you to "bucket" all your product items under the same partition key, enabling you to retrieve and sort them based on creation timestamps efficiently.

Considerations for Write Throughput

If your application experiences high write rates (over 1,000 write units per second), you should consider sharding your partition key value. Sharding means distributing your data across multiple partitions to enhance the write capacity. Here’s how it works:

Choose N randomly selected values to be your partition keys, e.g., Products1, Products2, ..., ProductsN.

During each write operation, randomly assign products to one of these partition keys.

Making Queries

Once the GSI is in place, querying it becomes straightforward. To fetch the latest 10 products, you will perform a query operation like the following:

Query the GSI using the constant partition key.

Set the sort order to descending based on createTimestamp.

Limit the results to the top 10 records.

This method ensures that each query is efficient, on-target, and optimized for performance.

Summary

To summarize, to effectively retrieve the latest 10 records from a DynamoDB table based on a sorting attribute without resorting to a scan, consider the following steps:

Create a Global Secondary Index with a constant partition key and a sort key for createTimestamp.

If handling high write rates, implement sharding for the partition key.

Use query operations against the GSI to fetch the latest products efficiently.

This approach not only adheres to best practices in performance optimization for DynamoDB but also aligns with common design patterns used in similar scenarios. By structuring your queries this way, you maximize the efficiency and responsiveness of your applications.

Embrace these techniques to ensure a smooth and efficient experience for users accessing your DynamoDB-backed application!

Видео How to Fetch the Latest 10 Records in DynamoDB Without Using Scan канала vlogize