DynamoDB Cost Optimization: Enhancing Efficiency for Optimal Resource Utilization

December 4, 2023
min read
Cloud Optimization

Ever feel like you're pouring more money than needed into AWS DynamoDB? You're not alone. Many businesses use DynamoDB, but few truly know how to capitalize on its pricing model to minimize spending while maximizing efficiency in AWS DynamoDB cost. Our topic today is all about DynamoDB cost optimization strategies, a niche yet crucial concept for businesses leveraging Amazon's robust NoSQL database service. Strap in as we explore practical tips, advisories, and guidance to help you reduce DynamoDB costs and get the best bang for your buck. Be it through capacity planning, optimizing data structures, or leveraging DynamoDB's features smartly; we'll traverse all these paths together. 

Let's begin our journey toward DynamoDB cost optimization, shall we?

What is DynamodDB?

In case you're new to this term, Amazon DynamoDB is a revolutionary database service under the expansive Amazon Web Services (AWS) umbrella. It's a NoSQL database designed with scalability and high performance in mind, perfect for tech-savy businesses aiming at growth. Amazon DynamoDB is serverless, meaning there's no need for you to manage any servers, and the database service takes care of all the logistics for you.

Amazon DynamoDB stands out due to its abundant features. It offers top-notch data encryption for maximum security and automatic backups to prevent data loss. Its cross-regional replication ensures your database is always available and intact, regardless of location. Its in-memory caching system quickens the data retrieval process. Plus, DynamoDB provides simple tools for efficient data importing and exporting, easing the process of data management. Implementing AWS DynamoDB cost optimization ensures that you not only benefit from these features but also optimize your expenses effectively.

But let's address a critical question you may have – What about the cost? Well, Amazon DynamoDB could seem pretty expensive, given all the impressive features it brings to the table, but there's no need for panic! You can harness the power of Amazon DynamoDB without straining your budget by prioritizing effective AWS DynamoDB cost optimization strategies. Take a deep breath, and let's explore some clever strategies to optimize your DynamoDB costs:

How Does DynamoDB Calculate Price?

Amazon's DynamoDB calculates its costs based on the amount of data you read, write, or store in your DynamoDB tables, alongside any extra features you might use. Employing effective AWS DynamoDB cost optimization strategies becomes essential to manage and control expenses associated with these data processing operations.

When dealing with Amazon DynamoDB, you have two pricing options at your disposal, which play a significant role in how you can reduce DynamoDB costs

On-demand capacity mode

This mode allows you to pay-as-you-go, billing you only for individual requests to read and write data. There's no need to anticipate your application's read-and-write requirements as DynamoDB spontaneously accommodates fluctuating workloads.

Here are some key points about how on-demand capacity mode pricing is calculated in DynamoDB:

  • Charges based on the actual number of requests made: Every read and write operation to your database is counted as a "request" and the cost is calculated accordingly.
  • Differentiating between read and write requests: DynamoDB considers read and write operations dissimilarly. A "write request" for DynamoDB means writing 1 KB of data or less, whereas a "read request" means reading 4 KB of data or less. Thus, larger requests are charged more.
  • No up-front costs involved: You pay only for what you use. You are not charged any operational overheads or capacity planning fees. Furthermore, there are no minimum fee requirements.
  • Data transferring charges: DynamoDB applies data transfer charges, but only when data is transferred "out" to the internet or between AWS regions. Data transfer “in” and within the same region is free.
  • Backup and restore charges: DynamoDB charges extra for data backup, restoration, and any increase in storage usage due to these operations.
  • Global table charges: If you choose to replicate your tables in multiple regions using the global tables feature, DynamoDB will charge for replication along with normal read and write operations costs.

Provisioned Capacity Mode

This pricing option lets you determine the number of data reads and writes your application will require per second. To effectively maintain your application's performance and simultaneously reduce cost of DynamoDB, the auto-scaling feature is also available. It adjusts your table’s capacity based on a specified utilization rate.

When using the Provisioned Capacity Mode for DynamoDB, your cost is calculated based on a few key factors:

  • Provisioned Read Capacity Units (RCU): You will be charged for the number of reads per second your application requires. A single RCU provides you with the ability to read up to 4KB per second.
  • Provisioned Write Capacity Units (WCU): This component of the pricing pertains to how many writes per second your application will make. One WCU allows you to perform one write per second for an item up to 1KB in size.
  • Storage Costs: Beyond the read and write capacities, you will also be charged for data storage. This fee covers the storage of your tables and any associated indexes. It is charged per GB-month. It also covers the cost of data transfer in and out of dynamoDB.
  • Optional features: Optional features such as DynamoDB Streams or Global Tables will incur additional costs. Similarly, the backup and restore services provided by DynamoDB are not included in the base price and will result in further charges.

Knowing how these factors influence your overall expenditure is crucial in effectively managing your costs with DynamoDB Provisioned Capacity Mode.

Cost-Saving Tactics for DynamoDB Usage

In the realm of cloud computing, optimizing database utilization is paramount for both efficiency and cost-effectiveness. As organizations increasingly leverage serverless databases like Amazon DynamoDB to manage their workloads, implementing judicious cost-saving tactics becomes essential. Before delving into the main strategies for DynamoDB usage, it's crucial to recognize that similar considerations extend to other cloud providers. For instance, on Google Cloud Platform (GCP), analogous principles apply to services, where strategic GCP cost optimization is pivotal for harnessing the full potential of these serverless database solutions. Now, let's explore key strategies for optimizing DynamoDB costs and enhancing overall operational performance.

1. Effective Use of Read and Write Capacity Units (RCUs and WCUs)

Optimizing your usage of Read and Write Capacity Units (RCUs and WCUs) is a critical approach to managing your DynamoDB costs effectively. These units are basic measures of your database's performance capacity, and understanding how they are consumed can lead to significant cost savings.

DynamoDB uses 'units' to represent provisioned capacity, crucial for cloud cost optimization. Understanding Read Capacity Units (RCUs) and Write Capacity Units (WCUs) is essential in this regard.

  • Read Capacity Units (RCUs): A single RCU represents a consistent read per second for up to 4KB. For example, reading an 8KB item requires 2 RCUs. It's important to avoid over-provisioning and accurately assess workload requirements to minimize costs.
  • Write Capacity Units (WCUs): Each WCU allows for one write per second for data items up to 1KB. Writing an item of 2KB, therefore, needs 2 WCUs. Understanding the nature and frequency of write operations is key to avoiding unnecessary WCUs.


  • Billing Increments: Read and write usage is charged in increments, and charges apply even if the full increment isn't used.
  • DynamoDB Query Efficiency: Using Query to fetch multiple items in one request consumes fewer RCUs than reading each item separately.
  • Read Request Categories: There are two types - Strongly consistent and Eventually consistent, with the latter using half as many RCUs.
  • Charges Based on Data Read: DynamoDB charges are based on the data read, not delivered. Filter expressions don't impact costs.

Tips for Reducing Costs

  • Opt for Eventually Consistent Reads: These reads use half the RCUs compared to strongly consistent ones, providing similar performance levels.
  • Choose Operations Wisely: DynamoDB operations like Scan and Query consume more units than others like GetItem or PutItem. Selecting operations smartly can lead to reduced capacity usage.
  • Efficient Data Indexing: Access fewer items more frequently to enhance read/write capacity, thereby reducing costs.

Improving Write Costs

  • Billing in 1 KB Increments: Writes are billed in 1 KB increments. Reducing the size of items to consistently below 1KB can be cost-effective.
  • Optimization Techniques:
  1. Use binary data types and apply compression.
  2. Represent dates using numbers or bytes.
  3. Adopt shorter attribute names.

Note: DynamoDB charges for write operations are based on the item's size before or after the operation. All WCU charges apply irrespective of condition expression outcomes. Transactions double WCU usage due to the two-phase commit system.

2. Make Smart Use of Auto Scaling

Putting DynamoDB autoscaling to work for you can be a strategic move in the realm of DynamoDB cost optimization. This feature is designed to tweak your read and write capacity based on the demands of your application - increasing during peak times and reducing when demand is low. This way, cost efficiency is maximized, helping to reduce DynamoDB costs.

Handling database scaling can be quite a challenge due to the unpredictable characteristics of workloads. While understaffing can risk your operation's success, going too big can lead to waste. But DynamoDB helps streamline this task by adjusting the read and write throughputs in harmony with your application's needs. Any shift in your workload is thus automatically compensated for as DynamoDB recalibrates and reapportions your database partitions.

When you start a DynamoDB table, autoscaling is enabled by default, but you can also choose to enable it for other tables. In DynamoDB, you outline autoscaling by setting the lower and upper limits for the read and write capacity, along with a target utilization percentage. Autoscaling goes into action when usage either surpasses the target by 2% continuously for two minutes or dips below the target, with a buffer of 20%, consistently for fifteen minutes.

Let's delve into how this functions for both capacity modes:

  1. Provisioned Capacity Mode:
  • Auto Scaling: In this setting, you pinpoint the read and write capacity you anticipate your application will need. DynamoDB Auto Scaling is then engaged to automatically adapt capacity in keeping with the defined utilization rate, managing traffic while keeping costs low.
  • How it Works: You establish lower and upper capacity limits and a target utilization rate. DynamoDB Auto Scaling will automatically alter the allotted throughput within these confines based on actual usage. This is perfect for workloads with predictable patterns or when reducing DynamoDB costs is a priority.
  • Manual Adjustment: You still have the option to manually tune the provisioned throughput settings, which don't impact the current auto-scaling policies.
  1. On-Demand Capacity Mode:
  • Auto Scaling: With On-Demand mode, the read and write capacity of the table or indexes automatically scales to tackle the workload. This mode doesn't require capacity planning or throughput oversight.
  • How it Works: DynamoDB instantaneously supports your workloads as they increase or decrease to any previously experienced traffic amount. This model is designed to manage unpredictable workloads by providing smooth scaling.
  • Cost Implications: Your bill is based on the actual read and write requests generated by your application without having to predefine throughput capacity.
  • No Manual Scaling: In On-Demand mode, no auto-scaling policies are necessary as DynamoDB takes care of the scaling swiftly and automatically.

3. Minimize Storage of Large Items in DynamoDB

If your DynamoDB costs are escalating due to the storage of large values or images, here are a couple of strategies that can help mitigate the problem and contribute to DynamoDB cost optimization:

  • Compress attribute values that are large in size

To decrease the size of the items being stored and, as a result, reduce your storage costs, you might want to look into leveraging compression algorithms such as GZIP or LZO.

  • Reserve Amazon S3 for the storage of large objects

When it comes to storing hefty objects cost-effectively and durably, Amazon S3 shines. With this approach, you would first write the large object into an S3 bucket. Then, you create an item in DynamoDB that stores the identifier of that object, for example, a pointer towards the S3 URL of the object. This method prevents skyrocketing storage costs incurred when storing large images or objects directly in DynamoDB. Instead, you can simply store the object's URL in DynamoDB while keeping the object itself in S3. If there is absolutely no getting around storing the objects in DynamoDB, make sure you compress them to the maximum extent possible to keep storage costs in check.

4. Implement Reserved Capacity

If you're utilizing the provisioned capacity mode and your capacity exceeds 100 units, you might want to think about investing in reserved capacity. This can prove to be quite cost-effective, playing a pivotal role in DynamoDB cost savings. Specifically, for a three-year term, this choice would render a substantial discount of 76%. Opting for a one-year term isn't too bad either, offering a significant 53% discount when compared with the cost of provisioned throughput capacity. This approach is key in managing AWS DynamoDB costs and can significantly reduce DynamoDB costs over the long term.

5. Select the Appropriate Table Class

Cost optimization with DynamoDB can be further enhanced by choosing one of the two table classes it provides:

  • Standard Table Class:

This is the default class. It strategically balances storage and read/write costs, providing an optimal baseline.

  • Standard-Infrequent Access Table Class:

This table class can reduce your storage costs by up to 60%, though read/write costs maybe 25% higher compared to the Standard Table Class. It’s an excellent option if your application doesn't frequently require read/write operations In addition, there are no performance trade-offs, and the Standard-IA tables offer the same durability, availability, performance, and scalability as existing DynamoDB standard tables, making it a strategic choice to reduce DynamoDB costs.

Remember to focus on your application's balance between storage and throughput usage when deciding on the table class. Keep in mind that the chosen table class will likely impact other pricing aspects such as Global Table and GSI costs.

6. Use AWS Cheaper Regions

Choosing a more cost-efficient AWS region can significantly cut down your DynamoDB expenses, which is a crucial aspect of DynamoDB cost savings. If the location of your data is flexible, consider opting for the most affordable region.

  • You're not tied to any specific region
  • Your decision won't impact the speed of data reads or writes
  • There's no need to worry about meeting specific regulatory or compliance standards

Some of the most budget-friendly AWS regions include us-east-1, us-east-2, and us-west-2. They offer great value with costs of $0.25 per GB/month, $0.00065 per WCU/hour, and $0.00013 per RCU/hour, respectively.

This approach allows for effective AWS DynamoDB cost management, helping to reduce DynamoDB costs without compromising on the functionality and efficiency of your application.

7. Prioritize Queries Over Scans

In DynamoDB, the methods for reading data come in dual forms: through queries or scans. While a query focuses on seeking out a specific primary or index key, a scan, on the other hand, rummages through the entirety of a database table to find a result. As such, when you execute a query, the costs in terms of Read Capacity Units(RCU) are only tied to the items retrieved.

However, running a scan paints a different financial picture. In this case, you will be charged for each row that gets scanned, irrespective of the number of items ultimately returned. This difference can greatly impact your DynamoDB costs.

8. Optimally Utilize GSIs (Global Secondary Indexes)

When opting to use a Global Secondary Index (GSI), take note that it comes with its own separate provisioned throughput settings and carries no restrictions on size. However, to prevent GSI pertaining costs from escalating, it's recommended to only project the truly necessary attributes instead of projecting all.

This strategy effectively reduces both the storage costs and read-write charges to their minimum, thereby helping to reduce DynamoDB costs. It happens by shrinking the volume of data needing access and updates. Additionally, refrain from creating indexes on attributes that find scarce usage. For your convenience, these access patterns can be monitored via the metrics available in DynamoDB.

9. Use TTL to Remove Unneeded Items

Take advantage of DynamoDB's Time-to-Live functionality to automatically delete old or unnecessary items from your tables. This way, you can effectively reduce your storage costs. Best part? It's completely free of charge!


Optimizing the costs of DynamoDB usage can be a multifaceted approach that touches on strategic capacity planning, wise data management, and region selection, among other factors. DynamoDB cost optimization is crucial for efficient resource utilization. It is imperative to comprehend DynamoDB's pricing model and judiciously leverage available cost-saving tools and features. The key lies in understanding the workings of DynamoDB and strategizing its use in a manner that's most beneficial to your specific requirements and goals.

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