# Inefficient Use of RDS Reader Nodes

Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/inefficient-use-of-rds-reader-nodes

[Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) 

# Inefficient Use of RDS Reader Nodes

## Explanation

RDS reader nodes are intended to handle read-only workloads, allowing for traffic offloading from the primary (writer) node. However, in many environments, services are misconfigured or hardcoded to send all traffic-including reads-to the writer node. This results in underutilized reader nodes that still incur full hourly charges, while the writer node becomes a performance bottleneck and may require upsizing to handle unnecessary load. This inefficiency reduces cost-effectiveness and resilience, especially in high-throughput or scalable architectures.

## Relevant Billing Model

Per-instance hourly cost for each provisioned writer and reader node

## Detection

- Review whether the resource has been actively used over a representative time period

- Compare the volume of read traffic across reader nodes vs. the writer node

- Identify services that are hardcoded to target the writer node for both read and write operations

- Evaluate whether the presence of reader nodes is necessary if they are consistently underutilized

- Assess application architectures for abstraction layers or configuration patterns that bypass proper routing to readers

## Remediation

- Refactor application logic or database client configurations to route read traffic to reader endpoints

- Introduce or enhance query routing layers (e.g., using database drivers with read/write splitting support)

- Remove reader nodes if there is no realistic path to utilizing them efficiently

- Monitor reader vs. writer utilization continuously to ensure traffic is appropriately distributed

## Relevant Documentation

[Amazon RDS Read Replicas](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html) 
[Best Practices for Amazon RDS](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_BestPractices.html)

[Submit Feedback](https://hub.pointfive.co/inefficiencies/inefficient-use-of-rds-reader-nodes)

## At a glance

Reference

CER-0205

Cloud provider

AWS

Service

AWS RDS

Category

[Databases](https://www.pointfive.co/efficiency-hub/service-category/databases)

Inefficiency type

Suboptimal Workload Distribution

## Contributed by

- Jim Bendoraitis 

### Jim Bendoraitis

Senior Manager, Platform Engineering @ United Airlines

[LinkedIn](https://www.linkedin.com/in/jim-bendoraitis-44b798b1/)

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Source: the public page above. Product screenshots and illustrative interfaces are examples, not live customer data.