Skip to main content

GraphQL–Always monitor the operational complexity

Today GraphQL is a mature alternative for building API's. Many developers have discovering its flexibility, expressiveness, and efficiency. However, with this flexibility comes the challenge of managing and tracking operational complexity, especially as APIs scale. Without proper monitoring and optimization, GraphQL queries can become performance bottlenecks, leading to slow response times, server overload, and a suboptimal user experience. Therefore it is important to monitor the Operational Complexity of the queries send to your API endpoint.

What is Operational Complexity in GraphQL?

Operational complexity in GraphQL refers to the computational and resource costs associated with executing a query. Unlike REST, where each endpoint is typically associated with a fixed cost, GraphQL's flexible nature means that the cost can vary dramatically depending on the structure of the query.

For instance, a simple query fetching a list of users might be relatively cheap. However, if the same query requests deeply nested fields or multiple relationships, the server may need to execute numerous database joins, resulting in a high operational cost. Without careful monitoring, this can lead to performance degradation, especially in large-scale applications.

Why You Should Track Operational Complexity

There are multiple reasons why tracking the operational complexity is important:

  1. Performance Optimization: Understanding the operational complexity of your queries allows you to optimize performance. By identifying high-cost queries, you can optimize your resolvers, refactor your schema, or implement caching strategies to improve efficiency.

  2. Server Stability: High operational complexity can strain your server resources, leading to increased response times, higher latency, and potential downtime. By tracking complexity, you can prevent these issues before they escalate.

  3. Better User Experience: Slow API responses can frustrate users and degrade the overall experience of your application. By keeping operational complexity in check, you ensure a smoother, faster user experience.

  4. Cost Management: In cloud environments, server resources are directly tied to costs. High-complexity queries that consume excessive CPU, memory, or database resources can lead to higher infrastructure costs. Monitoring complexity helps you manage these expenses effectively.

Operational Complexity in HotChocolate

HotChocolate offers specific middleware that allows you to track the operational complexity of an operation. By default every field is assigned a complexity of 1. The complexity of all fields in one of the operations of a GraphQL request is not allowed to be greater than the maximum permitted operation complexity.

So by default, the following query will have a cost of 2 (1 for the books field + 1 for the title field):

This maximum can be configured in your GraphQL bootstrapping code:

However some fields have a higher cost then others. In the books example above, it seems logical that the cost of fetching a book is higher than the cost of the title field inside a book. To take this into account we can assign a different complexity through the cost directive:

The total cost of the query now becomes 11 (10 for the books field+ 1 for the title field).

Track Operational Complexity in HotChocolate

To track the operational complexity in HotChocolate, I make use of the built-in OpenTelemetry integration:

More information

Operation Complexity - Hot Chocolate - ChilliCream GraphQL Platform

Instrumentation - Hot Chocolate - ChilliCream GraphQL Platform

    Popular posts from this blog

    Azure DevOps/ GitHub emoji

    I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.

    Kubernetes–Limit your environmental impact

    Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t...

    DevToys–A swiss army knife for developers

    As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities.  DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Col...