Skip to main content

ASP.NET Core–Performance tip

Question: What is wrong with the following ASP.NET Core controller:

No idea?

Take a look at the return type...

Returning IEnumerable from an action results in synchronous collection iteration by the serializer. The result is the blocking of calls and a potential for thread pool starvation.

One possible way to avoid this is by explicitly invoking ToListAsync before returning the result:

Starting from ASP.NET Core 3.0 you can also use IAsyncEnumerable<T>. This no longer results in synchronous iteration and is as efficient as returning IEnumerable<T>.

Let’s rewrite the example above to use IAsyncEnumerable<T>:

REMARK: If we take a look at the original example again, it will not be an issue in ASP.NET Core 3.0 or higher. Why? Because we allow the framework to choose how to handle the IQueryable<T> we get back from the Where() clause. In the situation we are using ASP.NET Core 3.0 or higher the results will be buffered and correctly provided to the serializer. However this is implicit behavior that doesn’t work in all situations(it depends on the underlying types used).

More information and other performance tips can be found here: https://docs.microsoft.com/en-us/aspnet/core/performance/performance-best-practices

Labels:

Popular posts from this blog

.NET 8–Keyed/Named Services

A feature that a lot of IoC container libraries support but that was missing in the default DI container provided by Microsoft is the support for Keyed or Named Services. This feature allows you to register the same type multiple times using different names, allowing you to resolve a specific instance based on the circumstances. Although there is some controversy if supporting this feature is a good idea or not, it certainly can be handy. To support this feature a new interface IKeyedServiceProvider got introduced in .NET 8 providing 2 new methods on our ServiceProvider instance: object? GetKeyedService(Type serviceType, object? serviceKey); object GetRequiredKeyedService(Type serviceType, object? serviceKey); To use it, we need to register our service using one of the new extension methods: Resolving the service can be done either through the FromKeyedServices attribute: or by injecting the IKeyedServiceProvider interface and calling the GetRequiredKeyedServic...
Read more

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.
Read more

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...
Read more