Skip to main content

RedisTimeoutException - High ‘in’ value

While investigating a performance issue we noticed that the we had a lot of RedisTimeoutExceptions inside our logs:

2019-12-15 16:26:57.425 +01:00 [ERR] Connection id "0HLS1E3OEP520", Request id "0HLS1E3OEP520:0000001D": An unhandled exception was thrown by the application.

StackExchange.Redis.RedisTimeoutException: Timeout performing PEXPIRE CookiesStorageAuthSessionStore-4a07a1bb-04e0-442d-9223-e1612967bf2b, inst: 2, queue: 8, qu: 0, qs: 8, qc: 0, wr: 0, wq: 0, in: 14411, ar: 0, clientName: SERVER1, serverEndpoint: Unspecified/redis:6379, keyHashSlot: 4822 (Please take a look at this article for some common client-side issues that can cause timeouts: http://stackexchange.github.io/StackExchange.Redis/Timeouts)

You would think that this indicates there is a performance issue in Redis but this turned out not to be the case.

Let’s have a second look at the error message and especially the strange parameters: inst: 2, queue: 8, qu: 0, qs: 8, qc: 0, wr: 0, wq: 0, in: 14411, ar: 0

In this situation you have to notice the high ‘in’ value. This value tells us how much data is sitting in the client’s socket kernel buffer.  This indicates that the data has arrived at the local machine but has not been read by the application yet.

So the problem should not be found inside Redis but in the application(or server) that is consuming Redis.

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