Performance issues and errors when opening apps

[Suzanne_van_der_Tang]

During the last 2 weeks, our Qliksense production environment encounters a serious performance issue.

Symptoms:

- In mornings it takes quite a while to open an app. On screen the message "initializing" is displayed for a long time, and then, after a while, it shows "App is opened" for a while.

- The HUB screen shows an error message after a couple of minutes, stating something like "Error has occurred, connection timed out because of inactivity".

- Once the app finally opened, it works as expected (not very slow).

- Our test environment (other server) works fine (no errors, less users, but same amount of data).

- After the qlik services have been restarted, the system works fine again.

- Next morning, the system is slow again, and needs to be restarted all over again.

- Nprinting and Qlik tasks are running without issues.

Anyone has a clue as to where we should look to investigate/solve this issue?

[mpc]

Hi, 

First of all, is there any change on the server ? (Windows or NET framework update, Qlik Sense, or other) ?
Then, to troubleshoot the performance issue, you'll need to monitor CPU/RAM/Disk usage, and Qlik Sense activity. You need to check network related issue too, if the apps are store on a network location. 
You can also check in the Qlik Sense logs something happend when you open the app. Check the Windows Event viewer too. 

Regards 

[Hazel_K]

Hi Suzanne,

This sounds very similar to the issue we're experiencing at the moment. Did you discover the cause?

Kind regards

Hazel

[Hazel_K]

Just to add - we found the cause of the issue to be the anti virus program on the server, and updating it following this document solved the problem:

https://help.qlik.com/en-US/sense-admin/May2024/Subsystems/DeployAdministerQSE/Content/Sense_DeployA...

Thanks

Hazel

[Suzanne_van_der_Tang]

Unfortunately, this hasn't solved the issue on our system. 3 months already now, every day a restart...

Any other suggestions?

[Suzanne_van_der_Tang]

Hi,

Thanks for your response! We've checked quite some things already, also our external Qlik advisor has been involved in finding the issue. We've raised a call at Qlik now, hopefully we'll get the answer quickly now, as this is getting quite annoying...

[Hazel_K]

Hi Suzanne,

That does sound annoying. I just followed the video in this document, I've installed some of the extra monitoring apps to check, but to be honest the anti virus issue didn't show up anything in the logs/apps, it was more a case of trying it and hoping it would make a difference. 

https://community.qlik.com/t5/Official-Support-Articles/How-to-start-investigating-Qlik-Sense-Perfor...

Good luck.

Thanks

Hazel

[lvdbrink]

The symptom of apps opening slower in the morning when they are first opened is natural behaviour for Qlik. When a user opens an app for the first time in a while, the data model of the app is loaded into the cache (your RAM memory). The larger the app is, the more time it takes to do so. When the app is opened the second time by a user shortly after, the app is still in the cache and thus loads faster.

A way to mitigate this is by enabling app preload for larger apps. You can learn how to do this here. More info on determining what apps to apply this to you can find here.

In general, it might be worth to investigate the RAM usage of your server. It might be that your server has too little of it, causing issues when more and more apps are loaded into the cache during the day.

[Suzanne_van_der_Tang]

Hi,
Thanks for your response! Unfortunately, it's not "the usual first startup". For 2 minutes, an app says "initializing", and after that it start. If I open the same app again, the same thing happens. After the services have been restarted, the issue is solved. Until midnight, then it's back again...

[lvdbrink]

Might still be related to RAM issues. I would start by investigating the engine and event logs and see if there is any warnings around the time you try to open these apps. See this support article for tips on how to start investigating this.

Additionally, you mentioned NPrinting tasks. Is the NPrinting server installed on a separate server or is it on the same server as Qlik Sense? If they are on the same server, there might be some conflicts occurring between the 2 (best practice is to have them on separate servers).