topic Re: Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense in Management & Governance

Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense

korsikov — Mon, 17 Mar 2025 10:29:58 GMT

I am observing that Qlik Sense apps are being unloaded from the server's RAM with the following message:

DOC loading: Unloading document 86c9299d-dd03-4bbf-beaa-6bff423271d6, state UNLOADING overload mode.

It seems that when the system lacks resources, it may unload documents that have no active user sessions earlier than the specified timeout.

According to the documentation, the App cache time (seconds) setting represents:

The number of seconds that a Qlik Sense app is allowed to remain in memory, after the last session that used the app has ended.

I understand that "allowed" in this context likely means that the app can remain in memory, but there is no guarantee that the memory will not be cleared earlier. I am also noticing mass unloading of documents, where several documents in a row are being unloaded with the message:

Sometimes I see that the session ends and the document is closed immediately.

How can I understand the cause of this behavior? What exactly is "overload mode," and how can I get more information about it?

Any insights or advice would be greatly appreciated!

Re: Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense

David_Friend — Mon, 17 Mar 2025 13:02:11 GMT

@korsikov have you reviewed this KB already:
https://community.qlik.com/t5/Official-Support-Articles/Qlik-Sense-Engine-Enterprise-on-Windows-How-the-memory-hard-max/ta-p/1717228

Re: Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense

korsikov — Mon, 17 Mar 2025 13:17:35 GMT

Thank you for attention to my issue.

You mean " If an app is opened at 90% usage on this node and hasn't otherwise been load balanced previously, what will happen is that the app will open while Qlik attempts to aggressively clean memory out to get back to the minimum value. This can still result in a memory overload, but does not have to."

how can I get more information about it?

I can't find any more information in the Qlik logs about the system being in “overloaded” status

Re: Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense

David_Friend — Mon, 17 Mar 2025 13:58:32 GMT

I have not found anything specific yet on that I'll keep looking, how much RAM does that server have?

Re: Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense

korsikov — Mon, 17 Mar 2025 14:18:04 GMT

@David_Friend Server has 32Gb Ram. Total Mem usage ~ 28Gb/32Gb

Zabbix info last 1 day : Free memory Last 5.32 / Min 2.76 Gb / avg 7.01 Gb / max 10.21 Gb

Wokring set limits is Min 75% and 92% Max. App cache time default 28800 sec. I'm never see in Engine Health - Saturated YES

Re: Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense

David_Friend — Mon, 17 Mar 2025 15:23:25 GMT

Without knowing your environment, size of your apps etc. I would say that 32 is not very much for a QlikSense server. Its possible this small amount of RAM could be creating the issue since QlikSense will do its best to clean up RAM usage.

@Sebastian_Linser I can't find anything about that message, does that look familiar to you?

Re: Understanding "Overload Mode" and Unexpected App Unloading in Qlik Sense

korsikov — Mon, 17 Mar 2025 15:28:14 GMT

I completely understand. It is not possible to judge only from the amount of memory whether it is enough or not. Sizing is a complicated issue. I will say one thing, the server always stays within the physical memory and does not go into swap.
In general, I want to understand under what conditions “overloaded mode” occurs, and how Qkik behaves in such cases.