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

[korsikov]

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!

[David_Friend]

@korsikov have you reviewed this KB already:
https://community.qlik.com/t5/Official-Support-Articles/Qlik-Sense-Engine-Enterprise-on-Windows-How-...

[korsikov]

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

[David_Friend]

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

[korsikov]

@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

[David_Friend]

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?

[korsikov]

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.