Increasing the "App chache time" vs. cache initializer

[David_K1]

Hi everyone,

We have a Qlik Sense environment (QS Enterprise on Windows) where almost 100% of all users will only use 2 Apps, and we would like these Apps to open as fast as possible. Currently we observe that App opening takes much longer for the first user in the morning on every node (we have 6 nodes). I am assuming that is because the "app cache time" is set to 8 hours, so the apps are cleared from the cache every night. 

Now we are thinking about using a cache initializer to load these 2 apps every morning. However I am wondering: couldn't we simply increase the "app cache time" to 1 week (or longer...) and have the same result? Are there any drawbacks to increasing the app cache time that much?

Many thanks in advance!

[Or]

1) It'll impact every app, not just the two that are primarily in use

2) I'm not 100% sure about this, but I believe increasing the app cache timer won't make it faster for the first person to access the app after a reload

[Levi_Turner · Accepted solution]

To add on to the comment by @Or , the app cache time is a global setting which keeps an app in-memory for the specified time after the last session. This will apply to all apps open in RAM. If you truly only have 2 apps in the environment, then this distinction does not matter. But in most environments, there are many more than this.

To use an example, if there's an 8 hour app cache time. When the first user opens the app at 8AM, the app will stay in memory 8 hours after their session ends. The earliest it would leave memory is at 4:01PM.

Adjusting this configuration makes sense when you want to ensure that any opened application stays in memory throughout your user's business hours.

When it comes to cache warming (the cache initializer is just one tool to achieve this functionality), this programmatically opens the app into memory. To connect this technique with the app cache time, let's pretend that you used a cache warming technique to open the app at 7:59AM so that the user(s) who open the app at 8AM, will retrieve the app from memory. This means that the app will stay in memory (from the app cache time) 8 hours after the last user's session. The earliest it would leave memory is 4:01PM.

For your use-case (as written), I would do the following:

• Increase the app cache time to cover your user's business hours (most organizations have at least 9 business hours; more if your users are in different time zones)
• Cache warm the app before the user's business hours start

This ensures that the first user opens the app from memory and that all subsequent sessions throughout the business day retrieves the app from memory.

Be sure to consider the note about multi-node environments here in your environment.

[David_K1]

Thank you @Or  and @Levi_Turner  for the helpful replies.