topic Re: Is it memory leak or some special feature? in QlikView

Is it memory leak or some special feature?

Mon, 28 Oct 2013 17:02:45 GMT

I've got a situation when I maximize one of my charts in a dashboard. The dashboard is pretty big - 55.5 Gb.

What do you expect usually? Right the memory starts to grow for sorting/aggregation and etc.

What's next? QV allocates necessary RAM and starts doing calculation magic when your dashboard is not clickable (grayed)

So, as you can see it reached 80.8 Gb point. What is next? The chart should be rendered and memory should be freed.

But what I see? It's still there. Chart is ready, the dashboard is available, I can run something new, navigate everywhere, but memory is still busy.

Ok, what we usually do when memory is busy? Right, we try to close the dashboard.

But what I've got is pretty strange - the dashboard is closed, the Start Page only. The empty QV Start Page holds 27.5 Gb RAM from previous dashboard calculation.

And the only way to free RAM is to close whole QV application instance.

Did I miss something or it's expected behavior?

I'm running this version of QV.

On this OS and Server.

Re: Is it memory leak or some special feature?

hic — Tue, 29 Oct 2013 13:34:33 GMT

It is expected behaviour. QlikView does not release allocated memory to Windows after each calculation. If it did, the memory would soon become fragmented. Instead it reuses the memory for the next calculation or for its internal cache. If you want to control the amount of memory QlikView is allowed to grab, you should change the Working Set Limits under User Preferences.

HIC

Re: Is it memory leak or some special feature?

Fri, 15 Nov 2013 12:11:21 GMT

What you are describing is a running application behavior. But look at the picture when I closed the application. 27.5 Gb are still in a memory. About what calculations we can talk if there is no running applications anymore?

Re: Is it memory leak or some special feature?

hic — Fri, 15 Nov 2013 12:19:40 GMT

The cache is not tied to a specific qvw-file. It is common for all files. So, yes, QlikView will keep allocated memory also when the file is closed.

HIC

Re: Is it memory leak or some special feature?

Fri, 15 Nov 2013 13:01:51 GMT

I have another question then. Why when I try to load a second dashboard which require all the rest of the memory plus what QV uses for cache, the dashboard is crashing because of OUT OF MEMORY issue? And I don't have this problem when there is no cache allocated by QV.

Re: Is it memory leak or some special feature?

hic — Fri, 15 Nov 2013 13:41:16 GMT

I don't know why it crashes. I can of course not rule out that there could be a bug that causes this. All I am saying is that the fact that QlikView doesn't de-allocate memory, is not a sign of a bug. It is the way QlikView is designed.

Concerning the OUT OF MEMORY: Often when this happens, it is one single object that requires too much memory. It could be that it has too many dimensions, that it is corrupt, or that the calculations that it has to make to show anything just takes too much memory. Try to figure out which object it is and then check how much memory it uses when you open the app as first app in a clean environment.

HIC

Re: Is it memory leak or some special feature?

Fri, 15 Nov 2013 14:17:28 GMT

It's not about an object out of memory. It's about whole dashboard.