topic Re: QVW Performance in QlikView

QVW Performance

userid128223 — Tue, 18 Feb 2014 16:09:02 GMT

We have QVD that was working fine until data grew and now taking lot longer to respond and generally sluggish with user interaction.

When troubleshooting performance.

What's the starting point, what do you look at first, second and then down the list.
What tools can you use.
Any other ideas.

Re: QVW Performance

alexandros17 — Tue, 18 Feb 2014 16:12:41 GMT

I've experienced the same problem:

1) At first avoid syntetic keys if possible

2) review all the expression (try to understand which object is slow) and replace if with set analysis

3) If possible review the cloud, try to compute values in script in order to write lighter expression

Hope it helps

Re: QVW Performance

userid128223 — Tue, 18 Feb 2014 16:19:45 GMT

1) There is no synthetic key.

2) How do you determine or monitor which objects is slow. is there an app to do that.

3) I have used document analyzer to check if there are any fields that we are pulling that is unused.

4) So generally speaking IF statements are slower then set analysis?

5) Is there advantage disadvantage to moving calculation to script area vs object.

Re: QVW Performance

Tue, 18 Feb 2014 16:31:45 GMT

2) Document Properties / tab Sheet / there is a Calc Time

(but the object must be drawn at least once)

4) Yes, Sum(IF () ) will compute everything (because there is a check on every row)

A set analysis creates a scopes and reduces the amount of computed data. the gain may be substantial.

When doing comparison in the IF(), it is better to compare versus an integer (a string comparison is slower)

5) if you can move some calculation to the backed it can be good, like Flags ... that you will use in the set analysis

Fabrice

Re: QVW Performance

alexandros17 — Tue, 18 Feb 2014 16:34:23 GMT

Unfortunately I don't know any monitor for objects.

If is really slower than set analysis

If you move computing operation in script you will have data yet available in expresions that will have not to compute anything or at least the conputing time / operation will be reduced

Re: QVW Performance

userid128223 — Tue, 18 Feb 2014 16:39:07 GMT

Thanks Aunez & Alessandro

2) but the object must be drawn at least once, how can you do that on your desktop.

3) would compression have any effect on client/server environment.

Re: QVW Performance

juleshartley — Tue, 18 Feb 2014 16:53:39 GMT

There are various tools for assessing the 'load' of objects - the one that I am most familiar with is called 'QVW Optimizer' - see attached.

You point it at the .mem file for a particular app (having tried to perform as many operations as possible within the app).

Also there are various posts on improving performance.

Re: QVW Performance

userid128223 — Tue, 18 Feb 2014 17:10:14 GMT

I think the issue on my qvw is more to do with CPU time usage or calculation performance compare to memory issue. The application loads ok, however when user interacts, it goes into loop for minutes before it releases itself and goes futher.

Is there a tool that shows performance time during user interaction with charts or tables.

Re: QVW Performance

maxgro — Tue, 18 Feb 2014 17:47:44 GMT

here for memory stats

http://community.qlik.com/blogs/qlikviewdesignblog/2013/01/28/memory-statistics

but at the beginning I would look, if possbile at task manager (CPU, memory) or similar tools to have an initial idea about the cause of the problem (memory, cpu)

than you can start your optimization; you can find a lot of post here, for example

Re: Qlikview Best practices

Re: QVW Performance

Tue, 18 Feb 2014 18:09:57 GMT

Verify if your queries aren't returning any blob type field.