topic Re: Memory of Hidden objects in server in QlikView

Memory of Hidden objects in server

sundarakumar — Thu, 11 Sep 2014 09:38:52 GMT

Hi All,

Will a Hidden object consume server memory while the user access the particular sheet, where this hidden object is present? or is it like a minimised object.

This hidden object a Pivot table which will be shown only on a filter selection. The hide condition is set in layout tab.

Can someone pls help with this?

-Sundar

Re: Memory of Hidden objects in server

sundarakumar — Fri, 12 Sep 2014 04:45:17 GMT

Hi All,

Any thoughts please......

Re: Memory of Hidden objects in server

jagan — Fri, 12 Sep 2014 05:29:03 GMT

Hi,

Hidden objects won't consume memory, you can test like this.

Step 1: For unhidden object

Sheet Properties -> Objects-> Check the corresponding Object Memory value.

Step 2:

Now hide the object by using Chart Properties -> Layout -> Show - Conditional = 0

Now check memory size

Sheet Properties -> Objects-> Check the corresponding Object Memory value.

you will get memory size as 0.

Hope this helps you.

Regards,

Jagan.

Re: Memory of Hidden objects in server

sundarakumar — Fri, 12 Sep 2014 12:39:20 GMT

is it calctime or memory?

Re: Memory of Hidden objects in server

jagan — Mon, 15 Sep 2014 01:31:22 GMT

Hi,

Calctime is for calculation time and Memory is for memory occupied, in your case it is Memory.

Regards,

Jagan.

Re: Memory of Hidden objects in server

sundarakumar — Mon, 15 Sep 2014 05:40:20 GMT

Hi jagan,

I tried out what u have suggested in Step1 and step2 above, Looks like there is no change in memory for a object when it is hidded or shown. Only the calctime changes to zero when i hide the object. Does that mean hidden object takes ram? Pls suggest..

-Sundar

Re: Memory of Hidden objects in server

Anonymous — Mon, 15 Sep 2014 05:45:20 GMT

No , it will also not take any memory while hidden.....

Re: Memory of Hidden objects in server

jonathandienst — Mon, 15 Sep 2014 05:52:46 GMT

A hidden object may consume memory. If it has been un-hidden at some point, then it will have been calculated, and the calculation results would be stored in cache memory. I don't think that the cache would be cleared if the object is hidden again using an action. Perhaps someone from Qlik would like to add to this discussion.

HTH

Re: Memory of Hidden objects in server

sundarakumar — Mon, 15 Sep 2014 05:53:58 GMT

Nitin,

I have a pivot table which will return me millions of rows by default. In layout condition I have given a condition to make to chart pop up only if a shop is selected. with a single shop selected it would be only hundred rows in pivot table. My Dashboard porformance is not good. Do u think this hidden pivot table takes ram and makes the dashboard perform slow. Am aware of "calculation condition" in general tab. But i have not give any condition to it. Will a hidden object take memory for calculations on user selections? what if the user selects a country? will my pivot table which is hidded consume memory?

Pelase advise..

-Sundar

Re: Memory of Hidden objects in server

Anonymous — Mon, 15 Sep 2014 06:06:51 GMT

Until the object is hidden (Layout>Show>Conditional),

It do not take RAM .

The abject will be calculated only when it is shown......

Re: Memory of Hidden objects in server

jonathandienst — Mon, 15 Sep 2014 06:24:32 GMT

I doubt that memory consumption is causing poor performance in your dashboard, unless your server has too little RAM for your application.

I would look at the structure of your model -

Is your data model a well formed star schema, or is it more complicated?

Are the tables associated using a single key, or a simple composite key?

Are there a lot of rows in tables that are not associated with any other tables?

And the expressions -

Do you use calculated dimensions (especially if these could be replaced by derived fields during load)?

Do you use sum(if()) structures or similar structures requiring massive joins

Are your expressions very complex (Pick(Match()) or deeply nested If() statements, many terms...

Any of these can cause performance issues, especially when the fact table(s) contain millions of rows.

HTH

Jonathan

Re: Memory of Hidden objects in server

sundarakumar — Mon, 15 Sep 2014 07:17:56 GMT

Hi Jonathan,

Thanks for the suggestions.

Model Structure.

1. it is kind of a fact constellation where I Have 2 main fact tables linked to each other. The diemnsions get linked to either of the facts. There is a main dimension table which gets linked to the facts with the key that is used to link the facts together, this creates a node of 3 tables (2 fact and 1 diemnsion)

2. Association is with a composite key which has four fields concatenated. it is numeric

3. there are only few island tables, they have less row count.

Expression:

1. there is no calcuated dimension used.

2. no if statements

3. mostly sum() and only(). we use set analysis and if in some cases. but no a very complicated expression

The most important thing is fact table has very less number of columns not even a millon.

Server RAM - 16gb

application size - 6 mb

This is y am worried abt the performance. This should be good. do u think the data model is the issue out there?

or the hidded pivot?

Please advise...

-Sundar

Re: Memory of Hidden objects in server

jonathandienst — Thu, 18 Sep 2014 10:06:18 GMT

Sounds OK, except for the island tables. Are these used in the objects that perform poorly. When there is no association, QV has to perform a cartesian join to perform calculations which use fields from the main fact and the island table. This can cause a large spike in memory and affect performance badly.

Are the key field values unique in the dimension and in the 2 fact tables?

The model size on disk is not a reflection of how much RAM it requires. The compressed qvw expands on loading (possibly to between 1 and 2GB in your case), and will increase further if joins are necessary to perform the calculations. Check using task manager.

HTH

Jonathan