topic Re: QVD Optimization in QlikView

QVD Optimization

Tue, 20 May 2014 10:20:58 GMT

Hi QV,

I have 25 tables in the database, and I simply created qvd's for all the tables.

Now I want to optimize these QVD files. Can anyone suggest me how to optimize the qvd files, and how would I know that weather the qvd's are optimized or not.

Thanks,

Ananth

Re: QVD Optimization

alexandros17 — Tue, 20 May 2014 10:26:58 GMT

Qvd is said to be optimized if when you reload it you avoid where conditions or if clause on fields ...

Re: QVD Optimization

ThornOfCrowns — Tue, 20 May 2014 10:30:05 GMT

Generally, adding fields or anything that causes a field value to be examined will force an unoptimized load.

You will see in the loading window if the load is optimized or not.

Re: QVD Optimization

jagannalla — Tue, 20 May 2014 10:31:00 GMT

Hi,

Load the qvd files in without any transformations( i.e. expressions). While loading the qvd file in script you should not include any calculation part or transformation in script. If you include it can be treated as UnOptimized load.

Cheers!!

Jagan

Re: QVD Optimization

Tue, 20 May 2014 10:37:18 GMT

Thanks to all for your valuable responses.

So all of you meant to say that, there should be no filtering conditions in the script. Isn't it?

Re: QVD Optimization

Tue, 20 May 2014 10:38:34 GMT

Hi,

When you load a QVD optimized, you can read it:

Re: QVD Optimization

Colin-Albert — Tue, 20 May 2014 10:40:23 GMT

You can have a single Where Exists clause and the reload will still be optimised.

That said reloading from QVD will still be faster compared to accessing the source database. Check the progress window during the load to see if the loads from QVD are marked as optimised.

Re: QVD Optimization

Tue, 20 May 2014 10:40:58 GMT

Thanks a lot Augustin, it was very much helpful.

Re: QVD Optimization

ThornOfCrowns — Tue, 20 May 2014 10:43:35 GMT

Yes, that's pretty much it.

Loading your data from a QVD then working on the data afterwards to ensure an optimized load is very much a trade off as to load speed versus RAM footprint. If you have a lot of required data in your QVD, you may want to make that trade or you may want to have an unoptimized load by using a WHERE clause, etc.