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Is there any way to know the % of data compressed by QV

Hi Forums,

I know that the QlikView compress the data about from 20% - 90%.

But is there any way to know exactly by how much % the data is compresse by QV of given appl?.

Advance Thanks

SD

Labels (2)
6 Replies
hrlinder
Honored Contributor

Re: Is there any way to know the % of data compressed by QV

I donot think that there is a formula!

my own experience is, that it depends on your data.

I had once a datamodel which took about 500 MB RAM.

I only changed the sort of the maintable (order by) and

the filesize was reduced to 300 MB!!!


That behaviour I noticed more than once!

MVP
MVP

Re: Is there any way to know the % of data compressed by QV

Hi shan,

you could store the same data twice as txt file and as qvd and compare the file size.

- Ralf

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Re: Is there any way to know the % of data compressed by QV

Hi Ralf/Rudolf,

Thanks for response and showing the work around.

But, It is my personal question that, Do u don't think that there should be some tool/mechanism to

know the exact % of data compression done by QV.  So, that we can give the Proper RAM Sizing.

Thanks

SD

MVP
MVP

Re: Is there any way to know the % of data compressed by QV

Qlik professional services will help you with server sizing. As we went thru this in the past we used a complex Excel sheet from Qlik to calc memory size. You can also take a look here: http://community.qlik.com/blogs/qlikviewdesignblog/2013/01/28/memory-statistics#comment-8362

hrlinder
Honored Contributor

Re: Is there any way to know the % of data compressed by QV

sure it would be nice to know the exact Ratio.

I once had to give an estimate for a new server

but as i wrote, the filesize can differ huge

In Memory there is no difference. so it is only

the way QV stores the data. My assumption is

that QV compares each row and stores only

changed values (that's what I changed the sorting).

BUT MY ASSUMPTION

And again to your question: Yes, it would be good,

Operation Needs to know how much space they should

provide!

Maybe with "medium" compression there might be a better

formula?

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Re: Is there any way to know the % of data compressed by QV