How to project how much memory do I need to open a qvw?

[#1]

Hi

How do I know how much memory from the server takes to open a qvd or qvw? I realize that I'm a little bit tight of resources and I want to make a projection.

Thanks

[sibrulotte]

A consultant showed me this, and If I'm not mistaking, I think it was 1.4 times the amount of ROM the file took, times the number of simultaneous users.

Let me check the web.

[paul_scotchford]

Add around 10% memory consumption for every instance of the original document opened.

What is you server config ? What is the largest QVW that you have ?

[maxgro]

Hi Pablo

you can find some help here

http://community.qlik.com/message/393976#393976

There is also the Qlikview Server Load Simulator.qvw to download at the sameplace

Regards

[Colin-Albert]

Memory is not only consumed when opening a QVW, but is also used to cache expressions as users make selections within the app. If the server has free memory then the caching will improve performance as calculations can be retrieved from the cache rather than being recalculated. When memory resources are low, typically 70%, QlikView implements memory management to drop old cached expressions, this is normal. When the upper limit is reached (90%) then the memory management becomes more aggressive, which can impact on performance. So it is not simply a case of having sufficient memory to open all apps on the server.

[stevedark · Accepted solution]

Hi there,

The server will not directly load a QVD (though you will most likely have QVWs the create or consume these on the server).  The size of a QVW on disk gives a good indication of how much memory it will take when loaded by the server.  As well as a copy of the full QVW in memory each user connected to that document via the server will have their own cache - this is typically about 10% of the size of the document per user.  As Colin points out, what the user is doing in the document (eg. what charts they are viewing and what selections they are making) will have a bearing on this.

QlikView Server is very good at managing it's memory - so it will just load items when it needs them and clears things down once no longer needed.

Hope that helps.

Steve

[Peter_Cammaert]

A good (and fairly recent) explanation of memory and cpu usage by the QlikView Server is found in the QlikView Resource Library at www.qlik.com/us/explore/resources. The Technical Briefs section contains this useful document: QlikView Architecture And System Resource Usage  In your case especially pages 6-9 provide valuable info

Best,

Peter

[Anonymous]

Pablo

You say that you are 'a little bit tight of resources', what symptoms are you experiencing that brings you to that conclusion ?

Best Regards,     Bill

[rwunderlich]

Previous comments and the referenced technical brief suggest that the qvw size on disk can be used to estimate the RAM requirement. But it's guesswork (tech brief suggests 2x to 10x) if the qvw is compressed (default). There are three methods I can suggest to get accurate  RAM requirements of the initial document open.

1. Save the QVW uncompressed (Document Properties, General, Compression, None). Then the QVW size on disk = RAM for open.

2. Generate memory statistics for the file (Document Properties, General, Memory Statistics button). Process the statistics with a QV app like QV Optimizer.

3. Use Document Analyzer (Downloads - Rob Wunderlich Qlikview Consulting) . The "Memory" sheet as discussed here Qlikview Notes: Identifying Unused Fields With DocumentAnalyzer will show how much RAM is required. It may also identify opportunities for RAM savings by dropping unused fields.

More about memory and disk compression here.

Qlikview Notes: Document Compression

-Rob

http://masterssummit.com

http://robwunderlich.com

[#10]

Thanks Simon