Data Storage

[#1]

Hi,

I would like to know the difference by loading the data directly in to RAM. Loading the data in to QVD and then using the QVD as the data source.

A. I am creating the QVW file by directly connecting to the database .So the data will be stored in the RAM. And when ever i am accessing the QVW file the stored data will be there for the Analysis. No database connectivity establishment is required to access the already stored data.

B. if i am creating a QVW file with QVD as the datasource. It will be stored in RAM .So no need to connect to QVD file since it will in RAM. It means the data will be there as the QVD file in the Server as well the data will in the RAM.

Please correct me if the above understanding is wrong. If it is correct. Is it possible to remove the data stored in RAM of the QVW file which has the QVD as the datasource when the QVW file is not accessed.When ever the QVW file with datasource as QVD is accessed should connect to QVD file and store the data in RAM for analyzing.

[#2 · Accepted solution]

When you load the data, it ends up in RAM whether you directly connect to the database or use a QVD. QVDs can be useful as they can be used in multiple documents and be reloaded multiple times without going back to the database.

You can remove all the data from the file and therefore from RAM by choosing: File>Reduce Date>Remove All Values. This will decrease the file size, but in order for the document to be of any use, the user would have to do a Reload to get the data back.

You can also use DROP TABLE TableName; in the script to remove a table from memory.

To answer your question in the last paragraph, yes. Reduce Data to Remove All Values and Save. Then when the document is open, create a macro to reload the document (ActiveDocument.Reload).

[#3]

Thanks for your response Miller.

I have one more Query when i am loading the data , QVW file size is getting increased. What actually the QVW file contains. Also how the differentiation is as made as when i am opening the QVW file the related data is pulled from RAM.

[#4]

The QVW stores your layout objects and data. As you add more layout objects (charts, list boxes, etc) the file should increase slightly. Data will probably represent the majority of your QVW file size.

I'm not sure I understand the last question. When you open a QVW that contains data, I believe the data is immediately placed into RAM. If you have Reduced the data or if you didn't save the app with data in it, then no data will be loaded into RAM until you reload.