Hi Bheemeswar,

Basically the data pages will be stored in the clipboard memory whenever the data page is referred it creates an instance of data page in the clipboard if it doesn't exist.

When the system references a data page, the data page either creates an instance of itself on the clipboard and loads the required data in it for the system to use, or responds to the reference with an existing instance of itself. 

The above information is explained in Pega 7 management of data pages

Hope this might help you.

Regards

Mahesh