I am implementing a page consisting of 2 gridviews, one using data store with AJAX proxy and other using data store with proxy as "sessionStorage".

Think of an operation "Add all" from AJAX data store to sessionstorage data store:
When I am dealing with small amount of data (100 or 500 or 1000 records with 15 columns, data size <500KB, data store operations such as "add" and "sync" operations take around one second or less than 1 second.

However when I am dealing with large amount of data (>=5000 records with 15 columns, data size >= 1.2MB, backend API call is returning within 1 sec, however store "add" is taking around 7 seconds and "sync" is taking around 17-18 seconds. That's a lot of time and unacceptable for our Product.

Based on my previous experience with data store, I am already using suspendEvents and data operations in local variables so that "add" and "sync" is called only with the final data and subsequent events are resumed ONLY after add and sync operations are done.

Did anyone face similar problems?

I would really appreciate if you have any suggestions.