I'm evaluating new GXT 1.1 and many things have improved over previos versions, so congratulations to darell for excelent work.
Grid seems to perform quite fast even rendering quite large datasets. While testing this i have noticed that grouping grid performance rapidly deteriorates when used with large dataset.
I have a grid with two columns + grouping. When I put ~100 records in 6 groups it works very fast. When I put ~1000 records in the same groups it does not finish rendering in an hour (tested in firefox and chrome).
I'm sure there is always room to optimize code, but there will be a limit whereby this kind of set grouping should be performed by a server - expecting a client (remembering the web can be a kiosk, phone or low powered notebook) to process large amounts of data is not reasonable.
I'm not saying group 1,000 records is a big task, just that you probably need to consider if the design is right... perhaps the better approach would be to perform remote grouping (which is what I believe is still to come) where the grouping is done server side
your argument about ui design is valid. In this case user needs to have fast access to this whole data set. Scrolling and picking through 1000 items is no easy task, but using filtering and sorting makes it a breeze. There are other options/workarounds, wether requesting data from the server in smaller chunks, or displaying partial data in the grid, or using some other kind of user interface.
The concern I have, and maybe have not articulated clearly, is that performance drop is much too steep going from 100 to 1000 items.