存储和更新Flex AdvancedDataGrid的分层数据的最有效方法是什么？

I have a Flex application that has an AdvancedDataGrid that displays hierarchical data in a tree. I'm currently storing this data in XML and it's being updated about every second. This was working well for a while, but the amount of data I have to store and update has increased lately and it's slowing down the application to the point that it's becoming unusable and crashing frequently.I have a Flex application that has an AdvancedD