| Building and Deploying Flex 2 Applications > Building and Deploying Overview > Optimizing Flex Applications > Improving client-side performance > Application coding > Using large data sets | |||
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This section describes how to minimize overhead when working with large data sets.
When you use a DataService class to get your remote data, you might have a collection that does not initially load all of its data on the client. You can prevent large amounts of data from traveling over the network and slowing down your application while that data is processed using paging. The data that you get incrementally is referred to as paged data, and the data that has not yet been received is pending data.
The paging features of the DataService class include:
For more information, see Using Data Providers and Collections in Flex 2 Developer's Guide.
One issue when using a DataGrid control with large data sets is that it may be slow to scroll when using the scrollbar. When the DataGrid displays newly visible data, it calls the getItemAt() method on the data provider.
The default behavior of a DataGrid is to continuously update data when the user is scrolling through it. As a result, performance can degrade if you just simply scroll through the data on a DataGrid because the DataGrid is continuously calling the getItemAt() method. This can be a computationally expensive method to call.
You can disable this live scrolling so that the view is only updated when the scrolling stops by setting the liveScrolling property to false.
The default value of the liveScrolling property is true. All subclasses of ScrollControlBase, including TextArea, HorizontalList, TileList, and DataGrid, have this property.
Flex 2
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