Maplex Label Engine memory usage

Labeling can be a memory-intensive process, as the positions of hundreds or thousands of pieces of text are determined by the label engine. The Maplex Label Engine allocates memory on an as-needed basis during the labeling process. If necessary, the label engine will use all available physical memory during a labeling process. Due to performance reasons, no explicit paging to virtual memory is performed by the Maplex Label Engine during labeling. However, some paging may be performed by the operating system. A labeling process can exhaust physical memory, especially when labeling is being performed while converting labels to annotation. This typically has one of two results:

• Labels are placed with decreased quality.
• The labeling process ends with an out-of-memory error.

The amount of memory used depends on a number of items including the following:

• The number of features being labeled
• The extent of the map being labeled
• The number of trial positions generated based on the label placement properties

If you encounter issues with memory usage while labeling with the Maplex Label Engine, try reducing one of the parameters above. For instance, label a smaller extent of features if a larger extent does not complete labeling. Or when converting labels to annotation, only convert the labels within the displayed extent or use the Tiled Labels To Annotation tool to convert labels to annotation for layers in a map document based on a polygon index layer.