FetchAs > WorkArea

Each time a map is executed, information about the data and map is kept in a workspace and is used as the input data is validated and the output data is built. This workspace information can either be stored in files or written to memory.

A card's WorkArea setting specifies whether to reuse that work area on subsequent executions of the same map. If you are repeatedly going to run the same map using the same input data more than once, setting the WorkArea card setting value to Reuse increases the speed of map execution because data validation for this input is not repeated. There are guidelines for reusing work areas.

Reuse the work area. After a map runs for the first time, the work area that is created for the input card is not deleted. Then, on subsequent executions of the same map, the data for this input card is not validated, and the work area information for the card is retrieved from the existing work area.
Do not reuse the work area. The input card's WorkArea is created for each map execution.