With Net.Data for OS/400, macro caching is enabled by default and is used to improve throughput and reduce CPU utilization. When macro caching is enabled, preprocessed macros are cached in memory when the macros are first invoked. These preprocessed versions are then available for reuse, thereby eliminating the costs associated with reading and the macros from HFS and processing them each time they are requested. The cached version of a macro is available to a requestor that has read permission for the file containing the macro.
The amount of memory that the preprocessed version of the macro uses is approximately twice the size of the macro file itself. You can control the amount of memory that will be used for the caching of macros by using the caching configuration variable. For more information on using this variable, see DTW_MACRO_CACHE_SIZE: Macro Cache Size Variable.