In an ATG Commerce application, the product catalog is probably the single most important repository to size correctly. Based on the number of categories, products and SKUs you plan to maintain in your database, try to make sure the caches are large enough to hold your entire catalog, or at least the most frequently used portions of the catalog. It may not seem feasible to cache the entire catalog; however, experience has shown that it is perfectly manageable to cache a catalog consisting of 2,000 categories 10,000 products and 100,000 SKUs.
Set the caches in the OrderRepository based on your expected concurrent session count and the number of orders, items, and shipping groups you expect to have. Assuming you want to support 500 concurrent sessions, you might set the orders item cache at from 500 to 700. Assuming your customers will average of 3 commerce items per order, you might set the set the commerce item descriptor cache to 1500. Assuming you will have an average of 2 shipping groups per order, you might set the shippingGroup item descriptor cache to 1000 and so on for each item-descriptor defined.
