Check the startDate, endDate, beginUsable, and endUsable dates of all promotions to prevent a promotion from taking effect before you are ready for it.

Note: When setting dates for a promotion, be aware that a number of factors can cause the promotion to be unusable for a number of minutes after it is set to be active engine (for global promotions) or the PricingModelHolder (for both global and non-global promotions).

Because it can be resource intensive to collect a user’s list of promotions, or pricing models, the session-scoped UserPricingModels component (class atg.commerce.pricing.PricingModelHolder) stores them in a session cache. When a session starts for a user, UserPricingModels queries each pricing engine for the customer’s promotions. PricingModelHolder is schedulable, and can also be configured to periodically update the promotions cache.

These promotions include both the promotions in the user’s activePromotions profile property and the list of global promotions. To retrieve the list of global promotions, the pricing engine uses its globalPromotionsQuery property to query the Promotions repository for all promotions where the global property is set to true, and it does so every x minutes as defined by the schedule specified in its updateSchedule property. Once collected, the pricing models in UserPricingModels are then used for all pricing operations during the user’s session.

Consequently, if a user’s session is created after you have added a new global promotion but before the next scheduled job to update the pricing engine’s list of global promotions, the user will not receive the new global promotion. You can prevent this situation by manually calling the pricingEngine.
loadGlobalPromotions method when you add the new global promotion. Additionally, if a user’s session was created before you added a new promotion (either targeted or global), that user will never receive the new promotion. This is because the user’s list of pricing models has already been collected and stored in the user’s UserPricingModels. To prevent this situation, manually call the pricingModelHolder.initalizePromotions method when you add any new promotion (targeted or global). The initializePromotions method generates a new list of pricing models to store in the user’s UserPricingModels. (Note that the pricingModelHolder.initializePromotions method should be called after the pricingEngine.loadGlobalPromotions method in order to collect all new global promotions.)

For more information on the PricingModelHolder class, see the PricingModelHolder section. For more information on the pricing engine APIs, see the Core Commerce Pricing Engines chapter.

When creating promotions, evaluate the wording of the discount rule carefully to make sure that only the intended products receive the promotion. Be as specific as possible when creating rules. For example, if a particular brand is on sale, specify the brand in the rule rather than relying on an attribute of the brand that you might think is unique.

Use caution when creating “infinite use” promotions, which a customer can use an infinite number of times during a specified time period. Be certain the beginUsable and endUsable dates are set correctly.

When creating promotions that use fractional quantities to qualify or target commerce items, ensure that the commerce item allows fractional quantities. For example, it is possible to create a promotion that gives %50 off of half a shirt, but it is suggested that you not do so.