In my previous article, Improving Bulk User Creation in AEM 200x, I discussed how we improved a process importing thousands of groups and users into Adobe Experience Manager. This drastic speedup enabled our project to pass the development tests and we looked good going into production. Unfortunately, as soon as we got access to the production user set, we ran into another performance trap. Our non-production data set had approximately 2,000 groups, while production had more than 4,000. Even worse, there were a factor fewer user <_-> group associations in non-production. The production data had nearly 100,000,000 user <_-> group associations, while non-production only had less than a tenth as many.