The ATG SQL repository offers a choice of cache modes. When you have only a single ATG instance installed, you can use the simple cache mode with no problems, since there is no chance of two servers using inconsistent copies of a repository item due to caching. However, when you deploy multiple ATG instances, you need to choose an appropriate cache mode for each item descriptor used by your application. See the ATG Repository Guide for more information.

In particular, if your sites are running more than one ATG server, it is highly recommended that you use locked mode caching for the individualScenario item descriptor. See the ATG Personalization Programming Guide for more information.

Remember that if you use locked mode caching, you must also enable lock manager components. See Enabling the Repository Cache Lock Managers in this chapter.