The BUFFER prefix lets QlikView Script Engine create caches for individual data sources. This means that in a few particular cases (e.g. large database tables, or log files) most of the time you can avoid reloading from the slow original and take the data from the very fast QVD buffer. The prefix options allow you to specify when the scripting engine has to skip the buffer and take a peek at the original data source in order to avoid mismatches or ageing of data.
