Once we have optimized our data model, we can turn our focus onto chart performance. There are a few different things that we can do to make sure that our expressions are optimal, and we can use the memory file extract to test them.

Some of the expressions will actually involve revisiting the data model. If we do, we will need to weigh up the cost of that performance with changes to memory, and so on.

It will be useful to begin with an explanation of how the QlikView calculation engine works.