The expression "xxx" uses a Field from an island table. Improper use of island fields may lead to performance problems. The field(s) are: "yyy"
Examine the performance of any chart using a data island expression. If a data island field it used with other dimensions, a temporary table of all possible combinations must be generated during calculation. To avoid this temp table generation, consider one of the following alternatives.
•For a single value island field, such as a currency selection, replace the field reference with a $() expression. The $() expression is calculated only one.
- Sum(Sales) / $(=Only(CurrencyRate))
•Another good option is to replace the field reference with a variable calculation.
- Create a variable: Set vCurrencyRate = =Only(CurrencyRate); // Note the extra "="
- Use the variable in the expression: Sum(Sales) / $(vCurrencyRate)