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Data Island Expression

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"

Guide​

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 once: 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)