Limit Number of Columns in a View Table

Performance impact: Variable

The number of columns projected in the view SelectList can impact performance. As the number of columns in the select list grows, the time to prepare operations on detail tables increases. In addition, the time to run operations on the view detail tables also increases. Do not select values or expressions that are not needed.

The optimizer considers the use of temporary indexes when preparing operations on detail tables of views. This can significantly slow down prepare time, depending upon the operation and the view. If prepare time seems slow, consider using ttOptSetFlag to turn off temporary range indexes and temporary hash scans.