If a UNION ALL view has a very large number of arms or a very large number of columns in each arm, then an enhancement to the optimizer in this release significantly improves query performance when there are many unused view columns.
An enhancement to the optimizer in estimating the number of distinct values improves the performance of queries with a UNION ALL view on unscaled integer columns.
In this release, the GROUP BY over a UNION ALL view performance enhancement can be applied to queries with more than one view column in the argument of an aggregate function.
For more information on queries that reference UNION ALL views, see Chapter 4, “Managing System Resources” in the Sybase IQ Performance and Tuning Guide.
