FILTER

FILTER

Operator name: FILTER

Represents: The application of residual predicates so that data is filtered based on the criteria supplied by the predicates.

Performance suggestions:

• Ensure that you have used predicates that retrieve only the data you need. For example, ensure that the selectivity value for the predicates represents the portion of the table that you want returned.

• Ensure that the optimization class is at least 3 so that the optimizer uses a join instead of a subquery. If this is not possible, try rewriting the SQL query by hand to eliminate the subquery. For an example, see the section on query rewrites by the SQL compiler in the Administration Guide.