Modifier Descriptions

The following sections describe the modifiers that you can use to help the database server optimally execute a UDR.

CLASS
COSTFUNC (C)
Use the COSTFUNC modifier to specify the cost of a UDR. The cost of the UDR is an estimate of the time required to execute it.
HANDLESNULLS
INTERNAL
ITERATOR
NEGATOR
PARALLELIZABLE
PERCALL_COST (C)
Use the PERCALL_COST modifier to specify the approximate CPU usage cost that a UDR incurs each time it executes.
SELCONST (C)
Use the SELCONST modifier to specify the selectivity of a UDR. The selectivity of the UDR is an estimate of the fraction of the rows that the query will select.
SELFUNC (C)
Use the SELFUNC modifier with a C UDR to name a companion user-defined function, called a selectivity function, to the current UDR. The selectivity function provides selectivity information about the current UDR to the optimizer.
STACK (C)
VARIANT and NOT VARIANT

Parent topic: Routine modifier