@PublicEvolving public interface SpecializedFunction extends FunctionDefinition
FunctionDefinitionthat can provide a runtime implementation (i.e. the function's body) that is specialized for the given call and session.
The planner tries to defer the specialization until shortly before code generation, where the
information given by a
FunctionDefinition is not enough anymore and a subclass of
UserDefinedFunction is required for runtime.
This interface is useful when the runtime code should know about information that is only available after planning (e.g. local session time zone or precision/scale of decimal return type).
UserDefinedFunction that is registered in the API is implicitly specialized but can
also implement this interface to reconfigure itself before runtime.
Note: This interface is a rather low level kind of function but useful for advanced users.
|Modifier and Type||Interface and Description|
Provides call and session information for the specialized function.
|Modifier and Type||Method and Description|
Provides a runtime implementation that is specialized for the given call and session.
UserDefinedFunction specialize(SpecializedFunction.SpecializedContext context)
The method must return an instance of
UserDefinedFunction or throw a
TableException if the given call is not supported. The returned instance must have the same
FunctionDefinition semantics but can have a different
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