Fenced or unfenced considerations

 

When you create a user-defined function (UDF), consider whether to make the UDF an unfenced UDF.

By default, UDFs are created as fenced UDFs. Fenced indicates that the database should run the UDF in a separate thread. For complex UDFs, this separation is meaningful as it will avoid potential problems such as generating unique SQL cursor names. Not having to be concerned about resource conflicts is one reason to stick with the default and create the UDF as a fenced UDF. A UDF created with the NOT FENCED option indicates to the database that the user is requesting that the UDF can run within the same thread that initiated the UDF. Unfenced is a suggestion to the database, which can still decide to run the UDF in the same manner as a fenced UDF.

CREATE FUNCTION QGPL.FENCED (parameter1 INTEGER) 

RETURNS INTEGER LANGUAGE SQL

BEGIN RETURN parameter1 * 3;

END;


CREATE FUNCTION QGPL.UNFENCED1 (parameter1 INTEGER) 

RETURNS INTEGER LANGUAGE SQL NOT FENCED
-- Build the UDF to request faster execution via the NOT FENCED option BEGIN

RETURN parameter1 * 3;

END;

 

Parent topic:

Writing UDFs as external functions

 

Related reference

Threads considerations