Testing User-Defined Functions

After UDF external code has been coded, compiled and linked, and the corresponding SQL functions and stored procedures have been defined, the UDFs are ready to be tested.

The reliability required by a database is extremely high. UDFs running within a database environment must maintain this high level of reliability. With the first implementation of the UDF API, UDFs run within the SAP Sybase IQ server. If a UDF aborts prematurely or unexpectedly, the SAP Sybase IQ server may abort. Ensure via thorough testing in a development or test environment, that UDFs do not terminate prematurely or abort unexpectedly under any circumstances.

• Enabling and Disabling User-Defined Functions
  Use the inmemory_external_procedure security feature to enable or disable the server's ability to make use of high performance in-process UDFs.
• Initially Executing a User-Defined Function
  To ensure the safest environment possible, install and invoke UDFs from a read-only server node in a multiplex installation.
• Controlling Error Checking and Call Tracing
  The external_UDF_execution_mode option controls the amount of error checking and call tracing that is performed when statements involving v3 and v4 external user-defined functions are evaluated.
• Viewing SAP Sybase IQ Log Files
  SAP Sybase IQ provides extensive logging and tracing capabilities. UDFs should provide the same or better level of detailed logging, in the event of problems in the UDF code.
• Using Microsoft Visual Studio Debugger for User-Defined Functions
  Microsoft Visual Studio 2008 developers use Microsoft Visual Studio Debugger to step through the user-defined function code.