Determining if a UDx signature has changed

You need to be careful when making changes to UDx libraries that contain functions you have already deployed in your Vertica database. When you deploy a new version of your UDx library, Vertica does not ensure that the signatures of the functions that are defined in the library match the signature of the function that is already defined in the Vertica catalog. If you have changed the signature of a UDx in the library then update the library in the Vertica database, calls to the altered UDx will produce errors.

Making any of the following changes to a UDx alters its signature:

• Changing the number of arguments accepted or the data type of any argument accepted by your function (not including polymorphic functions).

• Changing the number or data types of any return values or output columns.

• Changing the name of the factory class that Vertica uses to create an instance of your function code.

• Changing the null handling or volatility behavior of your function.

• Removed the function's factory class from the library completely.

The following changes do not alter the signature of your function, and do not require you to drop the function before updating the library:

• Changing the number or type of arguments handled by a polymorphic function. Vertica does not process the arguments the user passes to a polymorphic function.

• Changing the name, data type, or number of parameters accepted by your function. The parameters your function accepts are not determined by the function signature. Instead, Vertica passes all of the parameters the user included in the function call, and your function processes them at runtime. See UDx parameters for more information about parameters.

• Changing any of the internal processing performed by your function.

• Adding new UDxs to the library.

After you drop any functions whose signatures have changed, you load the new library file, then re-create your altered functions. If you have not made any changes to the signature of your UDxs, you can just update the library file in your Vertica database without having to drop or alter your function definitions. As long as the UDx definitions in the Vertica catalog match the signatures of the functions in your library, function calls will work transparently after you have updated the library. See Deploying a new version of your UDx library.