Define a user-defined VP

You define a new virtual-processor class in the onconfig file with the VPCLASS configuration parameter.

The num option specifies the number of virtual processors in a user-defined VP class that the database server starts during its initialization. The class name is not case sensitive, but it must have fewer than 128 characters. If your DataBlade uses a prefix, such as USR, begin the names of any user-defined VPs with this prefix.

HCL Informix® supports the following types of user-defined VP classes for execution of an ill-behaved C UDR.

Type of user-defined VP class	VPCLASS option
Yielding user-defined VP	None (default type of user-defined VP class)
Nonyielding user-defined VP	noyield
Single-instance user-defined VP (yielding or nonyielding)	num=1

Important: When you edit the onconfig file to create a virtual-processor class, you must add a VPCLASS parameter and remove the SINGLE_CPU_VP parameter. For more information about the onconfig file, see the HCL Informix Administrator's Reference.

After you add or modify the VPCLASS configuration parameter, restart the database server with the oninit utility (or its equivalent). For more information about how to restart the database server, see your HCL Informix Administrator's Guide. You can add or drop user-defined virtual processors while the database server is online. For more information, see Add and drop VPs.

When you use a class of user-defined virtual processors to run a C UDR, you must ensure that the name of the VP is the same in both of the following locations:

In the VPCLASS parameter in the onconfig file, which defines the VP class
In the CLASS routine modifier of the CREATE FUNCTION or CREATE PROCEDURE statement, which registers the C UDR in the database

For more information, see Assign a C UDR to a user-defined VP class.