A virtual-processor class

A virtual process is a process that the database server uses to execute queries and perform other tasks, such as disk I/O and network management. A small number of virtual processors (VPs) can carry out tasks on behalf of many client applications because the database server breaks the client-application requests into pieces called threads. The VP can schedule the individual threads internally for processing. Therefore, VPs are multithreaded processes because they can run multiple concurrent threads.

The database server implements its own threads to schedule client-application requests. These threads are not the same as operating-system threads, which multithreaded operating systems provide.

Virtual processors are grouped into virtual-processor classes, or VP classes. All VPs in a particular VP class handle the same type of processing. The database server supports the following VP classes.

CPU: Central processing (the primary VP class, which controls client-application requests)
AIO: Asynchronous disk I/O
SHM: Shared-memory network communication
JVP: Special VP class for execution of Java™ UDRs
User-defined: Special VP classes for additional types of processing

For general information about virtual processors, see the HCL OneDB™ Administrator's Guide.