The versatility of Teradata Database is based on virtual processors (vprocs) that eliminate dependency on specialized physical processors. Vprocs are a set of software processes that run on a node under Teradata Parallel Database Extensions (PDE) within the multitasking environment of the operating system.
The following table contains information about the different types of vprocs:
| Vproc Type | Description |
|---|---|
| AMP | Access module processors perform database functions, such as executing database queries. Each AMP owns a portion of the overall database storage. |
| GTW | Gateway vprocs provide a socket interface to Teradata Database. |
| Node | The node vproc handles PDE and operating system functions not directly related to AMP and PE work. Node vprocs cannot be externally manipulated, and do not appear in the output of the Vproc Manager utility. |
| PE | Parsing engines perform session control, query parsing, security validation, query optimization, and query dispatch. |
| RSG | Relay Services Gateway provides a socket interface for communication with Teradata Data Stream Architecture (DSA). |
| TVS | Manages Teradata Database storage. AMPs acquire their portions of database storage through the TVS vproc. |
A single system can support a maximum of 16,384 vprocs. The maximum number of vprocs per node can be as high as 128, but is typically between 6 and 12.
Each vproc is a separate, independent copy of the processor software, isolated from other vprocs, but sharing some of the physical resources of the node, such as memory and CPUs. Multiple vprocs can run on an SMP platform or a node.
Vprocs and the tasks running under them communicate using unique-address messaging, as if they were physically isolated from one another. This message communication is done using the Boardless BYNET Driver software on single-node platforms or BYNET hardware and BYNET Driver software on multinode platforms.