17.10 - Multi-Session Management - Call-Level Interface Version 2

Teradata® Call-Level Interface Version 2 Reference for Workstation-Attached Systems

Product
Call-Level Interface Version 2
Release Number
17.10
Release Date
October 2021
Content Type
Programming Reference
Publication ID
B035-2418-061K
Language
English (United States)

An application can achieve true parallel request processing by using more than one database session. The application can then dispatch several requests simultaneously, one on each session.

How It Works

Each concurrent request can be identified to CLI by using the id of the session with which it is associated (that is, the value in Output Session Id from a call to DBCHCL for the Connect function) and its own id (that is, the value in Output Request Id from a call to DBCHCL for the Connect, Initiate Request, or Run Startup function).

Using Tokens

The application may also supply a token for each request when it is initiated. That token is returned by the DBCHWAT routine when a request’s response arrives.

An application may have requests pending on several sessions simultaneously. One way for the application program to wait is to call an asynchronous wait using DBCHWAT. The wait ends when any outstanding request completes.