IBM OS Affinity lifetimes, CICS programming techniques for transaction affinity, Userid, System

Userid

A group of transactions where all instances of the transactions that are

initiated from a terminal and executed on behalf of the same userid must

execute in the same target region for the lifetime of the affinity. The affinity

lifetime for userid relations can be pseudoconversation, signon, system, or

permanent.

Affinity lifetimes

The affinity lifetime determines when the affinity is ended.An affinity lifetime can be

classi®ed as one of:

System

The affinity lasts for as long as the target region exists, and ends whenever

the target region terminates (at a normal, immediate, or abnormal

termination). (The resource shared by transactions that take part in the

affinity is not recoverable across CICS restarts.)

Permanent

The affinity extends across all CICS restarts. (The resource shared by

transactions that take part in the affinity is recoverable across CICS

restarts.) This is the most restrictive of all the inter-transaction affinities.

Process

The affinity exists until the process completes.

Activity

The affinity exists until the activity completes.

Pseudoconversation

The (LUname or userid) affinity lasts for the whole pseudoconversation, and

ends when the pseudoconversation ends at the terminal.

Logon

The (LUname) affinity lasts for as long as the terminal remains logged on to

CICS, and ends when the terminal logs off.

Signon

The (userid) affinity lasts for as long as the user is signed on, and ends

when the user signs off.

Notes:

1.For userid affinities, the pseudoconversation and signon lifetimes are possible only in those situations where one user per userid is permitted. Such lifetimes are meaningless if multiple users are permitted to be signed on with the same userid at the same time (at different terminals).

2.If an affinity is both userid and LUname (that is, all instances of all transactions in the group were initiated from the same terminal and by the same userid), LUname takes precedence.

CICS programming techniques for transaction affinity

Associated with transaction affinity, there are three broad categories of CICS programming techniques:

vSafe programming techniques

vUnsafe programming techniques

vSuspect programming techniques

Chapter 1. Introducing transaction affinities 5