What is Activation Group?

Activation Groups on IBM i:

Activation group works like a Sub environment which allows sharing the open resources and/or overrides with across programs called in the Activation Group. 

Activation groups are one of important concepts on ILE on IBM i and makes it different from OPM in terms of how resources are shared with calling programs. 

E.g.:

We will consider a scenario of Batch Job which processes pending transactions in a Specific Application. 

Driver Program of Batch Job can create Overrides (OVRDBF) and/or Open Query (OPNQRYF) on a file with a set of conditions and calls multiple programs for processing different transactions. 

Considering the Overrides are created to share the resources across Activation Group (*ACTGRP), Result set of table (on top of OPNQRYF) would be made available to all the programs called in the specific activation group and avoids the need to perform override in every program.

When a program is created, we can choose on how the program needs to be run (in terms of Activation Group).
  • Default Activation Group
  • New Activation Group
  • Caller Activation Group
  • Named Activation Group
  • QILE/QILETS
We will see about each of these in detail.

Default Activation Group (DFTACTGRP):

This Keyword specifies whether program needs to run in the Default Activation Group of a Specific Activation Group.
  • When *YES is specified, Program will always run in the Default Activation Group. This option makes the program to run like OPM. This would also mean we cannot use BNDDIR or ACTGRP while creating the Program 
  • When *NO is specified, Program will be associated with the Activation Group mentioned in ACTGRP keyword. This is very useful in order to take the advantage of most of the ILE concepts. 
E.g.: DFTACTGRP keyword on CRTBNDRPG
CRTBNDRPG PGM(NEWPGM) SRCFILE(SRCLIB/QRPGLESRC) DFTACTGRP(*YES)

CRTBNDRPG PGM(NEWPGM) SRCFILE(SRCLIB/QRPGLESRC) DFTACTGRP(*NO) ACTGRP(*NEW)

New Activation Group (*NEW):

Specifying '*YES' on DFTACTGRP Keyword would allow the programmer to specify required Activation Group in ACTGRP parameter. 

'*NEW' would create the new activation group every time the Program is called. And, System would randomly create Activation group name and cannot be specified by programmer.

If the Program is called by two different users at the same time, Two new Activation Groups are created.

Caller Activation Group (*CALLER):

'*CALLER' on ACTGRP would make the program to run under the Activation Group determined by the Calling program. 

E.g.: If PGM2 is compiled with ACTGRP(*CALLER), PGM1 is compiled with ACTGRP(*NEW) and PGM2 is called from PGM1,

When PGM1 is called, System would create new Activation Group and when PGM2 is called, PGM2 will run under the same Activation Group (created by PGM1).

Named Activation Group:

Name of the Activation Group can be determined the Programmer as required by Application. 
CRTBNDRPG PGM(NEWPGM) SRCFILE(SRCLIB/QRPGLESRC) DFTACTGRP(*NO) ACTGRP(ACT1)
If the Application is to run under specific Activation group, Driver program for the program for the application can be compiled with specific Name in Activation Group and the calling programs can be compiled using ACTGRP(*CALLER)

QILE/QILETS:

QILE/QILETS are the Activation groups created by IBM. These can be used if there is no specific requirement for Activation group and to utilize the advantages of ILE concepts (as Default Activation Group makes the program to behave like OPM).

  • Q denotes this is Activation Group created by IBM.
  • ILE denotes to Integrated Language Environment.
  • TS denotes to Teraspace.

QILE/QILETS cannot be directly specified by the programmer. Storage Model (STGMDL) would determine if the program needs to compile with QILE or QILETS. Below are the possible options for Storage Model.
  • *SNGLVL - The program is created with single-level storage model.  When a single-level storage model program is activated and run, it is supplied single-level storage for automatic and static storage. A single-level storage program runs only in a single-level storage activation group.
  • *TERASPACE - The program is created with teraspace storage model.  When a teraspace storage model program is activated and run, it is supplied teraspace storage for automatic and static storage. teraspace storage program runs only in a teraspace storage activation group.
  • *INHERIT - The program is created with inherit storage model. When activated, Program adopts the storage model it is activated into. When this is selected, ACTGRP(*CALLER) must be selected.
If STGMDL(*TERASPACE) is specified, the program will be activated into the QILETS activation group when it is called. Otherwise this program will be activated into the QILE activation group when it is called.

CRTBNDRPG PGM(NEWPGM) SRCFILE(SRCLIB/QRPGLESRC) DFTACTGRP(*NO) 
ACTGRP(*STGMDL) STGMDL(*TERASPACE)

Comments

Post a Comment

Popular posts from this blog

What is the importance of User Open (USROPN) in RPGLE - IBM i

User Open (USROPN) USROPN (User Open) in RPGLE provides the flexibility for the programmer to open a file at a specific point in the program execution. In this post, let's explore what is the use of a USROPN and what is the importance of USROPN and how to use it with a simple example. What is the use of USROPN? By default, any file in the RPGLE (defined in F-Spec) opens as soon as the program execution is started and file is closed at the end of the program (by setting LR indicator ON). A simple RPGLE program looks something like this on a high level with out the use of a USROPN.  1 2 3 4 5 6 7 8 9 10 11 **Free                                  Dcl-F TestFile;                            ...
Read more

What is Deep Learning? Beyond the Basics of AI

What is Deep Learning? Beyond the Basics of AI AI’s everywhere—unlocking your phone, suggesting playlists, even driving cars. But how does it get *so* smart? Enter deep learning—a game-changer in artificial intelligence. Welcome to Decoding Complexities , where we unravel tech’s toughest puzzles. If you read “What Are Neural Networks?” you’ve brushed against this. Now, we’re going deeper. In this post, we’ll decode what deep learning is, how it powers AI’s wildest feats, and why it’s more than just buzz. From self-driving Teslas to ChatGPT, it’s the engine behind the magic. Let’s break it down—ready? Deep Learning: The Basics Deep learning (DL) is a subset of machine learning—itself a chunk of AI. Remember neural networks from my last post? DL cranks them up—think neural networks on steroids. It’s all about *deep* neural networks—piles of layers that dig into data to find patterns no human could spot. Here’s the gist: More Layers: Regula...
Read more

What is Artificial Intelligence?

Artificial Intelligence Artificial Intelligence (In short, AI) is a highly sought-after skill in the Tech Industry today. In this post, let's try to understand " What is Artificial Intelligence? ". Before we dive in, let's first understand "What is Intelligence?" As humans, we think and act. This involves understanding our environment, predicting outcomes, and behaving accordingly. Similarly, AI focuses on building machines that can understand, predict, and act/respond effectively and safely. AI isn't exclusive to any specific industry. Its applications spread across different industries, including playing chess, proving mathematical theorems, driving cars, writing poetry, composing music, generating videos, diagnosing diseases, and much more. The field is continually evolving. Initially, AI was often defined in relation to matching ' Human performance '. However, AI has surpassed human capabilities in several areas and ...
Read more