Product considerations

APF-authorized environment

The utility must be able to execute briefly as an authorized program at various times during processing.

Therefore, the utility attempts to establish an APF-authorized environment as follows:

1. The utility determines whether the product modules are being loaded from an APF-authorized STEPLIB, JOBLIB, or LNKLST concatenation of libraries:
   • If the libraries are APF authorized, the utility obtains authorization through conventional methods.
   • If the libraries are not APF authorized, the utility proceeds to step 2.

2. The utility determines whether the DBUSSID keyword is specified on the GLBL control statement or in the global options module:

   • If the keyword specifies the subsystem ID of a Database Utilities Subsystem (DBUSS) that is active in the environment, the utility obtains authorization through that DBUSS.
   • If the keyword is not specified on the GLBL control statement or in the global options module, the utility proceeds to Step 3.
   • If the keyword specifies an inactive DBUSS, the utility proceeds to step 4.

   For more information about the DBUSS, see DBUSSID-keyword.

3. The utility determines whether the default DBUSS (subsystem ID DBUZ) is active:
   • If DBUZ is active, the utility obtains authorization through DBUZ.
   • If DBUZ is not active, the utility proceeds to step 4.
4. The utility searches for an active Cross-Product Connectivity (CPC) subsystem:
   • If a CPC subsystem is active in the environment, the utility obtains authorization through that subsystem and reports the subsystem ID in an informational message.
   • If no CPC subsystem is active, the utility issues an error message and terminates abnormally.

The CPC subsystem is found automatically, you do not need to provide the subsystem ID.

HALDB Considerations

The Change Accumulation utility provides complete support for High Availability Large Databases (HALDBs).

The default value for the HALDB keyword is Y. You must not specify the HALDB(N) keyword on the GLBL statement in the ICPSYSIN data set of the utility job step. Additional considerations and instructions apply to use of the IIC function with HALDBs. For more information, seeIMAGE COPY PLUS documentation.

Point-in-time change accumulation considerations

Several considerations apply to the production of a point in time (PIT) change accumulation (CA). For details, see PIT-change-accumulation.

IMS HALDB Online Reorganization

The Change Accumulation utility provides toleration support for IMS HALDB Online Reorganization (OLR) as follows (if you have IMS 8.1 or earlier, OLR support is disabled):

• A point-in-time (PIT) change accumulation cannot be performed to a time when OLR is actively performing a reorganization. No additional considerations apply to standard change accumulation processing.
• The image copy process can be performed only when OLR is not actively performing a reorganization. The utility ignores any commands to create image copies if an online reorganization is in progress. Dynamic allocation for HALDBs is recommended so that the utility automatically can select the active data set group for processing. No control statement changes are necessary.
• Incremental image copy processing is not allowed unless an input image copy is present.

DFSUCUM0 functions

The following control statement functions provided by DFSUCUM0 are not supported:

• DB1 *ALL
• DB1dbdname
• SO

Recovery Manager (RMGR)

If you want to use the Recovery Extensions feature to access RMGR groups or to manage additional recovery assets, the Recovery Manager functions and utilities of the BMC AMI Backup and Recovery for IMS product or the RECOVERY MANAGER for IMS product must be active.

For more information about RMGR and the Recovery Extensions feature, seeRECOVERY MANAGER for IMS documentation.

Recovery Advisor exceptions in the console

The Image Copy utility, the Change Accumulation utility, and the Recovery utility interact with Recovery Advisor in the console.

One important interaction is the automatic clearing of certain Recovery Advisor exceptions at successful creation of an image copy or change accumulation data set and at successful recovery of a database.

Supporting IMS-managed ACB

BRI utilities support the use of IMS-managed ACB. This functionality can be activated by:

• Setting the BMC global option keyword IMSMACB to YES in the DLIGSET0, or by providing a BMCSETUP DD statement in the JCL containing IMSMACB(Y) keyword as follows:
         //BMCSETUP DD *
         IMSMACB(Y) 
  The default value for the IMSMACB keyword in DLIGSET0 is changing to Yes. This makes the job step eligible for the IMS-managed ACB processing by the BRI utilities.

  Warning

  Important

   The default value has been "N" up through RSL2307.

• Providing one of the following for the BRI utilities to verify that an IMS-Managed ACB environment exists:
  • IMS Catalog user exit (DFS3CDX0) in the STEPLIB, JOBLIB or linklist library.
  • DFSDFxxx Procedure library member. The required member suffix for the PROCLIB can be specified using the keyword PARM=’DFSDF=xxx’ on the job step’s EXEC statement and by including a //PROCLIB DD containing the matching parameter member. 
• Providing information for the utilities to find the IMS catalog data set high level qualifier by one of the following methods:
  • An MDA member mapping the Catalog bootstrap data set.
  • From the Catalog database definitions in the RECON datasets.

The utilities allow the IMS catalog ALIAS names defined using the catalog exit (DFS3CDX0) or the DFSDFxxx PROCLIB member to support the IMS environment with multiple catalogs.  

The following table describes how the staging or active directory is accessed in the CHANGE ACCUMULATION PLUS component.

Utility	ACBLIB environment	Directory to read the database		Alternate via keyword(NEWDBD- Value S)
		Default Directory	Alternate via keyword(NEWDBD- Value A)
ICPUMAIN	IMSACB	ACTIVE	ACTIVE only	Search the STAGING library first, if not found then search in the ACTIVE directory.
RVPUMAIN	IMSACB	ACTIVE	ACTIVE only	Search the STAGING library first, if not found then search in the ACTIVE directory.
CAPUMAIN	IMSACB	ACTIVE	ACTIVE only	Search the STAGING library first, if not found then search in the ACTIVE directory.

Unsupported versions of IMS

If you are using a version of IMS that is no longer supported by IBM, new and recent enhancements to the Change Accumulation utility might be unavailable.

For example, dynamic allocation models are not available for IMS Version 6.1 or earlier.

General considerations

The following general considerations apply to the use of the Change Accumulation utility:

• Change accumulation of a shared secondary index data set is supported if you specify the first shared secondary index in the change accumulation group.
• You must use Change Accumulation utility format control statements (in the CAPSYSIN data set) if you process multiple change accumulation groups in a single job step.
• The Change Accumulation utility does not support dynamic allocation of predefined image copy data sets for databases that are defined with the REUSE option in the DBRC RECON data set. If you use the REUSE option, you must allocate the correct image copy data sets in the JCL.
• The Change Accumulation utility supports the IBM IMS Partition Support Product (Partition DB). However, the partitioned indexes that are available with the Partition DB version 2 are not supported.