Evaluating label verification options

The label verification options control the processing and storage of labels and the action it takes if it encounters a label mismatch.

You should evaluate the default values for the options to determine whether you need to change them.

This section contains the following topics:

Related topic

Using-the-Integrity-Controller

Checking labels online

You can control whether Database Integrity is invoked to check labels when the database is accessed from the online IMS or CICS environment. The default value is to check labels online. For protection of data integrity, use the default value.

Warning

In the IMS online environment, Database Integrity is invoked to verify labels only at database OPEN time. If you change control blocks with the MODIFY command and the database has not been closed, take special care to verify that the new ACBLIB is correct. You can use Database Integrity to check the contents of the new ACBLIB against the labels, as described in Checking-labels-against-control-blocks-in-batch.

Checking labels in batch

You can control whether Database Integrity is invoked to check labels when the database is accessed from a program or utility running in batch. The default value is to check labels in batch. For protection of data integrity, use the default value.

Checking labels for user load programs

You can control whether Database Integrity is invoked to check labels when the database is accessed by a user load program. The default value is to check labels. For protection of data integrity, use the default value.

Checking labels for image copies

You can control whether Database Integrity is invoked to check labels when the database is accessed by a batch image copy utility. The default value is to check labels. For protection of data integrity, use the default value.

Specifying the label mismatch action

If Database Integrity is invoked to check labels, it can detect that the control block being used to access a database is different from the DBD that was used to load the database.

When it encounters such a label mismatch, the action it takes depends on the option you choose on the Change/Review Global Label or Label Change/Review panel:

D

Reset the DBRC return code to deny DBRC authorization and issue a warning message.

W

Issue a warning message and replace the label if label verification fails. Do not reset the DBRC return code.

You can choose a different action for online and batch environments. The default and recommended value in both environments is to deny DBRC authorization.

Warning

Setting the label mismatch action to W can cause an integrity problem. If a mismatch occurs for a job that is using the wrong control blocks, the bad control blocks are stored in the label; this causes other jobs, which may use the correct control blocks, to fail.

Setting message routing and descriptor codes

The message routing codes and message descriptor codes you can specify are described in the section on the WTO macro in the IBM MVS/ESA Routing and Descriptor Codes documentation. The default message routing code is 2,7,11 (route the messages to the Master Console, Unit Record Pool, and Programmer Information), and the default message descriptor code is 7.

Managing previous versions of labels

For historical or recovery purposes, you can choose to leave previous versions of the label in the label data set. You can specify either the maximum number of label generations to keep or the number of days that previous versions of labels will be kept in the labels data set. The default value is zero (retain no previous versions of the label).

Choosing the label data set

Database Integrity stores the labels in a user-supplied KSDS.

You must create at least one global option module. Database Integrity accesses the global option module during label verification to retrieve the name of the label KSDS. Define the label KSDS according to the following parameters:

KSDS label data set definition

DEFINE  CLUSTER(NAME(imsx.dbilabel) -
  INDEXED                -
  KEYS(24 0 )            -
  SHAREOPTIONS (3,3)     -
  VOLUMES(sysda)         -
  CYL(2 1)               -
  RECORDSIZE(128 4089)   -
  NONSPANNED             -
  NOREUSE                -
  FREESPACE(70 20)       -
  UNORDERED )            -
  DATA(NAME(imsx.dbilabel.DATA)) -
  INDEX(NAME(imsx.dbilabel.INDEX))
Warning

The label data set is integral to the design of the Integrity Controller. If it is lost, Database Integrity cannot continue to prevent control block mismatch errors. When you use a KSDS for the label data set, be sure to include procedures to back up, recover, and maintain this data set as part of a permanent implementation of Database Integrity.



 

Tip: For faster searching, add an asterisk to the end of your partial query. Example: cert*