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How to analyze and maintain DBD/PSB instances in IMS catalog by using IMS Administration Tool

How To


Summary

IBM IMS Administration Tool for z/OS (IMS Administration Tool) is an IMS Tools product that provides a comprehensive set of functions and features to assist IMS database administrators with managing IMS environments.

The DBD detail report and the PSB detail report, which are generated by the IMS catalog and ACB library management function of IMS Administration Tool, have been enhanced with APAR PH47747. You can use these reports to analyze and maintain database (DBD) instances and program (PSB) instances that are stored in the IMS catalog database. With the enhancements made by APAR PH47747, you can also analyze members that are stored in the ACB library. These reports:
- Lists all instances, including old instances: You can generate DBD and PSB statements by selecting an instance to examine the content of the DBD or PSB.
- Displays the timestamp and the status (active, pending) of each instance: You can check whether the timestamp of the instance is identical to the timestamp of the corresponding member in the IMS directory or ACB library.
- Indicates which instance is not used: You can identify the instances that are not used by IMS and delete obsolete instances to increase free space.

Objective

This information is designed to provide steps on how to analyze and maintain DBD and PSB instances in the IMS catalog database by using the DBD/PSB detail report with the IMS Administration Tool ISPF interface. Specifically, it provides information about the following tasks:
  • Identifying active and staging instances in the IMS catalog database, and checking the consistency of instances with members in the IMS directory (when the IMS management of ACBs is enabled) or ACB library (when the IMS management of ACBs is not enabled).
  • Identifying instances that can be deleted and deleting them.
  • Resolving an instance-member inconsistency.
Notes:
  • Information in the DBD and PSB detail reports is based on the instances found in the IMS catalog database. If, for example, you generate a new DBD member in the IMS directory or ACB library but did not populate the IMS catalog database, the instance of that member does not exist in the IMS catalog database. Therefore, that instance will not appear in the DBD detail report.
  • If you want to check the overall consistency of the IMS catalog database with the IMS directory or the IMS catalog database with the ACB library, use the Compare function of IMS Administration Tool instead of the DBD/PSB detail report.

Steps

Displaying the DBD/PSB detail report

From the IMS Administration Tool ISPF main menu, navigate as follows to display the DBD/PSB detail report:
IMS Catalog and ACBLIB Management > IMS Catalog Space and DBD/PSB Analysis >  View DBD Detail Report or View PSB Detail Report

Scenarios

The following scenarios illustrate how you can use DBD/PSB details reports to analyze and maintain instances in an IMS catalog database.

Scenario 1: Analyzing instances when the IMS management of ACBs is enabled (IMS catalog database and IMS directory)

The following figure shows an example of the DBD detail report when the IMS management of ACBs is enabled.
When the IMS management of ACBs is enabled, the report shows each instance found in the IMS catalog database and their corresponding DBD members found in the IMS directory.
In the report, you can identify DBD members by looking at the Status column. The Status column contains xxx-DIR for members that are found in the IMS directory.
DBD detail report
 
The IMS catalog database stores one or more instances for each DBD. Refer to the timestamp to distinguish among them. You can use line command V to view the DBD statement source.
The Status column shows how the instance or the member is being used by IMS:
ACTIVE, PENDING, ACT-DIR, PEND-DIR
If the timestamp of the instance matches the timestamp of the header segment in the IMS catalog database, the instance is indicated as ACTIVE or PENDING. For corresponding members in the IMS directory, this column is ACT-DIR or PEND-DIR.
In the example report, the timestamps of the AUTODB - PENDING instance and the AUTODB - PEND-DIR member are the same, and the timestamps of the AUTODB - ACTIVE instance and the AUTODB - ACT-DIR member are the same. These indicate that DBD AUTODB is maintained consistently between the IMS catalog database and the IMS directory. If the timestamps do not match, an asterisk (*) is displayed in column C (Condition column).
USABLE
When DB Versioning is enabled, multiple DBD instances with the same DB Version can exist in the IMS catalog database. In this case, IMS application programs refer to the most recent instance. The most recent instance that is referred to by IMS application programs is indicated as USABLE.
OBSOLETE
OBSOLETE indicator is for old instances that are not referenced by IMS.
(LOGICAL)
This is a logical DBD and the latest timestamp instance.
IMS does not store logical DBD blocks in IMS directory active or staging data sets. Also, there are no active or pending timestamps in the header segment of the IMS catalog database. For this reason, (LOGICAL) is set instead of ACTIVE or PENDING.

Notes: In this report, some fields are blank.
  • Pointed by PSB(#) column is blank for instances and members that are not applicable.
  • Size in IMS Catalog (B) column is blank for members found in the IMS directory.
  • DB Version column is blank for members found in the IMS directory. To check the DB version of the member, use line command V and locate the DB version in the DBD statement source.

Scenario 2: Analyzing instances when the IMS management of ACBs is disabled (IMS catalog database and ACB library)


The following figure shows an example of the DBD detail report when the IMS management of ACBs is not enabled.
When the IMS management of ACBs is not enabled, the report shows each instance found in the IMS catalog database and their corresponding DBD members found in the ACB library.
In the report, you can identify DBD members by looking at the Status column. The Status column contains xxx-ACBL for members that are found in the ACB library.
DBD detail report when the IMS management of ACBs is disabled
 
The IMS catalog database stores one or more instances for each DBD. Refer to the timestamp to distinguish among them. You can use line command V to view the DBD statement source.
The Status column shows how the instance or the member is being used by IMS:
ACTIVE, PENDING, (ACTIVE), (PENDING), ACT-ACBL, PEND-ACBL
The status indicators for instances are different depending on whether the header segment of the IMS catalog database contains active/pending timestamps:
  • Case 1: If the header segment contains an active or pending timestamp, the instance whose timestamp matches that timestamp is indicated as ACTIVE or PENDING.
  • Case 2: If the header segment contains no active or pending timestamp, the instance whose timestamp matches the timestamp of its corresponding member in the ACB library is indicated as (ACTIVE) or (PENDING).
Whether the header segment contains a timestamp or not depends on if MANAGEDACBS=SETUP was specified when the IMS catalog was created with the IMS Catalog Populate (DFS3PU00) utility. For example, if the IMS catalog database is shared by an IMS system that has the IMS management of ACBs enabled and another IMS system that has the IMS management of ACBs disabled, the header segment contains a timestamp.
For corresponding members in the ACB library, this column is ACT-ACBL for members found in the active ACB library, and PEND-ACBL for members found in the staging ACB library.
In the example report, the timestamps of the ACTIVE instance and the ACT-ACBL member are the same, and the timestamps of the PENDING instance and the PEND-ACBL member are the same. These indicates that DBDs are maintained consistently between the IMS catalog database and the ACB library. If the timestamps do not match, an asterisk (*) is displayed in column C (Condition column).
(INACT), INACT-ACBL
If the timestamp of an instance matches the timestamp of a member that is in an inactive ACB library, that instance is indicated as (INACT). The corresponding member is indicated as INACT-ACBL.
USABLE
When DB Versioning is enabled, multiple DBD instances with the same DB Version can exist in the IMS catalog database. In this case, IMS application programs refer to the most recent instance. The most recent instance that is referred to by IMS application programs is indicated as USABLE.
OBSOLETE
OBSOLETE indicator is for old instances that are not referenced by IMS.
(LOGICAL)
This is a logical DBD and the latest timestamp instance.
IMS does not store logical DBD blocks in the ACB library. Also, there are no active or pending timestamps in the header segment of the IMS catalog database. For this reason, (LOGICAL) is set instead of ACTIVE or PENDING.
Notes: In this report, some fields are blank.
  • Pointed by PSB(#) column is blank for instances and members that are not applicable.
  • Size in IMS Catalog (B) column is blank for members found in the ACB library.
  • DB Version column is blank for members found in the ACB library. To check the DB version of the member, use line command V and locate the DB version in the DBD statement source.

Scenario 3: Identifying instances that can be deleted and deleting them

If the data sets of the IMS catalog database are becoming full and you want to increase free space, consider deleting unused (obsolete) instances. DBD/PSB detail report helps you easily identify and delete unused instances.
  • Use line command V to examine the content (DBD/PSB statement source) of the DBD/PSB instance before deleting it.
  • Use line command D to delete an obsolete instance.
  • Use primary command D to delete all obsolete instances at once.
If you delete instances multiple times, free space in the IMS catalog database data sets might become fragmented. You can use IMS High Performance Pointer Checker or IMS full-function Database Sensor to identify space fragmentation. If you identify fragmentation, consider reorganizing the data sets.

Scenario 4: Resolving an instance-member inconsistency


If an instance-member inconsistency is found, you must resolve the inconsistency.
The following figure is an example of the DBD detail report when inconsistencies are found. Some asterisks (*) are displayed in column C (condition column).
Note: This example is when the IMS management of ACBs is enabled, but the steps to resolve inconsistencies when the IMS management of ACBs is disabled are the same. 
DBD detail report - inconsistency detected
 
Look at AUTODB - PENDING and AUTODB - PEND-DIR. Line AUTODB - PENDING is the instance that has the same timestamp as the pending timestamp in the header segment of the IMS catalog database, and line AUTODB - PEND-DIR is the corresponding member found in the IMS directory staging data set. They both have an asterisk in column C, indicating that the timestamps of these two resources do not match.
To resolve the inconsistency, you can do as follows:
  1. Use line command V to examine the content (DBD statement source) of the instance and the member, and identify which of them has the correct DBD statements.
    If you want to view all differences between the instance and the member, use the Compare function of IMS Administration Tool.
  2. By using the correct instance or member, run the Resource Change function of IMS Administration Tool to generate DBD statements for DBD AUTODB.
  3. Run DBDGEN, ACBGEN, and then populate the IMS catalog database.

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Document Information

Modified date:
22 September 2022

UID

ibm16620637