This document provides information and recommendations for using the IMS Catalog. Key points include: - The Catalog acts as a metadata repository but is not a full data dictionary. It lacks definitions for business elements. - Catalog structures are based on time stamps rather than relationships between changes. - Multiple datasets may be needed to partition the Catalog data by DBD and PSB. - Operational procedures include the DFSU3ACB utility and CATPOP job to update the Catalog. Image copies are recommended.

1. Course materials may not be reproduced in whole or in part without the prior written permission of IBM. 5.1
IBM Software Group
®
8GB OSAM for HALDB
IMS Catalog
Rick Long – IMS Advanced Technical
& integration testing Team
ricklong@au1.ibm.com

2. © Copyright IBM Corporation 2015
Software requirements
• All IMS data sharing systems at IMS 13 or 14
– RECON MINVERS(‘14.1’)
• if all systems at V14
– RECON MINVERS (‘13.1’)
• if APAR PI23918 for a V13 systems
• Cross-DBRC Service Level ID (CDSLID) to 2
• First time the cross service level id has been used

3. © Copyright IBM Corporation 2015
Design Assumptions
• OSAM HALDB database that is 8 GB capable cannot
run the HALDB online reorganization process, including
HALDB ALTER
• HALDB online reorganization support for an OSAM
HALDB database would still be limited to 4 GB
• The 8 GB HALDB capacity can only apply to HALDBs
that are OSAM
• All partitions become 8GB capable

4. © Copyright IBM Corporation 2015
DBRC Commands
• RECON commands
– CHANGE.RECON MINVERS(‘14.1’)
– CHANGE.RECON MINVERS(‘13.1’)
– CHANGE.RECON CDSLID(0002)
• DB commands
– INIT.DB DBD(masterdbd) TYPHALDB OLRNOCAP
OSAM8G
– CHANGE.DB DBD(masterdbd) OLRNOCAP OSAM8G
• Fallback
– PARTITION INIT NEEDED’ flag is turned on when changing
from OSAM8G to NOOSAM8G
– Unload before resetting back to NOOSAM8G

5. © Copyright IBM Corporation 2015
Operational Considerations
• DBRC commands are used to enable the 8 GB OSAM
HALDB capacity
• INITIATE OLREORG command to an 8 Gigabyte
OSAM HALDB results in a command completion code
of 1EF
• No data set implications other than number of extents
available
• CHANGE.DB can’t be processed while database is
AUTHORIZED

6. © Copyright IBM Corporation 2015
Operational Considerations
• ACTIVE datasets must be A-J
• Image Copies must be taken for PRILOG record
compression (test systems included)
• Add IMS Catalog to a CA Group
• Consider using DB QUIESCE to create recovery points
– UPDATE DB NAME(DFSCD000,DFSCX000)
START(QUIESCE)
– QUIESCE point before allows for recovery if needed
– QUIESCE point after update step would close the ALLOC
and allow for better recovery situation later
• Don’t want to process the logs for the life of the PRILOG

7. © Copyright IBM Corporation 2015
Implementation Considerations
1. DBR masterdbd
2. CHANGE.DB DBD(masterdbd) OLRNOCAP
OSAM8G
3. START DB masterdbd
• Can be done after U0844 abend (DB full condition)
• No implications to data set allocations except the
number of extents allowed for OSAM
– Don’t need to reallocate
– Partitions are independent of each other

8. © Copyright IBM Corporation 2015
LIST.DB
DB
DBD=A1EMPLP DMB#=55 CHANGE#=5
TYPE=HALDB
SHARE LEVEL=3 GSGNAME=**NULL**
DBRCVGRP=**NULL**
PSNAME=**NULL** DBORG=PHIDAM DSORG=OSAM8G CURRENT PARTITION ID=00005
FLAGS: COUNTERS:
RECOVERABLE =YES PARTITIONS =5
ONLINE REORG CAPABLE =NO DATA SET GROUP MEMBERS =1
ALTER COUNT =0
ALTER COMPLETE COUNT =0

9. © Copyright IBM Corporation 2015
New Messages
• DSP1206E Parameter parameter-value IS NOT
ALLOWED DUE TO INVALID MINVERS VALUE
– Explanation The parameter was specified with an invalid
MINVERS level.
– The value of MINVERS level must be 14.1 to use the
OSAM8G or NOOSAM8G keywords.
– System action
• The command is terminated, and subsequent commands are
ignored.
– User Responses
• Use the CHANGE.RECON command to correct the value of the
MINVERS level, and then resubmit the command. For information
about the CHANGE.RECON command, see CHANGE.RECON
command.

10. © Copyright IBM Corporation 2015
Messages
• Changed description (to include
OSAM8G|NOOSAM8G condition)
– DSP0105I parm1 PARAMETER SPECIFIED WITHOUT
CORRESPONDING parm2 PARAMETER
–DSP0195I keyword KEYWORD IS NOT ALLOWED FOR
THIS DL/I PARTITIONED-DB RECORD DBDNAME=db
name
–DSP0222I SPECIFIED PARAMETERS CONFLICT
–DSP0224I SPECIFIED PARAMETERS ARE NOT
ALLOWED

11. Course materials may not be reproduced in whole or in part without the prior written permission of IBM. 5.1
IMS Catalog Recommendations

12. Course materials may not be reproduced in whole or in part without the prior written permission of IBM. 5.1
IMS Catalog is a Catalog not a
Dictionary
© Copyright IBM Corporation 2015

13. © Copyright IBM Corporation 2015
Catalog not Dictionary
• This is a catalog not a dictionary
• Business elements are not defined outside of an
individual structure
– No uniform definition of an elements attributes
– No way to reference where it is used
– No unique name to define an element
• No retrieval of referential information other than PSB –
DBD level
• All structures are time based and not always related to
changes
– PSB get a new timestamp when genned because of DBD
changes 13

14. © Copyright IBM Corporation 2015 14
Metadata principles
• Simply defined, metadata is data about data.
– IMS example: metadata about an IMS database segment might include information
about data types, application-defined fields, user-defined types
• Metadata is not a means to an end
– Users use tools; tools manage and interact with metadata
• Metadata should
– Enhance understanding
– Improve consistency
– Improve impact analysis
– Improve productivity
– Improve governance
• Metadata needs to be linked
– For impact analysis
– For understanding data lineage
• Metadata needs to include physical implementation, logical design intent
and business semantics

15. Course materials may not be reproduced in whole or in part without the prior written permission of IBM. 5.1
Data sets
© Copyright IBM Corporation 2015

16. © Copyright IBM Corporation 2015
Catalog Structure
• Root Key – TYPE – IMSNAME
– DBD dbdname
– PSB psbname
• Level 2 is DBD/PSB Instances – based on
CATVERS/timestamp
– CATVERS is DBVER= for DBD
– CATVERS is 1 for PSB (future use)
– Created by ACBGEN
© Copyright IBM Corporation 2015
HEADER
TYPE/IMSNAME
DBD
CATVERS/TSVERS
PSB
CATVERS/TSVERS

17. © Copyright IBM Corporation 2015
Catalog Datasets
• Plan on more than 1 partition
• Partition by DBD and PSB at least
– DBD
• Number of SEGM and FIELD statements
• Number of different mapping cases
– PSB
• Number of PCBs
• Number of SENSEGs
• PSB partitions might have large Instances of PSB given
the number of PCB
17

18. © Copyright IBM Corporation 2015
Catalog Datasets
• Large Block size – 8K
– ACBGEN can insert a large number of DB records into the
catalog
– 90% of the access with READ
• Default DFSDF member to hold many instances
– RETENTION=(VERSIONS=010)
– Use the UPDATE card when purging instances
– Nothing is purged outside of the purge utility
18

19. Course materials may not be reproduced in whole or in part without the prior written permission of IBM. 5.1
Operational Procedures
&
Utilities
© Copyright IBM Corporation 2015

20. © Copyright IBM Corporation 2015
DFSU3ACB Verses CATPOP
• Only updated by ACBGEN processing (v13)
– V14 allows DDL update access
• ACBGEN + Update step
– Only changed ACBs are passed to the update step
– ACBGEN OK but update step fails
• Can leave “dead” instances in the catalog
• “dead” instances don’t cause a problem other than wasting space
• CATPOP
– All ACBs are inserted
• Same timestamp once are not replace and bypassed
• Report indicates what would have been added
• Both run as BMP
– Don’t need to interrupt active work 20

21. © Copyright IBM Corporation 2015
Multiple ACBLIBs
• Duplicate ACB members with duplicate names are
handled differently
– Single DD
• does not check the ACB time stamps of ACB members with
duplicate names.
• If duplicate member names only first is used regardless of
timestamps
– Multiple DD (IMSACBxx)
• Checks the ACB time stamps of ACB members with duplicate
names
– Same time stamp - only one instance inserted
– Different time stamps – Both instances inserted
21

22. © Copyright IBM Corporation 2015
Operational Considerations
• Perfect choice for a 24X7 database
– Low update volume
– Scheduled updates
– OLR capable
• Image Copies must be taken for PRILOG record
compression (test systems included, online updates)
– Catalog a registered DB in the RECON
– Consider making IC processing part of the ACBGEN change
control process
– IC scheduled after updates

23. © Copyright IBM Corporation 2015
Operational Considerations
• Add IMS Catalog to a CA Group
– You don’t keep logs long enough (test systems)
– Months between updates or IC
• Consider using DB QUIESCE to create recovery points
– UPDATE DB NAME(DFSCD000,DFSCX000)
START(QUIESCE)
– QUIESCE point before allows for recovery if needed
– QUIESCE point after update step would close the ALLOC
and allow for better recovery situation later
– Start concurrent IC in the QUIESCE

24. © Copyright IBM Corporation 2015
Operational Considerations
• Catalog Copy utility can be used to copy ACBs and
catalog instances from one IMS to another

25. © Copyright IBM Corporation 2015
Current Issues
• Catalog Defaults to RD on IMS start-up
– APAR will provide a way to default it to UP
• Purge process a bit awkward
– Suggest retention period in DFSDF member be high
– Use UPDATE control card for purge processing
– Can’t remove failed ACBGEN attempt to drop instances
added without dropping last good one
• Set removal list to include “dead instances” in ANALYSE mode then
edit PURGE file
• Number of locks held during Catalog update step
(APAR open)
– PSBs can contain many PCB and many SENSEG
– PSBs can been re-genned by DBD change
25