DBRC considerations for HALDB Online Reorganization
The following topics describe the DBRC considerations with respect to HALDB online reorganization.
The following DBRC commands support HALDB online reorganization:
- CHANGE.DB
- GENJCL.IC and GENJCL.OIC
You can generate the JCL for the GENJCL.IC and GENJCL.OIC commands in advance and not execute the JCL immediately. Therefore, the active set of DBDSs might change in the interim time period.
GENJCL no longer generates DD statements for the HALDB DBDS that is being copied because dynamic allocation is recommended for the Database Image Copy utility and the Database Image Copy 2 utility. The SYSIN control statement identifies which DBDS to copy: either the A-through-J or the M-through-V set of data sets. The image copy utility then copies the corresponding active set of data sets: A-through-J or M-through-V.
- INIT.DB
- NOTIFY.IC, NOTIFY.REORG,
and NOTIFY.UIC
You cannot take an image copy if a HALDB online reorganization cursor is active (OLREORG CURSOR ACTIVE =YES) or has been terminated. The NOTIFY.IC and NOTIFY.UIC commands fail if they attempt to record an image copy while the HALDB online reorganization cursor is active.
HALDB online reorganization relies on a number of records to track information and activities related to online reorganization. This section includes descriptions of some of the records impacted by HALDB online reorganization:
- HALDB master record
- Partition DB record The DB record for a HALDB partition contains information for HALDB online reorganization. For a complete description of the fields in the DB record for a HALDB partition, see
Fields present in a listing of a RECON by record type
in IMS Version 15.4 Commands, Volume 3: IMS Component and z/OS® Commands. The DB record includes:- A field that indicates whether the database can be reorganized
online (ONLINE REORG CAPABLE=). This field is also in the HALDB master
DB record. This field cannot be reset if:
- Online reorganization is active
- Any of the M-through-V and Y data sets are active
- Any partition for the HALDB is authorized
If these conditions do not exist and the field can be reset, all of the M-through-V and Y data set information in the RECON data set is deleted.
- A field that indicates whether the HALDB online reorganization cursor is active (OLREORG CURSOR ACTIVE=).
- The SSID of the IMS that is currently performing a HALDB online reorganization (OLRIMSID=).
- A field that indicates which set or sets of DBDSs is or are active for the partition (ACTIVE DBDS=).
- A field that indicates whether the database can be reorganized
online (ONLINE REORG CAPABLE=). This field is also in the HALDB master
DB record. This field cannot be reset if:
- DBDS record
The M-through-V and Y DBDS records are defined in the RECON data set with the same attributes as the corresponding A-through-J, L, and X DBDS records. The M-through-V and Y DBDS records are added to the same CAGROUP as the A-through-J and X DBDS. Similarly, the M-through-V and Y DBDS records are added to each DBDS group where the A-through-J DBDS records are found.
The exceptions to the similarities in attributes include DD names, data set names, and the DSID. The DSID of the M-through-V and Y data set is the same as the corresponding A-through-J, L, and X data set, except that its X'80' bit is set on. For the RECON data set list purposes, the X'80' bit is ignored.
The following table shows the data set ID (DSID) DCB number associated with the A-through-J, L, and X data sets and the M-through-V and Y data sets.
Table 1. DSID DCB numbers for the A-J, L, and X and the M-V and Y data sets DSID DCB Number A-J, L, and X Data Sets M-V and Y Data Sets PHIDAM PHDAM PHIDAM PHDAM 1 A A M M 2 3 L L 4 B N 5 X C Y O 6 B D N P 7 C E O Q 8 D F P R 9 E G Q S 10 F H R T 11 G I S U 12 H J T V 13 I U 14 J V - REORG record
The REORG record for a HALDB partition DBDS contains a stop time for HALDB online reorganization. To run an offline reorganization of a database, you must take it offline by issuing a /DBR command. Therefore, only the start time of the online reorganization is significant. With HALDB online reorganization, the database is online, so the duration of the process is significant. The stop time of the online reorganization is recorded in the REORG record (STOP=timestamp), with information that indicates that it is an online reorganization and indicates whether the online reorganization can be used as input to recovery.
Related reading: For more in formation on Fields present in a REORG record, see IMS Version 15.4 Commands, Volume 3: IMS Component and z/OS Commands.
A REORG record is recorded under both the A-through-J, L, and X DBDS and the M-through-V and Y DBDS. The REORG record for the DBDS that was the output data set indicates that it can be used as input for recovery. The REORG record for the DBDS that was the input data set indicates that it cannot be used for recovery after online reorganization completes.