DBUTLTY OLREORG with REFGROUP=0 for Disk Backup and Restore tables

Products

• Datacom
• Datacom/DB
• Datacom/AD
• DISK BACKUP AND RESTORE
• Disk Backup and Restore - MVS

Issue/Introduction

What are the required steps to set up Datacom OLREORG (Online Reorg) with REFGROUP=0 in order to perform a reorganization of the Disk Backup and Restore tables?

Resolution

OLREORG with REFGROUP=0 requires the Data Space Option (DSOP) attribute set to 4 or 5. This requires PTF RO90201 (Disk Backup and Restore V12.5, titled "ARCHIVE U0100 ABEND DUE TO INCORRECT RCF KEYS" to change the DSOP value from 1 to 4 (RANDOM FOR OLREORG).

Because this utility makes use of empty blocks, it is necessary that there is at least 30% free space in the area being reorganized.

Here are the steps to follow to prepare the Disk DMS Area to use OLREORG with REFGROUP=0:

1. Apply all Datacom PTFs related to OLREORG.
2. Check if there is enough free space on the DMS area and on the volumes where it's allocated; if not, extend the area (see article "How to extend a Datacom area while the database is open")
3. Check if the DSOP value is already set to 4 (RANDOM FOR OLREORG): run a DBUTLTY CXX report for the Disk database and search for the "DSOP MODE" string for the DMS area. If the value is not "RANDOM FOR OLREORG", then you can dynamically change it running these additional steps:
   1. Run PGM=DBUTLTY with the following cards:
      

      //SYSIN    DD *
       CXXMAINT  DBID=nnn,AREA=DMS,OPTION=ALTER,DSOP=4
      /*

   2. Run DBUTLTY to rebuild the space index:
      

      //SYSIN    DD *
       DATASCAN  DBID=nnn,AREA=DMS,OPTION=REBUILD_SPACE_INDEX
      /*

   3. Run DBUTLTY to close and immediately reopen the Disk database to commit the changes:
      

      //SYSIN    DD *
       ACCESS    DBID=nnn,STATUS=OFF,USERS=WAIT  
       COMM      DBID=nnn,OPTION=CLOSE
       ACCESS    DBID=nnn,STATUS=WRITE
       COMM      OPTION=CONSOLE,OPTION2='OPEN_BASE nnn'
      /*        

4. At this point, the Disk area is ready for the OLREORG with REFGROUP=0 process; run DBUTLTY on each table:

   //SYSIN    DD *
    OLREORG   DBID=nnn,TABLE=ttt,REFGROUP=0
   /*

Additional Information

Important notes:

• The very first OLREORG on a table could take several hours to complete (it could run longer than 24 hours, depending on the number of rows on the table and how badly the data are currently organized); you can cancel the OLREORG job (or REQABORT the related Datacom request) and then resubmit the job later.
• The process will cause a number of SPILL requests during the execution, and they must be run immediately to avoid MUF to stop performing the updates. This is because LXX has to record each and every row that is moved by OLREORG.

For more information about the OLREORG process, please review the documentation topic OLREORG (Reorganize a Database Online).

As always, please contact Broadcom support for Datacom if you have further questions.