Index requirement for DBUTLTY SEQ=NATIVE backup in Datacom

Products

• Datacom

Issue/Introduction

When performing a database move or maintenance using Datacom DBUTLTY, you may encounter failures during the backup step if using Native sequence. This article explains the architectural requirement for an index when using SEQ=NATIVE versus SEQ=PHYSICAL and how to resolvebackup failures during database migrations.

Environment

Z/OS

Datacom ( Datacom/DB and Datacom/AD) 

Cause

For a DBUTLTY SEQ=NATIVE backup to run successfully, the index (IXX) must exist and be valid. The Native sequence backup utilizes the index to process records in their logical order. If the index does not exist for the tables in the database (e.g., following an INIT of the area without a subsequent LOAD or RETIX), the Native backup fails. .

Conversely, BACKUP SEQ=PHYSICAL (or SEQ=PHY) processes the data area sequentially by physical blocks and does not require the index to be present or valid.

Resolution

If you are moving a database (e.g., moving to new 3390 volumes) and need to rebuild the index during the process, use the following sequence (after closing the DBID ) :

1. Perform a Physical backup of the source database:

   BACKUP DBID=####,SEQ=PHYSICAL,DDNAME=

2. Initialize the Index Area (IXX) and Data Areas on the new volume:

   INIT AREA=IXX,DBID=####INIT AREA=###,DBID=#####

3. Run the LOAD step using the physical backup created in step 1. The index is automatically recreated during the LOAD process:

   LOAD DBID=####,FORMAT=BACKUP,SORT=1,SORTDFLT=YES,OPTIMIZE=YES,DDNAME=

Additional Information

For a 24x7 move , see Move Index and Data Areas While Databases are Online.