Creating generation data groups

To create a generation data group (GDG), first create its catalog by using the gdgmgr command with the -c flag. (A GDG catalog is a binary file in the Linux® native file system; a GDG catalog name is of the form gdgBaseName.catalogue.)

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You then populate the GDG with generation files typically by running COBOL programs that create the files.

In the Linux LSQ file system:

To create a GDG catalog in the LSQ, RSD, SdU, or STL file system, use the gdgmgr command with the -c flag. For example, to create catalog ./myGroups/transactionGroup.catalogue, you can issue this command:


gdgmgr -c ./myGroups/transactionGroup

The catalog is created by default in the current working directory (./). You can optionally precede the catalog name in the gdgmgr command with a path name, as shown above. The catalog and the generation files must be created in the same directory.

In the SFS file system:

To create a GDG catalog in the SFS file system, use the gdgmgr command with the -c flag. You can specify the SFS file name in either a fully qualified form or an abbreviated form. For example, the following command creates a GDG catalog using a fully qualified SFS name:


gdgmgr -c /.:/cics/sfs/sfsServer/baseName

You can instead specify an abbreviated form of the SFS file name by first setting environment variable CICS_TK_SFS_SERVER, and then issuing the gdgmgr command using also the -F flag to specify the SFS file system. For example:


export CICS_TK_SFS_SERVER=/.:/cics/sfs/sfsServer
gdgmgr -F SFS -c baseName

To override the default GDG home directory (~/gdg) for SFS groups, set environment variable gdg_home. For example, the following commands create a GDG catalog ~/groups/forSFS/sfs/sfsServer/myGroup.catalogue:


export gdg_home=~/groups/forSFS
gdgmgr -c /.:/cics/sfs/sfsServer/myGroup

All SFS generation files in a given group must be on the same SFS server.

In the Db2® file system:

To create a GDG catalog in the Db2 file system, do the following steps:
  1. Initialize the Db2 environment by running the profile for the Db2 instance that you want to use.
  2. Set environment variable DB2DBDFT to the database for the group.
  3. Use the gdgmgr command with the -F flag to specify the Db2 file system, and with the -c flag. Specify the schema directly in the required catalog name.

For example, the following commands create catalog ~/gdg/db2/db2inst1/database/cics.dbGroup.catalogue:


. /home/db2inst1/sqllib/db2profile
export DB2DBDFT=database
gdgmgr -F DB2 -c cics.dbGroup

The home directory for a GDG catalog for Db2 files is taken from environment variable $gdg_home or else defaults to ~/gdg.

All generation files in a generation data group must be in one database under one schema.

Related concepts  
File systems
Generation data groups

Related references  
Limit processing of generation data groups