Dynamic file allocation in DMCL

Products

• IDMS

Issue/Introduction

Is dynamic allocation commonly used in production environments? 

If adding new files, would there be any problems adding the new files with dynamic allocation so as to minimize impact to batch JCL? The current files would be JCL defined.

Environment

Release: All supported releases.

Resolution

Yes, it is commonly used. Be careful when using both JCL and DSNames defined in DMCL FILE definitions.

For example: 
If dataset names defined in the DMCL are changed, but somebody has a local batch JCL with DD overrides pointing to obsolete files, that would be a big problem. 

The specific scenario being identified here is this: 

AREA-1 consists of two files and the DD/DSNs are coded in a lot of JCL, CV and Batch. 

Now AREA-1 is expanded to consist of four files. The first two will be the exact same DSNames and the new ones would be added with their DSNames in the DMCL. This way the new files would not need to be added to all of the JCL that accesses the area in question as long as those jobs are using the updated DMCL. 

That will work well.

Additional Information

Database Administration