Identify datasets opened by a Datacom MUF in z/OS

Products

• Datacom/AD
• Datacom/DB
• Datacom

Issue/Introduction

Is there any Datacom command that lists the datasets currently allocated by a MUF region?

Environment

• Datacom/AD or Datacom/DB Multi-User Facility

Cause

The Datacom MUF manages many database and system datasets (CXX, LXX, FXX, etc.) simultaneously, but its internal interrogation commands (like STATUS) do not provide an OS-level allocation summary.

Resolution

Because there is no internal Datacom command for this, you must use an MVS monitoring tool (like Broadcom SYSVIEW) to view the allocations for the MUF address space.

Using Broadcom SYSVIEW

1. Enter the ASID jobname command where jobname is the MUF jobname
2. Enter the DSALLOC command. This will display a complete list of all datasets currently allocated and opened by the running MUF.

Additional Information

You can estimate the number of open datasets even without using a monitor:

• A MUF region definitely opens libraries in STEPLIB and systems datasets (CXX, LXX, FXX, PXX).
• Then the number of the datasets related to index and data areas currently open can be found running this SQL query:
  SELECT DATASET_NAME FROM SYSADM.DIR_DATASET WHERE DBID IN (SELECT DISTINCT DBID FROM SYSADM.MUF_OPEN_BASES);
  
  Note: This SQL query may not report system databases even if they are open (see Datacom System databases are open but are not in MUF_OPEN_BASES DST article).