Enabling recoup optimized chain chasing

Before you can use recoup optimized chain chasing, you must configure the z/TPFDF index and detail files that you want to use z/TPFDF recoup optimized chain chasing for.

Before you begin

  • Identify the z/TPFDF index file, detail file, and the backward index path from the detail file back to the index file that you want to enable z/TPFDF recoup optimized chain chasing.
  • Ensure that the z/TPF system and the selected z/TPFDF index and detail files meet the requirements to use recoup optimized chain chasing.

About this task

This task enables recoup optimized chain chasing for one index path between the index and detail file and can be repeated for other index paths as needed.

Procedure

  1. For the z/TPFDF index file, if the ID1 parameter is not set to RCPOPTIDX, complete the following steps:
    1. Set the ID1 parameter on the DBDEF macro to RCPOPTIDX.
    2. Assemble and load the program that contains the changed DBDEF macro statement.
    3. Build the DBDEF index table again by entering the ZUDFM DEF command with the INIT parameter specified.
    Note: If z/TPFDF recoup optimized chain chasing was previously enabled on this index file for other index paths, the ID1 parameter is already set to RCPOPTIDX.
  2. For the z/TPFDF detail file, complete the following steps:
    1. For the backward index path that you want to enable z/TPFDF recoup optimized chain chasing for, set IMI bit 4 on the DBDEF macro.
    2. Assemble and load the program that contains the changed DBDEF macro statement.
    3. Build the DBDEF index table again by entering the ZUDFM DEF command with the INIT parameter specified.
    Note: If you are enabling recoup optimized chain chasing for an existing index path, this procedure enables recoup optimized chain chasing only for references that are created by indexing the detail subfile with this path after step 2c. References that are created by indexing the detail subfile with this path before step 2c will not use recoup optimized chain chasing.
  3. To enable optimized chain chasing in recoup, enter the ZRECP PROFILE command with the DFOPTMZ parameter set to ENABLE. This step needs to be done only one time; the setting will be used on all subsequent recoup runs.