Setting your checkpoint frequency

FM/IMS uses three types of checkpoint frequency counters:

Edit Checkpoint Frequency
When AUTOSAVE is on, FM/IMS increments a count by 1 each time you press an action key (for example, Enter, a scroll key such as F8 or F7, and so on) and data changes have been requested. When the counter is equal to the number specified in the Edit Checkpoint Frequency field, FM/IMS commits the data, issues a checkpoint and resets the counter.
Change All Checkpoint Frequency
Because the CHANGE ALL command can affect so many segments in one action, the number of segments that are changed are recorded in a separate counter. When AUTOSAVE is on, FM/IMS increments this count by 1 each time a segment is updated during a CHANGE ALL operation and commits the data, issues a checkpoint and resets the counter when the count is equal to the number specified in the Change All Checkpoint Frequency field. If a checkpoint is issued at any point during a CHANGE ALL operation, a final checkpoint is issued at the end of the operation, so that you cannot roll back to a point midway through the changes.
Batch Checkpoint Frequency
This value is used to determine the frequency of checkpoints when running a File Manager/IMS batch update job. FM/IMS increments a count by 1 each time your batch update job updates, deletes or inserts a segment and issues a checkpoint when the count is equal to the number specified in the Batch Checkpoint Frequency field.

To set your checkpoint frequencies:

  1. From the Primary Option Menu, select option 0 Settings and then option 6 Subsystem. The Subsystem Settings Menu is displayed. On this panel, select either option 4 DLI mode Options if you want to change the DLI mode settings, or option 6 BMP mode Options if you want to change the BMP mode settings and enter in the Subsystem name field, the ID of the subsystem that you want to set your options for. Then press Enter to display either the DLI Mode Options or BMP Mode Options panel.
  2. Enter a value between 1 and 99 in the Checkpoint Frequency: Edit field. In a production environment, it is common to have a checkpoint frequency of 1.

    The value is used in DLI mode. It is also used in BMP mode when your installation allows you to change the autosave settings of the IMS subsystem.

  3. Enter a value between 1 and 9,999 in the Checkpoint Frequency: Change all field.

    The value is used in DLI mode. It is also used in BMP mode when your installation allows you to change the autosave settings of the IMS subsystem.

  4. Enter a value between 1 and 99,999 in the Checkpoint Frequency: Batch field.
  5. Press the Exit function key (F3) to save your changes and return to the Subsystems Settings menu.