Databases Reference
In-Depth Information
Restart Paragraph
1. The IMS Restart call returns the Checkpoint Id value used to restart,
for example: PCIP0007. Before the program takes the next check-
point, it updates the counter field by one. During each Checkpoint
call, IMS automatically displays the Checkpoint ID as well as the sys-
tem date and time. This is a simple way to confirm that restart logic
is processing as expected.
2. Do not initialize any Save-Area fields. The restart call automatically
retrieves the data from the log and updates these fields. You may
need to make sure that the program properly sets up any SQL Fetch
criteria used to guarantee repositioning during a restart from data
previously stored in saved fields.
3. The system automatically opens and repositions both input and out-
put sequential files (GSAMs only) to the correct relative byte ad-
dress as of the checkpoint.
4. Your program is responsible for reopening DB2 cursors and reposi-
tioning any IMS databases. Once again, since the processing path of
secondary database calls should be dictated by data in the transac-
tion record, no special coding considerations should be required.
Sample Program Flow
See Exhibit 20.1 for a sample program flow.
Exhibit 48-1. Sample program flow.
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