Resolving IMS residual recovery entries

You can resolve IMS residual recovery entries (RREs).

About this task

At certain times, IMS builds a list of residual recovery entries (RREs). RREs are units of recovery about which Db2 might be in doubt. RREs occur in the following situations:

If Db2 is not operational, IMS has RREs that cannot be resolved until Db2 is operational. Those are not a problem.
If Db2 is operational and connected to IMS, and if IMS rolled back the work that Db2 has committed, the IMS attachment facility issues message DSNM005I. If the data in the two systems must be consistent, this is a problem situation.
If Db2 is operational and connected to IMS, RREs can still exist, even though no messages have informed you of this problem. The only way to recognize this problem is to issue the IMS /DISPLAY OASN SUBSYS command after the Db2 connection to IMS has been established.

Procedure

To resolve IMS RREs:

To display the residual recovery entry (RRE) information, issue the following command:
```
/DISPLAY OASN SUBSYS subsystem-name
```
To purge the RRE, issue one of these commands:
- ```
/CHANGE SUBSYS subsystem-name RESET
```
- ```
/CHANGE SUBSYS subsystem-name RESET OASN nnnn
```
Where nnnn is the originating application sequence number that is listed in the display. The originating application sequence number is the schedule number of the program instance, indicating its place in the sequence of invocations of that program since the last cold start of IMS. IMS cannot have two indoubt units of recovery with the same schedule number.

Results

These commands reset the status of IMS; they do not result in any communication with Db2.