Time stamp recovery with PITR and UOR

Time stamp recovery with PITR (point-in-time recovery) and UOR (units of recovery) is described here.

The following diagram shows time stamp recovery with PITR (point-in-time recovery) and UOR (units of recovery).

Figure 1. Time stamp recovery with PITR (point-in-time recovery) and UOR (units of recovery)
The figure shows four vertical lines, representing units of recovery, that are staggered to indicate recovery at different points in time.

The vertical lines in this diagram represent the scope of a UOR. The top of each line is the beginning of a UOR. The bottom of each line is the end of the sync point for a UOR. For purposes of this figure, it is assumed that no other UORs have updated any of the database data set or areas on the recovery list. Updates from UORs shown are applied based on the recovery time:

  • If time stamp recovery with PITR is performed with recovery time A, no updates apply to any database data set or area on the recovery list.

    Recovery consists of image copies being restored to the database data sets and areas on the recovery list.

  • If time stamp recovery with PITR is performed with recovery time B, only updates from UOR2 apply to the database data sets and areas on the recovery list.

    It is the only UOR that has committed data.

  • If time stamp recovery with PITR is performed with recovery time C, updates apply to the database data sets and areas on the recovery list for UOR1 and UOR2 only.
  • If time stamp recovery with PITR is performed with recovery time D, updates apply to the database data sets and areas on the recovery list for UOR1, UOR2 and UOR4.