Data protection information in the form of before and after images of all updated records is written to the protection log during each Adabas session. This information is needed to remove or reapply updates.
The protection log may be assigned to a sequential dataset or to a dual/multiple protection log dataset (direct access) on disk. If the dual/multiple protection log is used, the ADARES PLCOPY function must be used to copy it to a sequential dataset. This dataset can be used as input to ADARES BACKOUT or REGENERATE.
Software AG does not recommend the use of 3480/3490 tape cartridge compression (IDRC) for protection log files. The ADARES utility BACKOUT function runs at least twice as long under OS/390 or z/OS when processing compressed data. Also, the BACKOUT function is not supported for compressed data on VSE/ESA and VM/ESA systems.
The ADARES BACKOUT {DPLOG | MPLOG} function is not valid for a cluster database. This is disallowed because a merged PLOG is required in order to perform the BACKOUT.
| BACKOUT | Back Out Updates Using the Sequential Protection Log (SIBA) |
| BACKOUT DPLOG or MPLOG | Back Out Updates Using the Dual or Multiple Protection Log |
