Kbase P46416: Are database FREE blocks backed up with PROBKUP?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
16/10/2008 |
|
Status: Verified
GOAL:
Are database FREE blocks backed up with PROBKUP?
GOAL:
Are empty database blocks backed up with PROBKUP?
GOAL:
Will the PROBKUP archive file reduce in size when many records are deleted?
GOAL:
Why doesn't the PROBKUP archive file reduce in size when many records are deleted?
GOAL:
How come after I delete data from the database, the backup is still large?
GOAL:
Does progress backup empty blocks?
GOAL:
What is my backup so large even after deleting lots of records?
GOAL:
Why is my backup so large?
FACT(s) (Environment):
UNIX
Windows
Progress 9.x
OpenEdge 10.x
FIX:
Once a data block becomes available for use (below a storage area's highwater mark) it is listed on the RM chain and remains on the RM chain for the life of the database. Empty data blocks (blocks containing no records) migrate to the RM chain. Even when an data block contain no records, it does not become a FREE block. Thus, it will get backed up as a data block and be contained within the PROBKUP archive file.
Index blocks do however become FREE blocks when they are emptied. FREE blocks are backed up and are always compressed. Thus, they can save space within a PROBKUP archive file.
The only way to backup fewer blocks is to lower the high water mark (which means truncating storage areas or rebuilding the database).
The size of the PROBKUP archive file can be reduced by using PROBKUP compression switch:
PROBKUP <dbname> <archive_file> -com
This will save significant space when backing up empty data blocks.