Kbase P79159: What is the sequence of events when ai extents are switched and then backed up?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
16/10/2008 |
|
Status: Unverified
GOAL:
What is the sequence to backup ai extents and re-use space.
FIX:
After-image files should not be stopped prior to backing up an extent. If after-image is stopped before the extents are backed up, that data in the ai extents can not be accessed.
When you enter
command: rfutil <dbname> -C aimage end
the ai extents are immediately marked as empty.
Below is the series of steps that will backup ai extents and re-use space:
With ai running:
1. Use multiple extents ( at least 3 are recommended ) so that when an ai extent becomes full, the database engine can automatically switch over to the next ai extent.
2. After an ai extent switch, backup the full extent. This can only be done using a system utility.
3. Mark the full extent as empty:
command: rfutil <dbname> -C aimage extent empty [extent-path].
Later Progress will be able to re-use this extent when the other extent(s)
become full.
4. Monitor the ai extent size, and periodically truncate the ai. This is not done automatically when the extent is marked as empty. When an ai extent is marked as empty, the space is re-used, that is, previous data is overwritten, but not truncated. So, in order to free up the space from the variable extents, they need to be truncated after they have been backed up and marked as empty.
command: rfutil <dbname> -C aimage truncate. When you execute this command, after-imaging and two-phase commit