Kbase P49128: When should the -Bp parameter be used with a Progress Online Probkup?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
5/11/2010 |
|
Status: Verified
GOAL:
When should the -Bp client parameter be used with a Progress Online Probkup?
GOAL:
Should Private Read-only buffers be used with online backup?
GOAL:
Why should the -Bp client parameter be used with a Progress Online Probkup?
GOAL:
What should the -Bp be set to when doing a Progress hot backup?
FACT(s) (Environment):
All Supported Operating Systems
Progress 9.1E
OpenEdge 10.0B
FIX:
A change was made to the probkup online routine in Progress 9.1E01 and OpenEdge 10.0B02 to improve performance. Where, although blocks already in the buffer pool at the time of online probkup are never moved to the Least Recently Used (LRU) end, if a buffer (to be backed up) already exists in the buffer pool at the LRU end, it is no longer moved from it's current position in the (LRU) chain to the MRU (Most Recently Used) end.
In addition, an enhancement was also made to probkup online which allows an online backup to make use of (-Bp) Private Read-Only Buffers. This enhancement is in addition to the performance improvement mentioned above. In effect, rather than always holding all the buffers needed at the LRU end of the chain of buffers in the buffer pool, by using is -Bp the probkup online routine will use its own private buffer list when needed.
Without using -Bp, users connections needing a new buffer will have to "jump" over those buffers held by the backup process. Once the online probkup routine has completed, buffers will be evicted from the LRU chain or promoted to the MRU (Most Recently Used) chain as appropriate.
It is therefore highly recommended to use (-Bp) Private Buffers with an online probkup and the suggested value is 10.
$ probkup online <dbname> <backup_pathANDbackup_name> -Bp 10
Incrementing the -Bp would be a tuning exercise and results are likely to vary greatly due to the dynamic nature of production online databases and very unlikely to be needed much higher provided that -B is appropriately scoped for the application environment. Before considering increasing -Bp, please refer to Progress Solution P95829 to understand Read only Private Buffers.