Kbase P135179: What is RecSpaceSearchDepth?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
14/04/2010 |
|
Status: Verified
GOAL:
What is RecSpaceSearchDepth?
GOAL:
What does -recspacesearchdepth do?
GOAL:
What is the Record free chain search depth factor?
FACT(s) (Environment):
All Supported Operating Systems
OpenEdge 10.1B
OpenEdge 10.2x
FIX:
The database startup parameter "-recspacesearchdepth" was first introduced in OpenEdge 10.1B02. The setting determines how deep in the record free chain to search, to find a block with enough free space to fit the data, before allocating a new clusters worth of space instead.
The default value is 5 and the maximum value is 100.
WARNING:
This parameter should not be changed unless Progress Technical Support and Progress Development advise that after analysis, changing the value may correct observed behaviour under investigation.
Some historical background:
The default space allocation algorithms were not optimised for specific data growth scenario's. So, recspacesearchdepth was added to fix an issue with the record space allocation algorithm where Type II storage areas were not searching deep enough into the RM chain for available space before allocating a new cluster. The current default value (5) is a factor used in the new record space algorithm along with the cluster size of the current area.
The default value of this parameter has since proven to make the algorithm sufficiently search the record free chain for available space. If proutil -C chanalys shows more than one clusters worth of free space on the RM chain over a prolonged period of time, then changing this value may be warranted but contact Progress Technical Support before doing it.
Either free space won't be used properly if set too low or if the search is too deep performance will drop.