Kbase P8856: What effect does Pin Shared Memory ( -pinshm startup option ) have on the database?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
30/12/2008 |
|
Status: Verified
GOAL:
What effect does Pin Shared Memory ( -pinshm startup option ) have on the database?
GOAL:
How to avoid swapping the shared memory to disk.
FACT(s) (Environment):
All Supported Operating Systems
Progress 9.x
OpenEdge 10.x
OpenEdge Category: Database
FIX:
According to the "Startup Command and Parameter Reference," issuing the -pinshm on database startup "prevents the database engine from swapping shared memory contents to disk."
Pinning the segments guarantees that the segments are always in memory. They are never swapped to disk. This prevents performance degradation of the database issuing the -pinshm.
The effect on the entire system, however, is that there will be less memory available for other things. If the system has multiple database using the -pinshm parameter, several of which are seldom used, the overall system may be negatively impacted.
Please note that at the time of writting, although there is nothing stopping -pinshm being used in the database startup parameters, -pinshm is not available on Windows or AIX platforms due to the OS differences in how shared memory is initialised.