Kbase P91519: Does the number of Shared Memory Segments used affects buffer hits?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
23/08/2004 |
|
Status: Unverified
GOAL:
Does the number of Shared Memory Segments used affects buffer hits?
FIX:
No, the number of shared memory segment allocated by the database has nothing to do with the value of the buffer hits.
The number shared memory segment is based on the total amount of shared memory allocated by startup parameters (-B, -Ma, -Mn, -n and -pinshm) and the size of shared memory determined by the OS kernel (SHMMAX).
Buffer hits is the percentage of reutilization of buffers from the shared memory.
So, by changing the number of shared memory segments itself will not affect buffer hits. In the other hand, by increasing the value of database buffers parameter (-B) to get a higher buffer hits can increase the number of shared memory segments allocated.