Summary information |
|
|---|---|
Default value |
15 |
Range of values |
1–2147483647 |
Status |
Dynamic |
Display level |
Comprehensive |
Required role |
System Administrator |
permission cache entries determines the number of cache protectors per task. This parameter increases the amount of memory for each user connection and worker process.
Information about user permissions is held in the permission cache. When Adaptive Server checks permissions, it looks first in the permission cache; if it does not find what it needs, it looks in the sysprotects table. It is significantly faster if Adaptive Server finds the information it needs in the permission cache and does not have to read sysprotects.
However, Adaptive Server looks in the permission cache only when it is checking user permissions, not when permissions are being granted or revoked. When a permission is granted or revoked, the entire permission cache is flushed. This is because existing permissions have timestamps that become outdated when new permissions are granted or revoked.
If users on your Adaptive Server frequently perform operations that require their permissions to be checked, you may see a small performance gain by increasing the value of permission cache entries. This effect is not likely to be significant enough to warrant extensive tuning.
If users on your Adaptive Server frequently grant or revoke permissions, avoid setting permission cache entries to a large value. The space used for the permission cache would be wasted, since the cache is flushed with each grant and revoke command.
