Information on the parameters that can be used to enable and tune the use of CAPI cache by the Centrify DB2 plugin.
Question:
Centrify DB2 plugin can be configured to use the in-process memory CAPI cache which would greatly improve performance with Active Directory user and group lookups. But how do we enable the CAPI cache?
Answer:
To enable the CAPI cache, set the following parameter to 'true' in /etc/centrifydc/centrifydc.conf file. Default is disabled, 'false'
capi.cache.enabled: true
There are a few more parameters that can be configured to further tune the DB2 plugin CAPI cache. The listed values are the defaults.
This configuration parameter specifies the number of seconds that a positive cached object remains in the in-memory CAPI cache before it is refreshed. This parameter takes effect only if the inmemory CAPI cache is enabled.
capi.cache.ttl: 3600
This configuration parameter specifies the number of seconds that a negative cached object remains in the in-memory CAPI cache before it is refreshed. This parameter takes effect only if the in-memory CAPI SID cache is enabled.
capi.cache.negative.ttl: 3600
This configuration parameter specifies the maximum number of objects that are kept in the in-memory CAPI cache if the cache is enabled. If the number is exceeded, cached objects that are the oldest are replaced with new objects.
capi.cache.max.objects: 10000
This configuration parameter specifies the number of hash map buckets that are allocated if the in-memory CAPI cache is enabled.
capi.cache.hash.table.size: 769
Please note that after a change to any of the above parameters, DB2 instance needs to be restarted to take effect.