Addition and removal of attributes from the attribute cache

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By using the attribute cache, you can resolve filters in memory rather than in the database. Usage of cache has the advantage of not being flushed like the filter cache each time an LDAP add, delete, modify, or modrdn operation is run. (Deprecated)

Note: Starting with the IBM® Security Verify Directory 10.0.1 release, attribute cache is deprecated. Henceforth, users must avoid the usage of attribute cache.

Draft comment: DanielNg

To decide which attributes you want to store in memory, you must consider:

The amount of memory available to the server
The size of the directory
The types of search filters the application typically uses

Note: The attribute cache manager can resolve both exact match filters and presence filters. It can also resolve complex filters that are conjunctive or disjunctive. Additionally, the subfilters within complex filters must be exact match, presence, conjunctive, or disjunctive.

Not all attributes can be added to the attribute cache. To determine whether an attribute can be added to the cache, use the ldapexop command:

For attributes that can be added

ldapexop -D <adminDN> -w <adminPW> -op getattributes -attrType attribute_cache 
-matches true

For attributes that cannot be added:

ldapexop -D <adminDN> -w <adminPW> -op getattributes -attrType attribute_cache 
-matches false

Draft comment: DanielNg

Attribute caching can be configured either manually or automatically. To manually configure attribute caching, an administrator first needs to know which attributes to cache. To make attribute cache most effective, the administrator must run cn=monitor searches. These searches provide information about the attributes that are cached, the amount of memory that is used by each attribute in the cache, the total amount of memory that is used by attribute caching, the amount of memory that is configured for attribute caching, and a list of the attributes that are most often used in search filters. Using this information, an administrator can determine the amount of memory that is allowed for attribute caching, and also, which attributes to cache whenever necessary.

Alternatively, when an administrator enables automatic attribute caching, the directory server tracks the combination of attributes that is useful to cache within the defined memory limits. The server then updates the attribute caching at a particular time and according to a time interval configured by the administrator.

Typically you want to put a limited number of attributes into the attribute cache because of memory constraints. To help determine which attributes you want to cache, view the Directory cache candidate list and Changelog cache candidate list for the 10 most frequently used attribute search filters by your applications. See Checking server status. Also, see Determining which attributes to cache in the Performance Tuning and Capacity Planning section of the IBM Security Verify Directory documentation for more information.