SunONE Entry Cache Test

The entry cache is a mechanism that uses system memory for holding entries in a manner that may be quickly accessed so that it is not necessary to decode them from the database whenever they are needed. Entry caching mechanisms are particularly effective when used with applications that access the same entry multiple times in a sequence of operations (for example, an application which first searches to find a user entry and then binds as that user to verify a password, which is a very common usage pattern).

The entry cache size and the maximum number of entries in the cache are configurable. If these values are not set prudently, then the entry cache may not be able to hold adequate entries to serve the search requests to the Directory server; this in turn will compel the Directory server to directly access the disk for fulfilling the requests. Direct disk accesses are resource-intensive operations, and should be avoided. To do so, you need to continuously monitor how the entry cache services requests, detect sizing irregularities quickly, and correct them. 

Using the SunONE Entry Cache test, you can track the requests to each database on the Directory server, observe how the cache handles these requests, and ascertain whether the cache size needs to be fine-tuned.

Target of the test : A Sun Java System Directory server

Agent deploying the test : An internal agent

Outputs of the test : One set of results per database configured for monitoring.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed


The host for which the test is to be configured.


Refers to the port at which specified host listens to.


Represents the server's Distinguished name. This value is to be specified when the server requires explicit authentication of requests. By default, this attribute is set to "none", implying that authentication is not required.


Specify the password to be used for authenticating the request. The password is to be specified whenever the DistinguishedName is not "none".

Confirm Password

Confirm the password (if specified) by retyping it here.


Specify a comma-separated list of databases to be monitored.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Cache hit ratio

Indicates the ratio of the number of entry cache tries for this database to successful entry cache lookups.


This number is based on the total lookups and hits since the last measurement period of the test. The closer this value is to 100% the better. Whenever a search operation attempts to find an entry that is not resident in the entry cache, the directory server has to perform a disk access to obtain the entry. Thus, as this ratio drops towards zero, the number of disk accesses increases and directory server search performance drops.

Entries present

Indicates the number of directory entries for this database currently resident in the entry cache.


The maximum number of entries that can be held by the cache can be configured using the nsslapd-cachesize parameter. If the value of this measure grows dangerously close to the nsslapd-cachesize setting, it indicates that the entry cache will soon lose its ability to hold new entries, after which, it may not be able to service search requests. You may want to consider tuning the nsslapd-cachesize setting under such circumstances, so as to avoid direct disk accesses.