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 may be used either instead of or in addition to the server's database cache. The database cache generally uses a more compact representation of the data, but the entry cache generally holds data in a format that can be more efficiently used by the server.
Unlike the database cache which is maintained by the underlying database, the entry cache is managed by the directory server itself. There are a number of different entry cache implementations that may be used.