Persistent search allows you to track changes to a set of entries on an LDAP server that match a specified search criteria. After the initial search is performed, the server keeps track of the search criteria and sends back information when any entry that matches the criteria is added, modified, deleted, or renamed.
Persistent search alters the standard LDAP search operation so that it does not end after the initial set of entries matching the search criteria is returned. Instead, LD8klju8AP servers keep the search operation going until it is abandoned by the client or until the client unbinds. This provides clients and servers participating in persistent search with an active channel through which entries that change (and additional information about the changes that occur) can be communicated.
NOTE: A persistent search operation may not retrieve the updated information, if entries in the eDirectory database are updated frequently.
This section provides the following information:
Persistent search provides the following benefits:
An LDAP client application with high performance needs might want to maintain a temporary, local cache of information obtained through LDAP search, compare, or bind operations. To improve performance, the local cache is always consulted before sending a request to an LDAP server. A persistent search request where the changesOnly flag is FALSE can be used if it is desirable to prime the cache; otherwise changesOnly would typically be set to TRUE in the request.
Caches are used for reasons other than performance improvement as well. In some cases, they arise naturally out of a particular application's design. For example, an LDAP client designed for administration of information held in LDAP servers will undoubtedly generate screen displays that show information gleaned from an LDAP server. The screen display is a cache that is active and visible until the user of the application takes some action that causes different information to be displayed. A refresh button or similar control may be provided to the user to allow them to update the cached display. A persistent search request can be used instead by the administrative application to automatically refresh the screen display as soon as the underlying LDAP information changes.
Some LDAP clients, such as those that execute on a portable computer, may maintain a partial or complete offline copy of the entries stored in an LDAP server. While connected to the network, such a client can direct all queries to the copy of data it holds and use a persistent search to actively maintain the contents of the offline copy (alternatively, the client could direct requests to the LDAP server that is the source of the data).
An LDAP client application may want to take some action when an entry in the directory is changed. A persistent search request can be used to proactively monitor one or more LDAP servers for interesting changes that in turn cause specific actions to be taken by an application. For example, an electronic mail repository may want to perform a "create mailbox" task when a new person entry is added to an LDAP directory and a "delete mailbox" task when a person entry is deleted from an LDAP directory.
In ConsoleOne, right-click the LDAP-Server object.
Click the Persistent Search tab.
To enable or disable persistent search, click Enable Persistent Search.
Specify the maximum number of persistent search operations that can be running at the same time.
Enter 0 to activate unlimited search operations.
Specify whether size and time limits should be ignored after the persistent search request has sent the initial search result set.
If this option is not selected, the entire persistent search operation is subject to the search restrictions. If either limit is reached, the search will fail with the appropriate error message.
Click OK.