Directory Tree Design Examples - Red Hat DIRECTORY SERVER 8.1 - DEPLOYMENT Deployment Manual

If the base of a search is a view and the scope of the search is not a base, then the search is a views-
based search. Otherwise, it is a conventional search.
For example, performing a search with a base of dc=example, dc=com does not return any entries
from the virtual search space are returned; in fact, no virtual-search-space search is performed. Views
processing occurs only if the search base is ou=Location Views. This way, views ensure that the
search does not result in entries from both locations. (If it were a conventional DIT, entries from both
locations are returned.)
4.4.5. Effects of Virtual Views on Performance
The performance of views-based hierarchies depends on the construction of the hierarchy itself and
the number of entries in the DIT. In general, there may be a marginal change in performance (within a
few percentage points of equivalent searches on a conventional DIT) if virtual DIT views are enabled
in the directory service. If a search does not invoke a view, then there is no performance impact. Test
the virtual DIT views against expected search patterns and loads before deployment.
We also recommend that the attributes used in view filters be indexed if the views are to be used as
general-purpose navigation tools in the organization. Further, when a sub-filter used by views matches
a configured virtual list view index, that index is used in views evaluation.
There is no need to tune any other part of the directory specifically for views.
4.4.6. Compatibility with Existing Applications
Virtual DIT views are designed to mimic conventional DITs to a high degree. The existence of views
should be transparent to most applications; there should be no indication that they are working with
views. Except for a few specialized cases, there is no need for directory users to know that views are
being used in a Directory Server instance; views appear and behave like conventional DITs.
Certain types of applications may have problems working with a views-enabled directory service. For
example:
• Applications that use the DN of a target entry to navigate up the DIT.
This type of application would find that it is navigating up the hierarchy in which the entry physically
exists instead of the view hierarchy in which the entry was found. The reason for this is that views
make no attempt to disguise the true location of an entry by changing the DN of the entry to conform
to the view's hierarchy. This is by design - many applications would not function if the true location
of an entry were disguised, such as those applications that rely on the DN to identify a unique entry.
This upward navigation by deconstructing a DN is an unusual technique for a client application, but,
nonetheless, those clients that do this may not function as intended.
• Applications that use the numSubordinates operational attribute to determine how many entries
exist beneath a node.
For the nodes in a view, this is currently a count of only those entries that exist in the real search
space, ignoring the virtual search space. Consequently, applications may not evaluate the view with
a search.

4.5. Directory Tree Design Examples

The following sections provide examples of directory trees designed to support a flat hierarchy as well
as several examples of more complex hierarchies.
Effects of Virtual Views on Performance
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