Overview Of The Searching Algorithm - Red Hat DIRECTORY SERVER 7.1 - ADMINISTRATOR Administrator's Manual

About Indexes
•
id2children.db4
examine an entry's immediate children.
•
dn.db4
entry and all the entries in the subtree beneath it.
•
dn2id.db4
distinguished name to its ID number.

Overview of the Searching Algorithm

Indexes are used to speed up searches. To understand how the directory uses
indexes, it helps to understand the searching algorithm. Each index contains a list
of attributes (such as the
corresponding to each value. Directory Server processes a search request as
follows:
An LDAP client application, such as the Directory Server Gateway, sends a
1.
search request to the directory.
The directory examines the incoming request to make sure that the specified
2.
base DN matches a suffix contained by one or more of its databases or
database links.
H
H
If the search request for each database attribute can be satisfied by a single
3.
index, then the server reads that index to generate a list of potential matches.
If there is no index for the attribute, the directory generates a candidate list
that includes all entries in the database, which makes the search considerably
slower.
If a search request contains multiple attributes, the directory consults multiple
indexes and then combines the resulting lists of candidate entries.
If there is an index for the attribute, the directory takes the candidate matches
4.
from the index files in the form of a series of entry ID numbers.
392 Red Hat Directory Server Administrator's Guide • May 2005
— Restricts the scope of one-level searches, searches that
— Controls the scope of subtree searches; searches that examine an
— Begins all searches efficiently by mapping an entry's
, common name, attribute) and a pointer to the entries
cn
If they do match, the directory processes the request.
If they do not match, the directory returns an error to the client indicating
that the suffix does not match. If a referral has been specified in the
attribute under
nsslapd-referral
the LDAP URL where the client can attempt to pursue the request.
, the directory also returns
cn=config