Netscape NETSCAPE DIRECTORY SERVER 6.1 - ADMINISTRATOR, Administrator'S Manual

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About Indexes
354 Netscape Directory Server Administrator’s Guide • August 2002
Balancing the Benefits of Indexing
Before you create new indexes, balance the benefits of maintaining indexes against
the costs. Keep in mind that:
• Approximate indexes are not efficient for attributes commonly containing
numbers, such as telephone numbers.
• Substring indexes do not work for binary attributes. Equality indexes should
be avoided if the value is big (such as attributes intended to contain
photographs or passwords containing encrypted data).
• Maintaining indexes for attributes not commonly used in a search increase
overhead without improving global searching performance.
• Attributes that are not indexed can still be specified in search requests,
although the search performance may be degraded significantly, depending on
the type of search.
• Keep in mind that the more indexes you maintain, the more disk space you
will require.
The following example illustrates exactly how time consuming indexes can
become. Consider the procedure for creating a specific attribute:
1.
The Directory Server receives an add or modify operation.
2.
The Directory Server examines the indexing attributes to determine whether an
index is maintained for the attribute values.
3.
If the created attribute values are indexed, then the Directory Server generates
the new index entries.
4.
Once the server completes the indexing, the actual attribute values are created
according to the client request.
For example, suppose the Directory Server is asked to add the entry
dn: cn=John Doe, ou=People, o=example.com
objectclass: top
objectClass: person
objectClass: orgperson
objectClass: inetorgperson
cn: John Doe
cn: John
sn: Doe