Service manual

Costs: How Updates Affect Indexes
130 Sun ONE Directory Server Installation and Tuning Guide • June 2003
The cost of equalityindexes is generally lower than for substring indexes, for
example, but higher in terms of space than for presence. Some client applications
such as messaging servers may, however, rely on equality indexes for top search
performance.Avoid equalityindexes for largebinary attributessuch as photos and
encryptedpasswords.
Substring Indexes
Figure 7-3 depicts a substring index for the SN (surname) attribute. It shows an
excerpt of how this index maintains a series of lists per attribute value.
Directory Server indexes substrings such that searches for two-character substrings
maybefoundintheindex.Asearchfor
(sn=*ab*) can therefore be accelerated
using an index, for example, but a search for
(sn=*a*) cannot.
Figure 7-3 Representation of a Substring Index
Entry IDs
entryid
# entry-id: 23
dn: uid=yyorgens,ou=People,dc=example,dc=com
objectclass: top
objectclass: person
objectclass: organizationalPerson
objectclass: inetOrgPerson
uid: yyorgens
givenName: Yolanda
sn: Yorgenson
cn: Yolanda Yorgenson
mail: [e-mail]
secretary: uid=bcubbins,ou=People,dc=example,dc=com
...
on$
*son
^yo
*yor
*org
*rge
*gen
SN
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