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Benefits: How Searches Use Indexes
126 Sun ONE Directory Server Installation and Tuning Guide • June 2003
An index file for a particular attribute such as CN may contain multiple types of
indexes. For instance, if CN is indexed in the
example databasefor equalityand for
substring matching, then
example_cn.db3 contains both equality and substring
indexes.
Refer to the Sun ONE Directory Server Administration Guide for:
• An overview of each index type
• Instructions oncreating and deleting indexes
• A list of default indexes created by Directory Server
• A list of system indexes required by Directory Server
Default indexes improve search performancein many situations, and include some
support for other applications such as messaging. In some cases, you may choose
to disable or even delete particular default indexes for performance reasons.
System indexes are those on which Directory Server depends. Do not delete or
modifythem.
Benefits: How Searches Use Indexes
Indexes speed up searches. An index contains a list of values,each associated with
a list of entry identifiers corresponding to the value. Directory Server can lookup
entries quickly using the lists of entry identifiers in indexes. Without an index to
manage a list of entries, Directory Server may have to check every entry in a suffix
to find matches for a search.
The reason an indexed search may require significantly less processing than an
unindexed search becomes evident when search request processing is explained.
Here is how Directory Server processes each search request:
1. A client application sends a search request to Directory Server.
International Which entries match for this international locale?
Presence Which entries have this attribute?
Substring Which entries have a value matching *foo* for this attribute?
Table 7-1 Standard Index Types (Continued)
Index Type Answers the question...