Chapter 6. Managing indexes in Directory Server

• The presence index (pres) is a list of the entries that contain a particular attribute. For example, use this type when clients frequently perform searches, such as attribute=mail.
• The equality index (eq) improves searches for entries containing a specific attribute value. For example, an equality index on the cn attribute enables faster searches for cn=first_name last_name.
• The approximate index (approx) enables efficient approximate or sounds-like searches. For example, searches for cn~=first_name last_name, cn~=first_name, or cn~=first_nam (note the misspelling) would return an entry cn=first_name X last_name. Note that the metaphone phonetic algorithm in Directory Server supports only US-ASCII letters. Therefore, use approximate indexing only with English values.
• The substring index (sub) is a costly index to maintain, but it enables efficient searching against substrings within entries. Substring indexes are limited to a minimum of three characters for each entry. For example, searches for telephoneNumber=*555* return all entries in the directory with a value that contains 555 in the telephoneNumber attribute.
• International index speeds up searches for information in international directories. The process for creating an international index is similar to the process for creating regular indexes, except that it applies a matching rule by associating an object identifier (OID) with the attributes to be indexed.

• Approximate indexes are not efficient for attributes commonly containing numbers, such as phone numbers.
• Substring indexes do not work for binary attributes.
• Avoid equality indexes on attributes that contain big values, such as an image.
• Maintaining indexes for attributes that are not commonly used in searches increases the overhead without improving the search performance.
• Attributes that are not indexed can still be used in search requests, although the search performance can be degraded significantly, depending on the type of search.

Procedure

• For example, to add the roomNumber attribute to the default index with the index types eq and sub, enter:

  # ldapadd -D "cn=Directory Manager" -W -H ldap://server.example.com -x
  
  dn: cn=roomNumber,cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config
  objectClass: nsIndex
  objectClass: top
  cn: roomNumber
  nsSystemIndex: false
  nsIndexType: eq
  nsIndexType: sub

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  Explanation of the LDIF statement:

  • objectClass: nsIndex: Defines that this entry is an index entry.
  • objectClass: top: This object class is additionally required in index entries.
  • cn: Sets the name of the attribute to index.
  • nsSystemIndex: Indicates whether or not the index is essential to Directory Server operations.
  • nsIndexType: This multi-value attribute specifies the index types.

• For example, to add the pres index type to the default index attributes of the roomNumber attribute, enter:

  # ldapmodify -D "cn=Directory Manager" -W -H ldap://server.example.com -x
  
  dn: cn=roomNumber,cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config
  changetype: modify
  add: nsIndexType
  nsIndexType: pres

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• For example, to remove the pres index type from the default index attributes of the roomNumber attribute, enter:

  # ldapmodify -D "cn=Directory Manager" -W -H ldap://server.example.com -x
  
  dn: cn=roomNumber,cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config
  changetype: modify
  delete: nsIndexType
  nsIndexType: pres

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• For example, to remove the roomNumber attribute from the default index, enter:

  # ldapdelete -D "cn=Directory Manager" -W -H ldap://server.example.com -x cn=roomNumber,cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config

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Verification

• List the default index attributes to verify your changes:

  # ldapsearch -H ldap://server.example.com:389 -D "cn=Directory Manager" -W -b "cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config" -x -s one -o ldif-wrap=no

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Procedure

• For example, to add the roomNumber attribute to the index of the userRoot database with the index types eq and sub, enter:

  # dsconf <instance_name> backend index add --attr roomNumber --index-type eq --index-type sub --reindex userRoot

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  The --reindex option causes that Directory Server automatically re-indexes the database.

• For example, to add the pres index type to the index settings of the roomNumber attribute in the userRoot database, enter:

  # dsconf <instance_name> backend index set --attr roomNumber --add-type pres userRoot

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• For example, to remove the pres index type from the index settings of the roomNumber attribute in the userRoot database, enter:

  # dsconf <instance_name> backend index set --attr roomNumber --del-type pres userRoot

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• For example, to remove the roomNumber attribute from the index in the userRoot database, enter:

  # dsconf <instance_name> backend index delete --attr roomNumber userRoot

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Verification

• List the index settings of the userRoot database:

  # dsconf <instance_name> backend index list userRoot

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Prerequisites

• You created an indexing entry or added additional index types to the existing userRoot database.

Verification

• List the index settings of the userRoot database:

  # dsconf <instance_name> backend index list userRoot

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Prerequisites

• You are logged in to the instance in the web console.

Procedure

• Navigate to Database Suffixes suffix_name Indexes Database Indexes.

  • To add an attribute to the index:

    • Click Add Index.
    • Enter the attribute name to the Select An Attribute field.
    • Select the index types.
    • Select Index attribute after creation.
    • Click Create Index.

  • To update the index settings of an attribute:

    • Click the overflow menu next to the attribute, and select Edit Index.
    • Update the index settings to your needs.
    • Select Index attribute after creation.
    • Click Save Index.

  • To delete an attribute from the index:

    • Click the overflow menu next to the attribute, and select Delete Index.
    • Select Yes, I am sure, and click Delete.
    • In the Suffix Tasks menu, select Reindex Suffix.

Verification

• Navigate to Database Suffixes suffix_name Indexes Database Indexes, and verify that the index settings reflect the changes you made.

Verification

• Select the attribute for which you want to change the search key length, for example, cn.

• Dump the cn index:

  # dbscan -f /var/lib/dirsrv/slapd-<instance_name>/db/database/cn.db > /tmp/default_len

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• Configure the new search key length as described in section Changing the search key length in a substring index using the command line.

• Stop the instance to synchronize the database on the disk:

  # dsctl <instance_name> stop

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• Dump the cn index:

  # dbscan -f /var/lib/dirsrv/slapd-<instance_name>/db/database/cn.db > /tmp/len_2

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• Compare len_2 and default_len files:

  # diff /tmp/len_2 /tmp/default_len

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• before sets the number of entries returned before the targeted one.
• after sets the number of entries returned after the targeted one.
• index, count, and value help to determine the target entry. If you set value, the target entry is the first one having its first sorting attribute starting with the value. Otherwise, you set count to 0, and the target entry is determined by the index value (starting from 1). If the count value is higher than 0, the target entry is determined by the ratio index * number of entries / count.

Procedure

• Update the ACI in oid=2.16.840.1.113730.3.4.9,cn=features,cn=config:

  # ldapmodify -D "cn=Directory Manager" -W -H ldap://server.example.com -x
  
  dn: oid=2.16.840.1.113730.3.4.9,cn=features,cn=config*
  changetype: modify
  replace: aci
  aci: (targetattr != "aci")(version 3.0; acl "VLV Request Control"; allow( read, search, compare, proxy ) userdn = "ldap:///anyone";)

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Verification

• Perform a query with VLV control not specify a bind user:

  # ldapsearch -H ldap://server.example.com -b "ou=People,dc=example,dc=com" -s one -x -E 'sss=cn' -E 'vlv=1/2/70/0' uid

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  This command requires that the server allows anonymous binds.

  If the command succeeds but returns no entries, run the query again with a bind user to ensure that the query works when using authentication.

Prerequisites

• Your client applications use the VLV control.
• Client applications require to query a contiguous subset of a large search result.
• The directory contains a large number of entries.

Prerequisites

• You are logged in to the instance in the web console.
• Your client applications use the VLV control.
• Client applications require to query a contiguous subset of a large search result.
• The directory contains a large number of entries.