Paged search considerations

Paged searches allow an LDAP client to control the rate at which search entries are returned by requesting a page of entries at a time (the number of entries in a page is controlled by the client request). The LDAP client proceeds through the search result set by issuing successive requests for the next page of entries.

The LDAP server manages paged search requests in storage, caching the returned entries for the result set until they are retrieved by the client. Pervasive use of this capability by client applications increases the storage requirements of the LDAP server to hold these result sets. In particular, very large result sets use large amounts of storage for a paged search. If paged searches are enabled in the LDAP server, consider increasing the storage allowed in the LDAP server. If necessary, consider running the LDAP server in 64-bit addressing mode.

The following configuration options contribute in controlling the resources that might be used for paged search requests:

ibm-slapdPagedResAllowNonAdmin: This is a configuration attribute in the cn=configuration entry in the CDBM backend. Setting this attribute value to "false" restricts paged search requests to administrators. This avoids widespread use of the facility and its associated resources on behalf of general users.
ibm-slapdPagedResLmt: This is a configuration attribute in the cn=configuration entry in the CDBM backend. This limits the number of concurrent paged search requests on a given connection. For cases where LDAP client applications issue multiple active requests per connection, limiting this to a small number can help limit the overall number of paged search result sets that are cached in the LDAP server. Setting this to "0" disables paged searches.
sizeLimit: This is a configuration option in the LDAP server configuration file that limits the number of entries returned on a given search request. This is also managed with group search limits. See Managing group search limits for more information about group search limits. Search size limits inherently limit the size of the paged search result sets cached by the LDAP server.

See cn=configuration for more information about the ibm-slapdPagedResLmt and ibm-slapdPagedResAllowNonAdmin attributes in the cn=configuration entry. Also, see pagedResults for more information about the pagedResults server control.