slapo-valsort (5) - Linux Manuals

slapo-valsort: Value Sorting overlay to slapd


slapo-valsort - Value Sorting overlay to slapd




The Value Sorting overlay can be used with a backend database to sort the values of specific multi-valued attributes within a subtree. The sorting occurs whenever the attributes are returned in a search response.

Sorting can be specified in ascending or descending order, using either numeric or alphanumeric sort methods. Additionally, a "weighted" sort can be specified, which uses a numeric weight prepended to the attribute values. The weighted sort is always performed in ascending order, but may be combined with the other methods for values that all have equal weights. The weight is specified by prepending an integer weight {<weight>} in front of each value of the attribute for which weighted sorting is desired. This weighting factor is stripped off and not returned in search results unless the valsort control is specified (

The valsort control requires a value consisting of a Sequence that contains a boolean flag. The weighting factor is only returned if the boolean value is TRUE. In lber-encode(3) format, the required value must conform to "{b}" syntax.


These slapd.conf options apply to the Value Sorting overlay. They should appear after the overlay directive.
valsort-attr <attribute> <baseDN> (<sort-method> | weighted [<sort-method>])
Configure a sorting method for the specified attribute in the subtree rooted at baseDN. The sort-method may be one of alpha-ascend, alpha-descend, numeric-ascend, or numeric-descend. If the special weighted method is specified, a secondary sort-method may also be specified. It is an error to specify an alphanumeric sort-method for an attribute with Integer or NumericString syntax, and it is an error to specify a numeric sort-method for an attribute with a syntax other than Integer or NumericString.


        database bdb
        suffix dc=example,dc=com
        overlay valsort
        valsort-attr member ou=groups,dc=example,dc=com alpha-ascend

To invoke ldapsearch(1) with the valsort control, the control value must be set appropriately. The following octets represent the desired "{b}" encoding:

        0x30 0x03 0x01 0x01 0xff

The control can be sent from the command-line using the base64 encoding of the value:

        ldapsearch -E


default slapd configuration file


This module was written in 2005 by Howard Chu of Symas Corporation. The work was sponsored by Stanford University.


slapd.conf(5), slapd-config(5).