"ldapsearch" is used to pull down logonids from he ACF2 z/OS logonid database. The "sizelimit" option is one of the Global options in the slapd.conf file(Configuration File). "sizelimit" specifies the maximum number of objects returned to the requesting application from a search operation.
The "sizelimit" option on a ldapsearch is defined as follows (from the CA LDAP Server for z/OS Administrator Guide):
(optional) Specifies the maximum number of objects returned to the requesting application from a search operation. Use this option before any database section to make it the server default value. Configure this within a database section to make it database-specific. If both a server value and database value are supplied, the database value will override the server value. The valid range of values is 0 to 32767. The default is 500. For example:
A "sizelimit" of 0 imposes no limits. This will allow you to do a ldpasearch and pull down all of the logonids from the ACF2 LOGONID database.