"ldapsearch" is used to pull down acids from the TOP SECRET Security file. 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 TOP SECRET z/OS LOGONID database.
Details can be found in "Chapter 10: z/OS UNIX System Services Command Line Utilities" of the CA LDAP Server for z/OS Administrator Guide.