!!! Overview
[{$pagename}] is a [Microsoft Active Directory] value within the [LDAP policy in Active Directory] that controls how large this temporary database table can be. 


While a query is processed, the dblayer may try to create a temporary database table to sort and select intermediate results from. If the temporary database table would contain more objects than the value for [{$pagename}], the dblayer performs a much less efficient parsing of the complete DS database and of all the objects in the DS database.

Default value: 10,000 records

%%information
[{$pagename}] in [Windows Server 2008] and [Windows Server 2008 R2] has a Hardcoded limit which override [LDAP policy in Active Directory] setting when the policy value should be higher.
%%


[{$pagename}] seems to cause an issue when it is smaller than the total number of Objects, the [Virtual List View Control] may fail with a [LDAP Result Codes] of [Unavailable Critical Extension|LDAP_UNAVAILABLE_CRITICAL_EXTENSION] similar to:

{{{
LdapException: (12) Unavailable Critical Extension
LdapException: Server Message: 000020EF: SvcErr: DSID-03140552, problem 5010 (UNAVAIL_EXTENSION), data 0

Error code: 53
}}}

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
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* [#1] - [Virtual List View Active Directory search LdapException: Unavailable Critical Extension
|https://stackoverflow.com/a/60714199/88122|target='_blank'] - based on information obtained 2020-03-17