This policy setting allows you to specify the maximum limit of how many instances per page the database shim can return. ...

This policy setting allows you to specify the maximum limit of how many instances per page the database shim can return.  This policy setting enforces the allowed maximum for applications including those that do not respect the default.
 
If you enable this policy setting, you may specify the maximum limit of how many instances the database shim can return.

If you disable or do not configure this policy setting, there will be no limit of how many instances the database shim can return.